OffShore Aquaculture

Offshore aquaculture, also known as open ocean aquaculture, is an emerging approach to mariculture or marine farming where fish farms are moved some distance offshore. The farms are positioned in deeper and less sheltered waters, where ocean currents are stronger than they are inshore.[1][2] See below link on Salmon farming controversy.

One of the concerns with inshore aquaculture is that discarded nutrients and feces can settle below the farm on the seafloor and damage the benthic ecosystem.[3]

According to its proponents, the wastes from aquaculture that has been moved offshore tend to be swept away from the site and diluted. Moving aquaculture offshore also provides more space where aquaculture production can expand to meet the increasing demands for fish. It avoids many of the conflicts that occur with other marine resource users in the more crowded inshore waters, though there can still be user conflicts offshore. Critics are concerned about issues such as the ongoing consequences of using antibiotics and other drugs and the possibilities of cultured fish escaping and spreading disease among wild fish.[2][4]

Background

Aquaculture is the most rapidly expanding food industry in the world[5] as a result of declining wild fisheries stocks and profitable business.[1] In 2008, aquaculture provided 45.7% of the fish produced globally for human consumption; increasing at an mean rate of 6.6% a year since 1970.[6]

In 1970, a National Oceanic and Atmospheric Administration (NOAA) grant brought together a group of oceanographers, engineers and marine biologists to explore whether offshore aquaculture, which was then considered a futuristic activity, was feasible.[7] In the United States, the future of offshore aquaculture technology within federal waters has become much talked-about.[8] As many commercial operations show, it is now technically possible to culture finfish, shellfish, and seaweeds using offshore aquaculture technology.[8]

Major challenges for the offshore aquaculture industry involve designing and deploying cages that can withstand storms, dealing with the logistics of working many kilometers from land, and finding species that are sufficiently profitable to cover the costs of rearing fish in exposed offshore areas.[9]

Technology

To withstand the high energy offshore environment, farms must be built to be more robust than those inshore.[1][10] However, the design of the offshore technology is developing rapidly, aimed at reducing cost and maintenance.[11]

While the ranching systems currently used for tuna use open net cages at the surface of the sea (as is done also in salmon farming), the offshore technology usually uses submersible cages.[1] These large rigid cages – each one able to hold many thousands of fish – are anchored on the sea floor, but can move up and down the water column.[11] They are attached to buoys on the surface which frequently contain a mechanism for feeding and storage for equipment.[11] Similar technology is being used in waters near the Bahamas, China, the Philippines, Portugal, Puerto Rico, and Spain.[11] By submerging cages or shellfish culture systems, wave effects are minimized and interference with boating and shipping is reduced.[1][12] Offshore farms can be made more efficient and safer if remote control is used,[13] and technologies such as an 18-tonne buoy that feeds and monitors fish automatically over long periods are being developed.[11]

Existing offshore structures

Multi-functional use of offshore waters can lead to more sustainable aquaculture "in areas that can be simultaneously used for other activities such as energy production".[12] Operations for finfish and shellfish are being developed. For example the Hubb-Sea World Research Institutes’ project to convert a retired oil platform 10 nm off the southern California coast to an experimental offshore aquaculture facility.[14] The institute plans to grow mussels and red abalone on the actual platform, as well as white seabass, striped bass, bluefin tuna, California halibut and California yellowtail in floating cages.[14]

Integrated multi-trophic aquaculture

Integrated multi-trophic aquaculture (IMTA), or polyculture, occurs when species which must be fed, such as finfish, are cultured alongside species which can feed on dissolved nutrients, such as seaweeds, or organic wastes, such as suspension feeders and deposit feeders.[15] This sustainable method could solve several problems with offshore aquaculture.[15] The method is being pioneered in Spain, Canada, and elsewhere.[8]

Roaming cages

Roaming cages have been envisioned as the "next generation technology" for offshore aquaculture.[11] These are large mobile cages powered by thrusters and able to take advantage of ocean currents.[11] One idea is that juvenile tuna, starting out in mobile cages in Mexico, could reach Japan after a few months, matured and ready for the market.[1] However, implementing such ideas will have regulatory and legal implications.[11]

Space conflicts

As oceans industrialize, conflicts are increasing among the users of marine space.[16] This competition for marine space is developing in a context where natural resources can be seen as publicly owned.[17] There can be conflict with the tourism industry,[18] recreational fishers,[17] wild harvest fisheries[19] and the sitting of marine renewable energy installations.[20] The problems can be aggravated by the remoteness of many marine areas, and difficulties with monitoring and enforcement.[20] On the other hand, remote sites can be chosen that avoid conflicts with other users, and allow large scale operations with resulting economies of scale.[2] Offshore systems can provide alternatives for countries with few suitable inshore sites, like Spain.[2]

Ecological impacts

Inshore marine farming systems in shallow sheltered water, as depicted here, can have problems with waste collecting on the sea floor. These problems are lessened with offshore aquaculture, where wastes are swept away from the site and diluted.

See also: Fish diseases and parasites

Compared to inshore aquaculture, disease problems currently appear to be much reduced when farming offshore. For example, parasitic infections that occur in mussels cultured offshore are much smaller than those cultured inshore.[12] However, new species are now being farmed offshore although little is known about their ecology and epidemiology.[1] The implications of transmitting pathogens between such farmed species and wild species "remains a large and unanswered question".[24]

Spreading of pathogens between fish stocks is a major issue in disease control.[24] Static offshore cages may help minimize direct spreading, as there may be greater distances between aquaculture production areas. However, development of roaming cage technology could bring about new issues with disease transfer and spread. The high level of carnivorous aquaculture production results in an increased demand for live aquatic animals for production and breeding purposes such as bait, broodstock and milt. This can result in spread of disease across species barriers.[24]

Employment

Aquaculture is encouraged by many governments as a way to generate jobs and income, particularly when wild fisheries have been run down.[1] However, this may not apply to offshore aquaculture. Offshore aquaculture entails high equipment and supply costs, and therefore will be under severe pressure to lower labor costs through automated production technologies.[5] Employment is likely to expand more at processing facilities than grow-out industries as offshore aquaculture develops.[1]

Prospects

Norway and the United States are currently (2008) making the main investments in the design of offshore cages.[25]

FAO

In 2010, the Food and Agriculture Organization (FAO) sub-committee on aquaculture made the following assessments:

"Most Members thought it inevitable that aquaculture will move further offshore if the world is to meet its growing demand for seafood and urged the development of appropriate technologies for its expansion and assistance to developing countries in accessing them [...] Some Members noted that aquaculture may also develop offshore in large inland water bodies and discussion should extend to inland waters as well [...] Some Members suggested caution regarding potential negative impacts when developing offshore aquaculture.[26]

The sub-committee recommended the FAO "should work towards clarifying the technical and legal terminology related to offshore aquaculture in order to avoid confusion."[26]

Europe

In 2002, the European Commission issued the following policy statement on aquaculture:[27]

"Fish cages should be moved further from the coast, and more research and development of offshore cage technology must be promoted to this end. Experience from outside the aquaculture sector, e.g. with oil platforms, may well feed into the aquaculture equipment sector, allowing for savings in the development costs of technologies."

By 2008, European offshore systems were operating in Norway, Ireland, Italy, Spain, Greece, Cyprus, Malta, Croatia, Portugal and Libya.[2]

In Ireland, as part of their National Development Plan, it is envisioned that over the period 2007–2013, technology associated with offshore aquaculture systems will be developed, including: "sensor systems for feeding, biomass and health monitoring, feed control, telemetry and communications [and] cage design, materials, structural testing and modelling."[28]

United States

"One of the reasons that aquaculture is going to be so important for us in the future is that we have calculated that by 2025, we're going to need 4 million metric tons more seafood than we are currently consuming today, in this country. There is no way that that production is going to come from wild stock fisheries, so we're going to have to go to aquaculture. (the other thing is that) by moving the aquaculture industry offshore, we can move into cleaner, deeper waters, we can reduce conflicts with coastal users and we can provide a much better environment for aquaculture operations to exist. The aquaculture industry is going to keep growing globally and it only makes sense to have some of the economic benefits for that expansion accrue to the United States.(Linda Chaves. Aquaculture Coordinator for the National Oceanic and Atmospheric Administration (NOAA))

Moving aquaculture offshore into the exclusive economic zone (EEZ) can cause complications with regulations. In the United States, regulatory control of the coastal states generally extends to 3 nm, while federal waters (or EEZ) extend to 200 nm offshore.[8] Therefore, offshore aquaculture can be sited outside the reach of state law but within federal jurisdiction.[1] As of 2010, "all commercial aquaculture facilities have been sited in nearshore waters under state or territorial jurisdiction."[4] However, "unclear regulatory processes" and "technical uncertainties related to working in offshore areas" have hindered progress.[4] The five offshore research projects and commercial operations in the US – in New Hampshire, Puerto Rico, Hawaii and California – are all in federal waters.[8] In June 2011, the National Sustainable Offshore Aquaculture Act of 2011 was introduced to the House of Representatives "to establish a regulatory system and research program for sustainable offshore aquaculture in the United States exclusive economic zone".[29][30]

Offshore aquaculture uses fish cages similar to these inshore ones, except they are submerged and moved offshore into deeper water.

Current species

By 2005, offshore aquaculture was present in 25 countries, both as experimental and commercial farms.[5] Market demand means that the most offshore farming efforts are directed towards raising finfish.[8] Two commercial operations in the US, and a third in the Bahamas are using submersible cages to raise high-value carnivorous finfish, such as moi, cobia, and mutton snapper.[1] Submersible cages are also being used in experimental systems for halibut, haddock, cod, and summer flounder in New Hampshire waters, and for amberjack, red drum, snapper, pompano, and cobia in the Gulf of Mexico.[1]

The offshore aquaculture of shellfish grown in suspended culture systems, like scallops and mussels, is gaining ground. Suspended culture systems include methods where the shellfish are grown on a tethered rope or suspended from a floating raft in net containers.[12] Mussels in particular can survive the high physical stress levels which occur in the volatile environments that occur in offshore waters. Finfish species must be feed regularly, but shellfish do not, which can reduce costs.[12] The University of New Hampshire in the US has conducted research on the farming of blue mussels submerged in an open ocean environment.[31] They have found that when farmed in less polluted waters offshore,[32] the mussels develop more flesh with lighter shells.[31]

Global status: E = Experimental, C = Commercial

Global status of offshore aquaculture

Aquaculture Collaborative Research Support Program [33]

Location Species Status Comment

Australia tuna C 10,000 tones/year worth A$250 million

California striped bass, California yellowtail, Pacific halibut, abalone E/C Attempts to produce from an oil platform

Canada cod, sablefish, mussels, salmon Mussels established in eastern Canada

Canary Islands seabass, seabream Two cages installed but not now used

China unknown finfish, scallops E Small scale experiments on finfish

Croatia tuna C 8 offshore cages (1998)

Cyprus seabass, seabream C 8 offshore cages (1998)

Faeroe Island Failed trials

France seabass, seabream C 13 offshore cages (1998)

Germany seaweed, mussels E Trials using wind-farms

Greece seabass, seabream C

Hawaii amberjack, Pacific threadfin C

Ireland Atlantic salmon E Various experimental projects

Italy seabass, seabream, tuna C

Japan tuna, mussels C Commercial tuna ranching, offshore mussel long-lines.

Korea scallop

Malta seabass, seabream, tuna C 3 offshore cages (1998)

Mexico tuna C

Morocco tuna C

New Hampshire Atlantic halibut, cod, haddock, mussels, sea scallops, summer flounder E/C Experimental work from the University of New Hampshire, two commercial mussel sites

New Zealand mussels About to become operational

Panama tuna C

Puerto Rico cobia, snapper C

Spain seabass, seabream C Government assisting trials

Turkey seabass, seabream C

Washington sablefish C

Taiwan cobia C 3,000 tonnes (2001)

La Acuicultura en mar abierto es un enfoque emergente para la maricultura o cultivo marino donde las granjas de peces se mueven a cierta distancia de la costa. Las fincas están situadas en aguas más profundas y menos protegidos , donde las corrientes oceánicas son más fuertes de lo que son cerca de la costa . [ 1 ] [ 2 ]

Una de las preocupaciones con la acuicultura de aguas someras es que los nutrientes y heces desechadas pueden instalarse debajo de la granja en el fondo marino y dañar el ecosistema bentónico . [ 3 ] Según sus defensores , los residuos procedentes de la acuicultura que se ha trasladado al exterior tienden a ser barrido del sitio y diluida . Mover la acuicultura en mar también proporciona más espacio en el que la producción de la acuicultura puede expandirse para satisfacer la creciente demanda de pescado. Se evita muchos de los conflictos que se producen con otros usuarios de los recursos marinos en las aguas costeras más concurridas , aunque todavía puede haber conflictos con los usuarios de la costa. Los críticos están preocupados por cuestiones tales como las consecuencias actuales de la utilización de antibióticos y otras drogas y las posibilidades de pescado cultivado que se escapa y la propagación de enfermedades entre los peces silvestres . [ 2 ] [ 4 ]

Antecedentes

La acuicultura es la industria alimentaria más rápida expansión en el mundo [ 5 ] como resultado de la disminución de las poblaciones de peces silvestres y de negocio rentable [ 1 ] En 2008 , la acuicultura proporciona el 45,7 % de los peces producidos en el mundo para el consumo humano . ; aumentando a una tasa media de 6,6 % al año desde 1970 . [ 6 ]

En 1970, un (NOAA ) de subvención Administración Nacional Oceánica y Atmosférica reunió a un grupo de oceanógrafos , ingenieros y biólogos marinos para explorar si la acuicultura en mar abierto , lo que entonces se consideraba una actividad futurista, era factible. [ 7 ] En los Estados Unidos, la futuro de la tecnología de la acuicultura en alta mar en aguas federales se ha convertido tanto se habla . [ 8 ] Como muchas operaciones comerciales muestran , ahora es técnicamente posible a los pescados en cultura , mariscos y algas marinas que utilizan la tecnología de la acuicultura marina. [ 8 ]

Los principales desafíos para la industria de la acuicultura en mar implican el diseño y la implementación de las jaulas que puedan resistir las tormentas , que trata de la logística de trabajo de muchos kilómetros de tierra , y la búsqueda de especies que son suficientemente rentables para cubrir los costos de la crianza de peces en zonas de altura expuestas. [ 9 ]

Tecnología

Para soportar el ambiente marina alta energía , las granjas deben ser construidos para ser más robustos que los de bajura . [ 1 ] [ 10 ] Sin embargo , el diseño de la tecnología en alta mar se está desarrollando rápidamente , destinada a reducir el costo y el mantenimiento. [ 11 ]

Mientras que los sistemas de explotación que actualmente se utilizan para el uso de atún jaulas abiertas en la superficie del mar (como se hace también en el cultivo de salmón ), la tecnología en alta mar por lo general utiliza jaulas sumergibles [ 1 ] Estos grandes jaulas rígidas - . Cada una capaz de contener muchos miles de peces - están anclados en el fondo del mar , pero pueden moverse hacia arriba y hacia abajo la columna de agua [ 11 ] Ellos están unidos a boyas en la superficie , que contienen con frecuencia un mecanismo de alimentación y almacenamiento para equipos [ 11 ] una tecnología similar es . . que se utiliza en aguas cercanas a las Bahamas , China , Filipinas, Portugal, Puerto Rico y España. [ 11 ] Al sumergir jaulas o sistemas de cultivo de mariscos , los efectos de la onda se reducen al mínimo y la interferencia con la navegación y el transporte marítimo se reduce. [ 1 ] [ 12 ] explotaciones offshore pueden hacerse más eficiente y más seguro si se utiliza el control remoto, [ 13] y se están desarrollando tecnologías como una boya de 18 toneladas que se alimenta y controla automáticamente los peces durante largos períodos. [ 11 ]

Las estructuras en alta mar

Uso de múltiples funciones de las aguas en alta mar puede conducir a la acuicultura más sostenible " en las áreas que se pueden utilizar al mismo tiempo para otras actividades, como la producción de energía " . Se están desarrollando [ 12 ] Las operaciones para el pescado y los mariscos. Por ejemplo, el proyecto de Hubb -Sea World Research Institutes ' para convertir una plataforma petrolera jubilado 10 nm frente a la costa sur de California a un centro experimental de acuicultura en alta mar. [ 14 ] El instituto planea crecer mejillones y abalones rojos en la plataforma actual , así como la lubina blanca, bajo rayado , atún rojo, lenguado de California y California amarilla en jaulas flotantes. [ 14 ]

Integrado a acuicultura multitrófica

Integrado acuicultura multi- trófica ( IMTA) , o policultivo , se produce cuando las especies que deben ser alimentados , como peces , se cultivan junto con las especies que pueden alimentarse de los nutrientes disueltos , tales como algas o residuos orgánicos , tales como alimentadores de suspensión y alimentadores de depósito . [ 15 ] Este método sostenible podría resolver varios problemas con la acuicultura en mar abierto . [ 15 ] El método está siendo pionera en España , Canadá y otros lugares. [ 8 ]

Jaulas móviles (como barcaza)

Las Jaulas móviles se han concebido como la " tecnología de la próxima generación " para la acuicultura en mar abierto . [ 11 ] Estos son grandes jaulas móviles accionados por propulsores y capaz de tomar ventaja de las corrientes oceánicas . [ 11 ] Una idea es que el atún juvenil, empezando en jaulas móviles en México , podrían llegar a Japón después de un par de meses, y listos para el mercado. [ 1 ] Sin embargo , la implementación de estas ideas tendrán implicaciones regulatorias y legales. [ 11 ]

Conflictos espaciales

Dado que los océanos se industrializan , los conflictos están aumentando entre los usuarios del espacio marino. [ 16 ] Esta competencia por el espacio marino está desarrollando en un contexto donde los recursos naturales pueden ser vistos como propiedad pública . [ 17 ] No puede haber conflicto con la industria del turismo, [ 18 ] los pescadores deportivos , [ 17 ] la pesca de recolección silvestre [ 19] y la sesión de instalaciones marítimas de energía renovable. [ 20 ] los problemas pueden ser agravados por la lejanía de muchas áreas marinas , y las dificultades con la vigilancia y el cumplimiento . [ 20 ] en por otra parte, los sitios remotos se puede elegir que evitar conflictos con otros usuarios , y permitir que las operaciones a gran escala con las economías de escala resultantes . [ 2] Los sistemas offshore pueden ofrecer alternativas para países con pocos sitios costeros adecuados, como España . [ 2 ]

Impactos ecológicos

Sistemas de cultivos marinos de bajura en el agua poco profunda protegida , tal como se muestra aquí , pueden tener problemas con la recogida de residuos en el suelo marino . Estos problemas se reducen a la acuicultura en alta mar, donde los desechos son arrastrados fuera del lugar y se diluyen .

Ver también: La acuicultura de salmón # Problemas

Los impactos ecológicos de la acuicultura en alta mar son un tanto incierto , ya que sigue siendo en gran medida en la etapa de investigación. [ 1 ] Muchas de las preocupaciones sobre los posibles impactos de la acuicultura en alta mar son paralelos a preocupaciones similares , bien establecidos sobre las prácticas de acuicultura de bajura. [ 21 ]

Polución

Una de las preocupaciones con las granjas costeras es que los nutrientes y heces desechados pueden asentarse en el fondo marino y perturbar el bentos . [ 3 ] La " dilución de nutrientes " que se produce en aguas profundas es una razón de peso para mover la acuicultura costera en alta mar en el océano abierto . [ 22 ] ¿Cuánto contaminación de nutrientes y daños en el fondo marino se produce depende de la eficiencia de conversión alimenticia de las especies , la tasa de descarga y el tamaño de la operación . [ 1 ] Sin embargo , disuelven y nutrientes de partículas todavía se liberan al medio ambiente . [ 14 ] las futuras explotaciones en alta mar será probablemente mucho mayor que las granjas costeras de hoy, y por lo tanto va a generar más residuos. [ 15 ] el punto en que se supere la capacidad de los ecosistemas marinos para asimilar los residuos procedentes de las operaciones de acuicultura en alta mar aún no se ha definido . [ 15 ]

Suministro de alimento por Captura de crías y peces silvestres

Al igual que con la acuicultura de agua somera de peces carnívoros , una gran proporción de la alimentación proviene de peces de forraje silvestres . A excepción de unos pocos países , la acuicultura marina se ha centrado principalmente en los peces carnívoros de alto valor . [ 5 ] Si los intentos de la industria para expandir con este enfoque , entonces el suministro de estos peces silvestres se volverán ecológicamente insostenible . [ 1 ]

Escapes de peces

El gasto de los sistemas costa afuera significa que es importante para evitar los escapes de peces . [ 1 ] Sin embargo, es probable que haya escapes como la industria offshore se expande. [ 1 ] Esto podría tener consecuencias importantes para las especies nativas , aunque los peces de cultivo son dentro de su área de distribución natural . [ 1 ] jaulas sumergibles están totalmente cerradas , por lo que se escapa sólo puede ocurrir a través de los daños a la estructura. Jaulas en alta mar deben soportar la alta energía del medio ambiente y los ataques de depredadores como los tiburones [ 11 ] La malla exterior está hecha de Spectra - . Un súper fuerte fibra de polietileno - envuelto firmemente alrededor del marco , sin dejar holgura para los depredadores para agarrar . [ 11 ] Sin embargo , los huevos fertilizados de bacalao son capaces de pasar a través de la malla de la jaula en recintos al mar. [ 23 ]

Enfermedades

En comparación con la acuicultura de aguas someras , aparecen en la actualidad problemas de enfermedades que ser mucho más reducido cuando la agricultura de la costa. Por ejemplo , las infecciones parasitarias que se presentan en los mejillones cultivados en alta mar son mucho más pequeños que los cultivados en aguas someras . [ 12 ] Sin embargo , las nuevas especies están siendo cultivadas en alta mar , aunque se sabe poco sobre su ecología y epidemiología. [ 1 ] Las implicaciones de la transmisión de patógenos entre tales especies cultivadas y las especies silvestres " sigue siendo una pregunta sin respuesta y gran " . [ 24 ]

Propagación de agentes patógenos entre los recursos pesqueros es un problema importante en el control de la enfermedad . [ 24 ] jaulas oceánicas estáticas pueden ayudar a disminuir la expansión directa, ya que puede haber una mayor distancia entre las zonas de producción acuícola . Sin embargo , el desarrollo de la tecnología de itinerancia jaula podría dar lugar a nuevos problemas con la transmisión de enfermedades y la propagación . El alto nivel de carnívoros resultados de la producción de la acuicultura en una mayor demanda de animales acuáticos vivos con fines de producción y de reproducción , como cebo, reproductores y esperma . Esto puede resultar en la propagación de la enfermedad a través de barreras de especies . [ 24 ]

Empleo

La acuicultura se siente alentado por muchos gobiernos como una manera de generar puestos de trabajo e ingresos , sobre todo cuando la pesca silvestre se han agotado. [ 1 ] Sin embargo, esto no puede aplicarse a la acuicultura oceánica . La acuicultura offshore implica alta Equipo y materiales para los costos, y por lo tanto estará bajo una fuerte presión para reducir los costos de mano de obra a través de las tecnologías de producción automatizadas . [ 5 ] es probable que se expanda más en las instalaciones de procesamiento que las industrias de crecimiento posterior como se desarrolla la acuicultura oceánica Empleo. [ 1 ]

Perspectivas

Noruega y los Estados Unidos son en la actualidad ( 2008 ) toma las principales inversiones en el diseño de las jaulas en alta mar. [ 25 ]

FAO

En 2010, la Organización para la Agricultura y la Alimentación ( FAO) Subcomité de acuicultura realizó las siguientes evaluaciones :

"La mayoría de los miembros pensaron que inevitable que la acuicultura se mueve lejos de la costa para que el mundo para satisfacer su creciente demanda de productos pesqueros e instaron al desarrollo de tecnologías apropiadas para su expansión y la asistencia a los países en desarrollo en el acceso a los [ ... ] Algunos miembros señalaron que la acuicultura también se puede desarrollar en alta mar en los grandes cuerpos de aguas continentales y la discusión debería extenderse a las aguas continentales , así [ ... ] Algunos miembros sugirieron cautela en relación con los posibles efectos negativos en el desarrollo de la acuicultura marina. [ 26 ]

El sub - comité recomendó la FAO " debería trabajar para clarificar la terminología técnica y jurídica relacionada con la acuicultura en alta mar con el fin de evitar la confusión ". [ 26 ]

Europa

En 2002 , la Comisión Europea emitió la siguiente declaración de política sobre la acuicultura : [ 27 ]

" Jaulas de peces deben moverse más lejos de la costa, y más investigación y desarrollo de tecnología marina en jaulas se deben promover con este fin . Experiencia desde fuera del sector de la acuicultura , por ejemplo, con las plataformas de petróleo , bien puede alimentar el sector de equipos de acuicultura , lo que permite ahorro en los costes de desarrollo de las tecnologías ".

Para el año 2008 , los sistemas marinos europeos operaban en Noruega, Irlanda , Italia, España , Grecia , Chipre , Malta , Croacia , Portugal y Libia [ 2 ] .

En Irlanda, como parte de su Plan Nacional de Desarrollo , se prevé que durante el período 2007-2013 , la tecnología asociada a los sistemas de acuicultura en alta mar se desarrollará , entre ellas: " Los sistemas de sensores para la alimentación , la biomasa y la vigilancia de la salud , control de alimentación , telemetría y comunicaciones [y] diseño de la jaula , los materiales, las pruebas estructurales y modelado ". [ 28 ]

Estados Unidos

Mover la acuicultura oceánica en la zona económica exclusiva (ZEE ) puede causar complicaciones con las regulaciones . En los Estados Unidos, el control reglamentario de los Estados costeros en general se extiende a 3 nm , mientras que las aguas federales (o ZEE ) se extienden a 200 mn de la costa . [ 8 ] Por lo tanto , la acuicultura offshore puede estar situado fuera del alcance de la ley estatal , pero dentro de la jurisdicción federal . [ 1 ] a partir de 2010 , " todos los centros comerciales de acuicultura han sido localizados en aguas cercanas a la costa de jurisdicción estatal o territorial ". [ 4 ] Sin embargo, " los procesos reguladores claros " y " las incertidumbres técnicas relacionadas con el trabajo en zonas de altura " han obstaculizado el progreso . [ 4 ] los cinco proyectos offshore de investigación y las operaciones comerciales en los EE.UU. - en Nueva Hampshire , Puerto Rico, Hawai y California - . están todos en las aguas federales [ 8 ] en junio de 2011 , se introdujo la Ley Nacional de Acuicultura Sostenible Marino de 2011 a la Cámara de Representantes " para establecer un sistema de regulación y el programa de investigación para la acuicultura oceánica sostenible en la zona económica exclusiva de Estados Unidos" . [ 29 ] [ 30 ]

Especies actuales

Para 2005, la acuicultura oceánica estuvo presente en 25 países, tanto como las granjas experimentales y comerciales . [ 5 ] La demanda del mercado significa que los esfuerzos agrícolas más offshore están dirigidos a elevar los peces . [ 8 ] Dos operaciones comerciales en los EE.UU. , y un tercero en las Bahamas están utilizando jaulas sumergibles para elevar alto valor peces carnívoros , tales como moi , cobia y pargo criollo . [ 1 ] jaulas sumergibles también están siendo utilizados en los sistemas experimentales para el halibut, abadejo , bacalao y platija de verano en las aguas de Nueva Hampshire , y para el jurel , corvina , pargo, pámpano , y cobia en el Golfo de México . [ 1 ]

La acuicultura marina de moluscos cultivados en sistemas de cultivo en suspensión, como vieiras y mejillones , está ganando terreno. Los sistemas de cultivo en suspensión incluyen procedimientos en los que los mariscos se cultivan en una cuerda atada o suspendidos de una balsa flotante en recipientes netos. [ 12 ] Mejillones , en particular, pueden sobrevivir a los altos niveles de estrés físicos que se producen en los entornos volátiles que se producen en las aguas de alta mar. Especies de peces deben alimentarse con regularidad, pero el marisco no , que pueden reducir los costos . [ 12 ] La Universidad de New Hampshire en los EE.UU. ha llevado a cabo investigaciones sobre el cultivo de mejillones azules sumergidos en un entorno de mar abierto . [ 31 ] Se han encontrado que cuando cultivado en las aguas menos contaminadas de la costa, [ 32 ] los mejillones se desarrollan más carne con cáscaras más ligeras. [ 31 ]

Status: E = Experimental, C = Commercial

Notes

1. Naylor, R., and Burke, M. (2005) "Aquaculture and ocean resources: raising tigers of the sea" Annual Review of Environmental Resources, 30:185–218.

2. Sturrock H, Newton R, Paffrath S, Bostock J, Muir J, Young J, Immink A and Dickson M (2008) Part 2: Characterisation of emerging aquaculture systems In: Prospective Analysis of the Aquaculture Sector in the EU, European Commission, EUR 23409 EN/2. ISBN 978-92-79-09442-2. doi:10.2791/31843

3. Black KD, Hansen PK and Holmer M (2004) Working Group Report on Benthic Impacts and Farm Siting In: Salmon Aquaculture Dialogue, WWF.

4. Upton, F. U., Buck, E. H. (2010) Open ocean aquaculture Congressional Research Service, CRS Report for Congress.

5. Skladany, M., Clausen, R., Belton, B. (2007) "Offshore aquaculture: the frontier of redefining oceanic property" Society and Natural Resources, 20: 169–176.

6. FAO. (2010) The State of World Fisheries and Aquaculture Rome. FAO, 2010, 197p.

7. Hanson, J. A. (Ed.) (1974) Open sea mariculture: Perspectives, problems and prospects. Stroudsburg, PA: Dowden, Hutchinson & Ross.

8. Rubino, Michael (Ed.) (2008) Offshore Aquaculture in the United States: Economic Considerations, Implications & Opportunities U.S. Department of Commerce; Silver Spring, MD; USA. NOAA Technical Memorandum NMFS F/SPO-103. 263p.

9. Stickney, R. R., Costa-Pierce, B., Baltz, D. M., Drawbridge, M., Grimes, C., Phillips, S., Swann, D. L. (2006) "Towards sustainable open ocean aquaculture in the United States" Fisheries, 31(12): 607–610.

10. Cressey, D. (2009) "Future fish". Nature, 458: 398–400.

11. Mann, C. C. (2004) "The bluewater revolution" Wired Mag. 12.05.

12. Lado-Insua, T., Ocampo, F. J., Moran, K. (2009) "Offshore mussel aquaculture: new or just renewed?" Oceans ’09 IEEE Bremen: Balancing Technology with Future Needs, art. No. 5278263.

13. Finfish aquaculture Atlantic Marine Aquaculture Center, University of New Hampshire. Retrieved 7 October 2011.

14. Carlsbad hatchery group proposes offshore aquaculture on oil platform North County Times, 19 June 2005.

15. Troell, M., Joyce, A., Chopin, T., Neori, A., Buschmann, A. H., Fang, J. (2009) "Ecological engineering in aquaculture – Potential for integrated multi-trophic aquaculture (IMTA) in marine offshore systems" Aquaculture, 297: 1–9.

16. Buck BH, Krause G and Rosenthal H (2004) "Extensive Open Ocean Aquaculture Development Within Wind Farms in Germany: The Prospect of Offshore Co-Management and Legal Constraints" Ocean & Coastal Management, 47: 95–122

17. Grimes J (1999) "Competition for Common Property Space: New Hampshire's Recreational and Open Ocean Aquaculture. Development" Proceedings of the 1999 Northeastern Recreation Research Symposium, GTR-NE-269, pp. 378–383.

18. Martinez-Cordero FJ (2007) "Socioeconomic Aspects of Species and Systems Selection for Sustainable Aquaculture" pp. 225–239. In: Leung P, Lee C and O'Bryen P (Eds.) Species and system selection for sustainable aquaculture, John Wiley & Sons. ISBN 978-0-8138-2691-2. doi:10.1002/9780470277867.ch30

19. Hoagland, P; Jin, D; Kite-Powell, H (2003). "The Optimal Allocation of Ocean Space: Aquaculture and Wild-Harvest Fisheries". Marine Resource Economics 18: 129–147. CiteSeerX: 10.1.1.121.1327.

20. Harte MJ, Campbell HV and Webster J (2010) "Looking for a safe harbor in a crowded sea: Coastal space use conflict and marine renewable energy development" In: Shifting Shorelines: Adapting to the Future,The 22nd International Conference of The Coastal Society.

21. Salmon Aquaculture Dialogue "State of Information" Reports WWF, 2004.

22. Simpson, S. (2011) "The blue food revolution" Scientific American, 304(2): 54–61. doi:10.1038/scientificamerican0211-54

23. Bekkevold, D., Hansen, M., Loeschcke, V. (2002) "Male reproductive competition in spawning aggregations of cod (Gardus morhua L.)" Molecular Ecology, 11: 91–102.

24. Walker, P. (2004) "Disease emergence and food security: global impact of pathogens on sustainable aquaculture production" Presented at Fish, Aquaculture and Food Security: Sustaining Fish as a Food Supply, Canberra, Australia.

25. Bostock J, Muir J, Young J, Newton R and Paffrath S (2008) Part 1: Synthesis report In: Prospective Analysis of the Aquaculture Sector in the EU, European Commission, EUR 23409 EN/1. ISBN 978-92-79-09441-5. doi:10.2791/29677

26. FAO (2010) Report of the fifth session of the sub-committee on aquaculture Report 950, Rome. ISBN 978-92-5-006716-2.

27. European Commission (2002) Communication from the Commission to the Council and the European Parliament – A Strategy for the Sustainable Development of European Aquaculture COM/2002/0511 Final, p.13.

28. Sea Change (2007–2013) Part II: Marine Foresight Exercise for Ireland p. 107. Marine Institute, Ireland.ISBN 1-902895-32-0.

29. National Sustainable Offshore Aquaculture Act of 2011 OpenCongress. Retrieved 17 Octobaer 2011.

30. New offshore aquaculture bill seeks to protect oceans Fis, 7 July 2011.

31. Shellfish aquaculture Atlantic Marine Aquaculture Center, University of New Hampshire. Retrieved 3 October 2011.

32. NOAA research harvests a sustainable way to farm the deep blue NOAA Magazine, Story 161. Retrieved 3 October 2011.

33. Aquaculture Collaborative Research Support Program p. 29. 2008. Twenty-Fifth Annual Technical Report. Aquaculture CRSP, Oregon State University, Corvallis, Oregon. Vol II, 288pp.

Further references

34. Lee C and O’Bryenn PJ (Eds.) (2007) Open Ocean Aquaculture—Moving Forward Oceanic Institute workshop, Hawaii Pacific University.

35. Nolan, Jean T (2009) Offshore Marine Aquaculture Nova Science. ISBN 978-1-60692-117-3.

36. Aquaculture in the United States NOAA. Updated 18 July 2011.

37. Stickney RR, Costa-Pierce B, Baltz DM, Drawbridge M, Grimes C, Phillips S and Swann DL (2006) Toward Sustainable Open Ocean Aquaculture in the United States Fisheries, 31 (12): 607–610.

38. Offshore Aquaculture NOAA. Updated 22 October 2007.

39. The National Offshore Aquaculture Act of 2007 NOAA. Updated 5 September 2008.

40. Government Accountability Office Report on Offshore Aquaculture NOAA. Updated 18 June 2008.

41. Mittal, Anu K. (2008) Offshore Marine Aquaculture: Multiple Administrative and Environmental Issues Need to be Addressed in Establishing a U.S. Regulatory Framework Diane Publishing. ISBN 978-1-4379-0567-0.

42. Obama admin hands offshore aquaculture oversight to NOAA New York Times, 23 April 2009.

43. Kapetsky JD and Aguilar-Manjarrez J (2007) Estimating open ocean aquaculture potential in EEZ with remote sensing and GIS: a reconnaissance In: Geographic information systems, remote sensing and mapping for the development and management of marine aquaculture, FAO fisheries technical paper 458. ISBN 978-92-5-105646-2.

44. Watson, L and Drumm A (2007) Offshore Aquaculture Development in Ireland, next steps FAO fisheries technical report.

45. James, Mark and Slaski, Richard (2007) Appraisal of the opportunity for offshore aquaculture in UK water CEFAS Finfish News, Issue 3.

46. Offshore Aquaculture: The Next Wave for Fish Farming? World Wildlife Fund. Retrieved 16 October 2011.

47. Offshore aquaculture viewpoints PBS. Retrieved 16 October 2011.

48. Open ocean aquaculture can be destructive Star Advertiser, 28 November 2010.

49. Ocean of trouble: Report warns of offshore fish farming dangers Grist, 12 October 2011.

Wild fisheries

Aquaculture and farmed fisheries

Aquaculture

Aquaculture engineering Aquaponics BAP Copper alloys in aquaculture Fisheries and aquaculture research institutes Geothermal energy and aquaculture Inland saline aquaculture Integrated multi-trophic aquaculture Mariculture Antimicrobials in aquaculture Offshore Organic Raceway

Biosecure KOI breeding and growing intensive facility in Israel.jpg

Fish farming

Broodstock Catfish Cobia Fish diseases and parasites Fish farming Fish feed Fish hatchery Fish stocking Spawning bed Salmon Tilapia Tailwater US hatcheries

Algaculture

Giant kelp Microalgae Microalgal bacterial flocs Photobioreactor Raceway pond Seaweed

Other species

Brine shrimp

Coral

Freshwater prawns

Hirudiculture

Marine shrimp

Octopus

Oysters

Scallops

Sea cucumber

Sea sponges

Turtles

By country

Alaska

Australia

Canada

Chile

China

New Zealand

South Africa

South Korea

OffShore aquaculture in USA

Twenty years ago, offshore aquaculture – fish and shellfish farming in U.S. federal waters – was an emerging technology with tremendous potential. The United States and other countries were at the forefront of an engineering and technology revolution, much like the old race to the moon. Bit by bit, scientists, engineers, and researchers began to figure out the “how” for this type of aquaculture. They developed dependable cage systems, remote feeders, monitoring systems, and broodstock for species that would thrive in the open ocean environment.

Every success fueled more interest. The potential for this type of seafood production was obvious – so were the challenges. Could this type of aquaculture be brought online safely as a way to complement wild harvest? Would it be economically viable? What about license to operate?

Offshore aquaculture

Some suitable offshore aquacultures fishes

Amberjack

Greater amberjack

Cobia

Aquaculture of cobia

Gilt-head bream 1

Red drum 1

Red snapper (fish)

Mangrove red snapper

Offshore aquaculture FAO report

ABSTRACT

This document contains the proceedings of the technical workshop entitled "Expanding mariculture farther offshore: technical, environmental, spatial and governance challenges" held from 22 to 25 March 2010, in Orbetello, Italy, and organized by the Aquaculture Branch of the Fisheries and Aquaculture Department of the Food and Agriculture Organization of the United Nations (FAO).

The objective of this workshop was to discuss the growing need to transfer land-based and coastal aquaculture production systems farther off the coast and provide recommendations for action to FAO, governments and the private sector. Offshore mariculture is likely to offer significant opportunities for food production and development to many coastal countries, especially in regions where the availability of land, nearshore space and freshwater are limited resources. The workshop report highlights the major opportunities and challenges for a sustainable mariculture industry to grow and further expand off the coast. Furthermore, it recommended that FAO should provide a forum through which the potential importance of the sea in future food production can be communicated to the public and specific groups of stakeholders and to support FAO Members and industry in the development needed to expand mariculture to offshore locations.

This CD–ROM publication includes the workshop report, six reviews covering technical, environmental, economic and marketing, policy and governance issues, and two case studies on highfin amberjack (Seriola rivoliana) offshore farming in Hawaii (the United States of America) and one on salmon farming in Chile. As an additional output derived from the workshop, FAO Fisheries and Aquaculture Technical Paper No. 549 entitled "A global assessment of offshore mariculture potential from a spatial perspective" is also included.

Basics

The basic production principles and technologies for off-the-coast and offshore mariculture remain, however, similar to those of modern coastal mariculture in terms of gear used (e.g. cages), use of dry feeds and selection of the farmed species. The choice of offshore farming sites may, on the other hand, be motivated by different economic drivers. Also, it may be anticipated that there will be a need for more automation and use of more sophisticated and remote-controlled feeding and monitoring systems, as well as the choice of species well suited for offshore mariculture conditions. The farming scale will probably be larger for offshore operations than that in coastal sites, possibly dictated by economic and operational reasons. It may also be speculated that the annual production for an offshore finfish farm could probably be higher than the largest off-the-coast salmon farms of today (e.g. 10 000 tonnes or 2.5 million 4 kg fish per year).

Offshore aquaculture cage

Legal aspects

In contrast to fisheries, there is no specialized body of international law dealing with mariculture. Mariculture is only incidentally affected by aspects of international law that were designed to deal with other issues. Mariculture can be affected by a number of provisions of general international law, such as the developing regime for the protection of the marine environment (Long, 2007) and by treaties. Many treaties create general obligations that can have an impact on state management over mariculture operations, e.g. the 1982 UNCLOS, which requires States to prevent, reduce or control pollution of the marine environment from a number of specified land-based sources (Percy, Hishamunda and Kuemlangan, 2013). Furthermore, many treaties, particularly those that deal with fisheries or the marine environment, can have repercussions on the development of mariculture activities. For example, the Convention for the Protection of the Marine Environment in the North-East Atlantic (OSPAR Convention) has a number of initiatives designed to minimize the impact of mariculture on the marine environment (Long, 2007). Also the 1992 Convention on Biological Diversity (CBD) has potential implications for mariculture (Wilson, 2004) together with codes of practice, whether voluntary or not, such as the FAO Code of Conduct for Responsible Fisheries (the Code) (FAO, 1995).

Este documento contiene las actas de la reunión técnica titulada " La expansión de la maricultura lejos de la costa : retos técnicos, ambientales , espaciales y de gobernabilidad ", celebrado del 22 al 25 marzo de 2010, en Orbetello , Italia, y organizado por la División de Acuicultura del Departamento de Pesca y Acuicultura de la Organización para la Agricultura y la Alimentación de las Naciones Unidas ( FAO).

El objetivo de este taller fue discutir la creciente necesidad de transferir los sistemas de producción basados en la tierra y de la acuicultura costera más lejos de la costa y ofrecer recomendaciones para la acción de la FAO , los gobiernos y el sector privado . Maricultura en mar abierto es probable que ofrecen importantes oportunidades para la producción y el desarrollo de alimentos para muchos países costeros , especialmente en las regiones donde la disponibilidad de tierra , el espacio cercano a la costa y el agua dulce son recursos limitados. El informe del taller se destacan las principales oportunidades y desafíos para la industria de la maricultura sostenible para crecer y ampliar aún más cerca de la costa . Además, recomendó que la FAO debería proporcionar un foro a través del cual la potencial importancia del mar en el futuro la producción de alimentos puede ser comunicada a los grupos públicos y particulares de las partes interesadas y para apoyar a los Miembros de la FAO y de la industria en el desarrollo necesario para ampliar la maricultura en destinos internacionales .

Esta publicación en CD- ROM incluye el informe del taller , seis exámenes que cubren

Aspectos legales

En contraste con la pesca, no existe un organismo especializado de la ley internacional sobre maricultura. La maricultura es sólo incidentalmente afectada por aspectos del derecho internacional que se han diseñado para hacer frente a otras cuestiones. La maricultura puede verse afectada por una serie de disposiciones del derecho internacional general , tales como el régimen de desarrollo para la protección del medio marino (Long, 2007) y por los tratados. Muchos tratados crean obligaciones generales que pueden tener un impacto en la gestión del Estado sobre las actividades de maricultura , por ejemplo, la UNCLOS 1982 , que obliga a los Estados a prevenir, reducir o controlar la contaminación del medio marino procedente de un número de fuentes terrestres especificadas ( Percy, Hishamunda y Kuemlangan , 2013 ) . Por otra parte, muchos tratados , en particular las que se ocupan de la pesca o el medio ambiente marino , pueden tener repercusiones en el desarrollo de las actividades de maricultura . Por ejemplo , la Convención para la Protección del Medio Ambiente Marino del Atlántico del Nordeste ( Convenio OSPAR) tiene una serie de iniciativas destinadas a minimizar el impacto de la maricultura sobre el medio marino (Long, 2007 ) . También el Convenio de 1992 sobre la Diversidad Biológica ( CDB) tiene implicaciones potenciales para la maricultura (Wilson, 2004 ), junto con los códigos de práctica , ya sea voluntaria o no, tales como el Código de Conducta para la Pesca Responsable (el Código) (FAO, 1995 )

Environmental risks of offshore aquaculture

Lovatelli, A., Aguilar-Manjarrez, J. & Soto, D. eds. 2013. CD–ROM. New edition, expanded. Expanding mariculture farther offshore – Technical, environmental, spatial and governance challenges. FAO Technical Workshop. 22–25 March 2010. Orbetello, Italy. FAO Fisheries and Aquaculture Proceedings No. 24. Rome, FAO.

-*-

Aquaculture species

Cobia

The cobia (Rachycentron canadum) is a species of perciform marine fish, the only representative of the genus Rachycentron and the family Rachycentridae. Other common names include black kingfish, black salmon, ling, lemonfish, crabeater, prodigal son and aruan tasek.

Attaining a maximum length of 2 m (78 in) and maximum weight of 78 kg (172 lb), the cobia has an elongated fusiform (spindle-shaped) body and a broad, flattened head. The eyes are small and the lower jaw projects slightly past the upper. Fibrous villiform teeth line the jaws, the tongue, and the roof of the mouth. The body of the fish is smooth with small scales. It is dark brown in color, grading to white on the belly with two darker brown horizontal bands on the flanks. The stripes are more prominent during spawning, when they darken and the background color lightens.

The large pectoral fins are normally carried horizontally, perhaps helping the fish attain the profile of a shark. The first dorsal fin has six to 9 independent, short, stout, sharp spines. The family name Rachycentridae, from the Greek words rhachis ("spine") and kentron ("sting"), was inspired by these dorsal spines. The mature cobia has a forked, slightly lunated tail, which is usually dark brown. The fish lacks a swim bladder. The juvenile cobia is patterned with conspicuous bands of black and white and has a rounded tail. The largest cobia taken on rod and reel came from Shark Bay, Australia, and weighed 60 kg (135 lb).

Similar species

The cobia resembles its close relatives, the remoras of the family Echeneidae. It lacks the remora's dorsal sucker and has a stouter body.

Distribution and habitat

Cobia fingerlings in at the University of Miami (Photo D. Benetti)

Female broodstock, about 8 kg, prior to transport to broodstock holding tanks at the University of Miami (photo D. Benetti)

Cobia on ice at Open Blue Sea Farms (photo Brian O'Hanlon)

The cobia is normally solitary except for annual spawning aggregations, and sometimes it will congregate at reefs, wrecks, harbours, buoys, and other structural oases. It is pelagic, but it may enter estuaries and mangroves in search of prey.

It is found in warm-temperate to tropical waters of the West and East Atlantic Ocean, throughout the Caribbean, and in the Indo-Pacific off India, Australia and Japan.[1] It is eurythermal, tolerating a wide range of temperatures, from 1.6 to 32.2°C. It is also euryhaline, living at salinities of 5 to 44.5 ppt.[2]

Ecology

The cobia feeds primarily on crabs, squid, and fish. It will follow larger animals such as sharks, turtles, and manta rays to scavenge. It is a very curious fish, showing little fear of boats.

The predators of the cobia are not well documented, but the mahi-mahi (Coryphaena hippurus) is known to feed on juveniles and the shortfin mako shark (Isurus oxyrinchus) eats the adult.

The cobia is frequently parasitized by nematodes, trematodes, cestodes, copepods, and acanthocephalans.

Life history

The cobia is a pelagic spawner, releasing many tiny (1.2 mm), buoyant eggs into the water, where they become part of the plankton. The eggs float freely with the currents until hatching. The larvae are also planktonic, being more or less helpless during their first week until the eyes and mouths develop. The male matures at two years and the female at three years. Both sexes lead moderately long lives of 15 years or more. Breeding activity takes place diurnally from April to September in large offshore congregations, where the female is capable of spawning up to 30 times during the season.[3]

Migration

The cobia makes seasonal migrations. It winters in the Gulf of Mexico, then moves north as far as Maryland for the summer, passing Florida around March.

Human uses

The cobia is sold commercially and commands a relatively high price for its firm texture and excellent flavor. However, no designated wild fishery exists because it is a solitary species. It has been farmed in aquaculture. The flesh is usually sold fresh. It is typically served in the form of grilled or poached fillets. Chefs Jamie Oliver and Mario Batali each cooked several dishes made with cobia in the "Battle Cobia" episode of the Food Network program Iron Chef America, which first aired in January, 2008. Thomas Keller's restaurant, The French Laundry, has offered cobia on its tasting menu.[4]

Aquaculture

Aquaculture of cobia

This fish is considered to be one of the most suitable candidates for warm, open-water marine fish aquaculture in the world.[5][6] Its rapid growth rate and the high quality of the flesh could make it one of the most important marine fish for future aquaculture production.[7]

Currently, the cobia is being cultured in nurseries and offshore grow-out cages in parts of Asia, the United States, Mexico, and Panama. In Taiwan, cobia of 100 to 600 g are cultured for 1.0 to 1.5 years until they reach 6 to 8 kg. They are then exported to Japan, China, North America, and Europe. Around 80% of marine cages in Taiwan are devoted to cobia culture.[6] In 2004, the FAO reported that 80.6% of the world's cobia production was in China and Taiwan.[8] Vietnam is the third-largest producer, yielding 1,500 tonnes in 2008.[6] Following the success of cobia aquaculture in Taiwan, emerging technology is being used to demonstrate the viability of hatchery-reared cobia in collaboration with the private sector at exposed offshore sites in Puerto Rico and the Bahamas, and the largest open ocean farm in the world is run by a company called Open Blue off the coast of Panama.[9]

Greater depths, stronger currents, and distance from shore all act to reduce environmental impacts often associated with finfish aquaculture. Offshore cage systems could become a more environmentally sustainable method for commercial marine fish aquaculture.[10] However, some problems still exist in cobia culture, including high mortality due to stress during transfer from nursery tanks or inshore cages to the offshore grow-out cages, as well as disease.[6]

Spanish

La cobia ( Rachycentron canadum ) es una especie de peces marinos perciformes , el único representante del género Rachycentron y la familia Rachycentridae . Otros nombres comunes incluyen pez rey negro , salmón negro , maruca , Lemonfish , cangrejera , el hijo pródigo y Tasek Aruan .

Alcanza una longitud máxima de 2 m ( 78 pulgadas) y un peso máximo de 78 kg (172 lb), la cobia tiene un cuerpo alargado fusiforme ( forma de huso ) y una amplia y aplanada cabeza. Los ojos son pequeños y los proyectos de la mandíbula inferior ligeramente más allá de la parte superior . Dientes viliformes fibrosos se alinean en las mandíbulas, la lengua y el techo de la boca. El cuerpo de los peces es suave con pequeñas escalas . Es de color marrón oscuro , de clasificación de blanco en el vientre , con dos bandas horizontales marrones más oscuras en los flancos . Las rayas son más prominentes durante el desove , cuando oscurece y aclara el color de fondo .

Las grandes aletas pectorales que normalmente se llevan en posición horizontal, tal vez ayudan a los peces alcanzan el perfil de un tiburón. La primera aleta dorsal tiene de seis a 9 espinas afiladas independientes , cortos , gruesos . El nombre de la familia Rachycentridae , de las palabras griegas raquis ( " columna vertebral ") y Kentron ( " aguijón ") , fue inspirado por estas espinas dorsales. La cobia madura tiene una forma de horquilla , cola ligeramente lunada , que es generalmente de color marrón oscuro . El pez carece de vejiga natatoria . La cobia menores está modelada con bandas visibles de blanco y negro y tiene una cola redondeada. El más grande de cobia taken on caña y carrete vino de Shark Bay , Australia , y pesaba 60 kg ( 135 libras ) .

Especies similares

La cobia se parece a sus parientes cercanos, las rémoras de la familia Echeneidae . Carece de lechón dorsal de la rémora y tiene un cuerpo más robusto .

Distribución y hábitat

Alevines Cobia en la Universidad de Miami (Foto D. Benetti )

Reproductor hembra de unos 8 kg antes de transportarse a tanques de retención en la Universidad de Miami ( foto D. Benetti )

Cobia en el hielo en el Open Blue Sea Farms ( foto Brian O'Hanlon )

La cobia es normalmente solitaria excepto para las agregaciones de desove anuales , y en ocasiones se congregan en los arrecifes , naufragios , puertos, boyas y otros oasis estructurales. Es pelágico, pero puede entrar en los estuarios y manglares en busca de presas .

Se encuentra en las cálidas aguas templadas y tropicales del oeste y del este del Océano Atlántico, en el Caribe , y en el Indo- Pacífico frente a la India, Australia y Japón. [ 1 ] Es euriterma , tolerar un amplio rango de temperaturas , desde 1,6 a 32,2 ° C. También es eurihalino , viviendo en salinidades de 5 a 44,5 por mil. [ 2 ]

Ecología

La cobia se alimenta principalmente de cangrejos , calamares y peces. Seguirá los animales más grandes, como los tiburones , tortugas y manta rayas para barrer . Es un pez muy curioso , mostrando poco temor de los barcos.

Los depredadores de la cobia no están bien documentados , pero el mahi -mahi ( Coryphaena hippurus ) se sabe que se alimentan de los juveniles y el tiburón marrajo ( Isurus oxyrinchus ) come el adulto .

La cobia es frecuentemente parasitada por nematodos , trematodos , cestodos , copépodos, y acantocéfalos .

Historia de vida o historia natural

La cobia es un desovante pelágico , la liberación de muchos huevos pequeños ( 1,2 mm ) , flotantes en el agua, donde se convierten en parte del plancton . Los huevos flotan libremente con las corrientes hasta la eclosión . Las larvas también son planctónicas , siendo más o menos indefensas durante su primera semana hasta que los ojos y la boca se desarrollan. El macho madura sexualmente a los dos años y la hembra a los tres años . Ambos sexos pueden tener moderadamente largas vida de 15 años o más. La actividad reproductiva tiene lugar diurnamente de abril a septiembre, en grandes congregaciones en alta mar , donde la hembra es capaz de desove hasta 30 veces durante la temporada. [ 3 ]

Migración

La cobia hace migraciones estacionales . Pasa el invierno en el Golfo de México , y luego se mueve hacia el norte hasta Maryland para el verano, que pasa de la Florida alrededor de marzo.

Uso humano

La cobia se vende en el mercado y tiene un precio relativamente alto por su textura firme y un sabor excelente . Sin embargo , no existe una pesca silvestre designada , ya que es una especie solitaria . Se ha cultivado en acuicultura. La carne se vende generalmente fresco. Por lo general se sirve en forma de filetes a la parrilla o escalfados . Chefs Jamie cada cocidos varios platos elaborados con cobia en el episodio " Batalla Cobia " del programa de Food Network Iron Chef America , que se estrenó en enero de 2008. Restaurante de Thomas Keller , The French Laundry Oliver y Mario Batali , ha ofrecido cobia en su menú de degustación. [ 4 ]

Acuicultura

La acuicultura de la cobia

Este pescado es considerado como uno de los candidatos más idóneos para que se caliente , en aguas abiertas de la acuicultura de peces marinos en el mundo . [ 5 ] [ 6 ] Su rápida tasa de crecimiento y la alta calidad de la carne podrían hacer que sea uno de los más importantes peces marinos para la futura producción de la acuicultura . [ 7 ]

En la actualidad, la cobia está siendo cultivado en viveros y en alta mar las jaulas de engorde en algunas partes de Asia, los Estados Unidos , México y Panamá . En Taiwán, la cobia de 100 a 600 g se cultivan durante 1,0 a 1,5 años hasta que alcanzan entre 6 y 8 kg . A continuación, se exportan a Japón , China , América del Norte y Europa. Alrededor del 80 % de las jaulas marinas en Taiwan se dedican a cultivo de cobia . [ 6 ] En 2004, la FAO informó que el 80,6 % de la producción de cobia en el mundo estaba en China y Taiwán. [ 8 ] Vietnam es el tercer mayor productor , produciendo 1500 de toneladas en 2008 . [ 6 ] Tras el éxito de la acuicultura cobia en Taiwán, tecnología emergente está siendo utilizado para demostrar la viabilidad de la cobia de criadero en colaboración con el sector privado en los sitios marinos expuestos en Puerto Rico y las Bahamas , y el mayor granja océano abierto en el mundo está dirigido por una compañía llamada Abrir azul de la costa de Panamá . [ 9 ]

Mayores profundidades , corrientes fuertes y distancia a la costa todos actúan para reducir los impactos ambientales asociados a menudo a la acuicultura de peces . Sistemas de jaulas en alta mar podría convertirse en un método más ecológicamente sostenible para la acuicultura de peces marinos comerciales. Sin embargo , aún existen [ 10 ] algunos problemas en el cultivo de cobia , incluyendo una alta mortalidad debido a la tensión durante la transferencia de los tanques de viveros o jaulas costeras a las jaulas marinas de engorde , así como la enfermedad . [ 6 ]

Timeline

References/Referencias de cobia

Ditty, J. G. & Shaw, R. F. 1992. Larval development, distribution, and ecology of cobia Rachycentron canadum (Family: Rachycentridae) in the northern Gulf of Mexico. Fishery Bulletin, 90:668-677

Resley, M. J., Webb, K. A. & Holt, G. J. 2006. Growth and survival of juvenile cobia Rachycentron canadum cultured at different salinities in recirculating aquaculture systems. Aquaculture, 253:398-407.

Brown-Peterson, N. J., Overstreet, R. M., Lotz, J. M. 2001. Reproductive biology of cobia, Rachycentron canadum, from coastal waters of the southern United States. Fish. Bull. 99:15-28

French Laundry menu, September 2011

Kaiser, J.B. & Holt, G.J. 2004. Cobia: a new species for aquaculture in the US. World Aquaculture, 35:12-14.

Liao, I.C., Huang, T.S., Tsai, W.S., Hsueh, C.M., Chang, S.L. & Leano, E.M. 2004. Cobia culture in Taiwan: current status and problems. Aquaculture, 237:155-165.

Nhu, V. C., Nguyen, H. Q., Le, T. L., Tran, M. T., Sorgeloos, P., Dierckens, K., Reinertsen H., Kjorsvik, E. & Svennevig, N. 2011. Cobia Rachycentron canadum aquaculture in Vietnam: recent developments and prospects. Aquaculture 315:20-25.

FAO

Benetti, D. D., et al. 2007. Aquaculture of cobia (Rachycentron canadum) in the Americas and the Caribbean. RSMAS, p. 1-21.

Benetti, D.D., et al. 2003. Advances in hatchery and growout technology of marine finfish candidate species for offshore aquaculture in the Caribbean. Proceedings of the Gulf and Caribbean Fisheries Institute, 54:475-487.

Red drum

The red drum (Sciaenops ocellatus), also known as channel bass, redfish, spottail bass or simply reds, is a game fish that is found in the Atlantic Ocean from Massachusetts to Florida and in the Gulf of Mexico from Florida to Northern Mexico.[1] It is the only species in the genus Sciaenops. The red drum is a cousin to the black drum (Pogonias cromis), and the two species are often found in close proximity to each other; they can interbreed and form a robust hybrid, and younger fish are often indistinguishable in flavor.[2]

Red drum are a dark red color on the back, which fades into white on the belly. The red drum have a characteristic eyespot near the tail and are somewhat streamlined. Three year-old red drum typically weigh six to eight pounds. When they are near or over twenty-seven inches, they are called “bull reds”. The largest red drum on record weighed just over 94 pounds and was caught in 1984 on Hatteras Island. Red drum are relatives of the black drum and both make a croaking or drumming sound when distressed.

The most distinguishing mark on the red drum is one large black spot on the upper part of the tail base. Having multiple spots is not uncommon for this fish but having no spots is extremely rare. As the fish with multiple spots grow older they seem to lose their excess spots. Scientists believe that the black spot near their tail helps fool predators into attacking the red drum's tail instead of their head, allowing the red drum to escape.[3] The red drum uses its senses of sight and touch, and its downturned mouth, to locate forage on the bottom through vacuuming or biting. On the top and middle of the water column, it uses changes in the light that might look like food. In the summer and fall, adult red drum feed on crabs, shrimp, and sand dollars, in the spring and winter, adults primarily feed on menhaden, mullet, pinfish, sea robin, lizardfish, spot, Atlantic croaker, and flounder.

Distribution

Red drum naturally occur along the southern Atlantic and Gulf of Mexico coasts of the United States, including the coasts of Louisiana, Texas, Alabama, Mississippi, and Florida. Aquaculture activities involving Red Drum occur around the world.[4] Immature red drum prefer grass marsh areas of bays and estuaries when available. Both younger mature red drum (3-6 years of age) and bull red drum prefer rocky outcroppings including jetties and manmade structures, such as oil rigs and bridge posts. Around this type of structure, they are found throughout the water column.

Reproduction and growth

Weight vs. length for red drum (data from Jenkins 2004).

Mature red drum spawn in near shorelines from mid-August to mid-October.[5] The red drum's eggs incubate for 24 hours. A female lays about 1.5 million (with a range of 200,000 up to more than three million) eggs per batch. Scharf (2000) reported that in the first year, young red drum in Texas estuaries grew about 0.6 mm per day, though the rates varied with location and year and were higher in more southerly estuaries.[6] After the first year they may be 271 – 383 mm long. About half of red drum are able to reproduce by age 4 years, when they are 660-700 mm long and 3.4 – 4 kg in weight. Red drum live to be 60 years old unless caught.

50.5 inches red drum caught in May 19 2010

Adults mature by 3 – 5 years of age; approximate length at maturity: males – 28 inches, females – 33 inches.

Spawn during late summer and fall. Spawning aggregations occur near estuary inlets and passes along barrier island beaches. Males produce drumming sounds using muscular contractions to vibrate the swimbladder, to attract females.

Larval red drum use vertical migrations to ride high salinity tidal currents into tidal creeks and shallow salt marsh nursery habitats. [7]

As red drum grow longer, they increase in weight. The relationship between length and weight is not linear. The relationship between length (L) and weight (W) for nearly all species of fish can be expressed by an equation of the form:

W = aL^b\!\,

Invariably, b is close to 3.0 for all species, and a varies between species. Jenkins (2004)[8] reported slightly different weight-length relationships for red drum caught in the spring and the fall off the western Gulf Coast of Louisiana:

Spring: W = 0.000005297L^{3.110}\!\,

Fall: W = 0.000015241L^{2.94}\!\,

where weight is in grams and length is total length measured in millimeters. For example, these relationships predict that a 600 mm red drum (just under two feet long) would weigh about 2300 grams (just over five pounds). These relationships can be used more specifically to determine how healthy a sample of red drum are by comparing their actual weights to weights predicted by these relationships for the same length.

Consumption

Redfish was named as giving a good result with court-bouillon in a cookbook published in New Orleans in 1901.[9]

In the early 1980s, the chef Paul Prudhomme made his dish of Cajun-style blackened redfish (red drum) popular. When catches of redfish declined in the 1980s many believed that it was being commercially over-fished because of its recent popularity. However, redfish numbers started declining in the late 1970s, possibly because of over-fishing of young redfish in shallow coastal waters by recreational fishermen.[citation needed]

On March 1, 2009 redfish was the "secret ingredient" on the television program Iron Chef America, with competitors Mourad Lahlou and Cat Cora both preparing several dishes from the fish.

Red drum have a moderate flavor and are not oily. Big drum can be challenging to clean; removing the large scales can be challenging. Many fishers prefer to fillet with an electric knife, first removing the fillet from along the backbone, and then using the electric knife to cut the fillet from the skin and scales. Fish over 15 lbs can become tough and have a consistency comparable with chicken, rather than the flakey texture of many species of fish. Younger fish are often indistinguishable in flavor from black drum.[10]

Commercial and recreational use

From 1980 through 1988, commercial fishermen took an average of 28% of the redfish while sport fishermen harvested 72 percent. Catch limits and size restrictions have increased the average weight of redfish caught in Louisiana coastal waters.[11] Restrictions on both sport and commercial fishermen allowed the species to rebuild. States actively vary the recreational catch limits and minimum and maximum lengths in order to help maintain sustainable red drum populations. Executive Order 13449 of October 20, 2007, issued by U.S. President George W. Bush, designated the red drum as a protected game fish. The order prohibits sale of red drum caught in Federal waters and encourages states to consider designating red drum as a protected game fish within state waters.[12] While they may no longer be commercially harvested in U.S. federal waters or in most state waters, they are readily caught and still enjoyed as table fare by many. In addition, farm raised redfish are still available as a commercial product [13] Commercial netting disappeared after coastal states like Florida declared red drum prohibited for sale. Recreational size and bag limits have been highly effective, allowing daily limits to be increased in recent years.

Relationship to humans

The North Carolina General Assembly of 1971 designated the red drum as the official State Salt Water Fish. (Session Laws, 1971, c. 274; G.S. 145-6).[14]

Spanish

Corvina capturada en Cape Fear por la hija de Bill Drewer

El tambor rojo o corvina ( Sciaenops ocellatus ) , también conocido como el bajo de canal , la gallineta , el bajo spottail o simplemente rojos, es un pescado que se encuentra en el océano Atlántico desde Massachusetts a Florida y en el Golfo de México desde Florida hasta el norte de México . [ 1 ] es la única especie en el género Sciaenops . La corvina es un primo al tambor negro ( Pogonias cromis ) , y las dos especies a menudo se encuentran en las proximidades de uno al otro ; que pueden cruzarse y forman un híbrido robusto , y los peces más pequeños son a menudo indistinguibles en sabor . [ 2 ]

Tambor rojo son de un color rojo oscuro en la parte de atrás , que se desvanece en blanco en el vientre . El tambor rojo tiene una mancha ocular característica cerca de la cola y son algo aerodinámico. Tambor rojo de tres años de edad, por lo general pesan entre seis y ocho libras. Cuando están cerca o encima de veintisiete pulgadas , son llamados "rojos del toro " . El tambor más grande roja en el expediente pesaba poco más de 94 libras y fue capturado en 1984 en Hatteras Island. Tambor rojo son parientes del tambor negro y ambos hacen un sonido ronco o tambores cuando angustiado.

La marca más distintiva en el tambor rojo es un gran punto negro en la parte superior de la base de la cola . Tener múltiples puntos no es raro que este pez , pero al no tener puntos es extremadamente rara. Como los peces con múltiples manchas crecen, parecen perder su exceso de manchas . Los científicos creen que el punto negro cerca de su cola ayuda depredadores tonto para que atacara a la cola del tambor rojo en lugar de su cabeza, permitiendo que el tambor rojo para escapar . [ 3 ] El tambor rojo usa sus sentidos de la vista y el tacto , y su boca vuelta hacia abajo , para localizar el forraje en la parte inferior a través de la aspiradora o morder. En el alto y medio de la columna de agua , utiliza los cambios en la luz que podría ser como la comida. En el verano y otoño , adulto alimento tambor rojo en cangrejos , camarones, y los dólares de arena , en la primavera y el invierno , los adultos se alimentan principalmente de lacha , salmonete, pinfish , petirrojo de mar, pez lagarto , punto, Atlántico corvina y lenguado .

Distribución

Tambor rojo produce de forma natural a lo largo del sur del Atlántico y el Golfo de México costas de los Estados Unidos, incluyendo las costas de Luisiana, Texas, Alabama, Mississippi y Florida. Las actividades de acuicultura que implican Red Drum se producen en todo el mundo . [ 4 ] tambor rojo inmaduro prefieren hierba zonas pantanosas de bahías y estuarios cuando esté disponible . Tanto tambor más joven madura roja ( 3-6 años de edad ) y el tambor rojo toro prefieren afloramientos rocosos , incluyendo muelles y estructuras hechas por el hombre , tales como plataformas petroleras y puestos de puente . Alrededor de este tipo de estructura , se encuentran toda la columna de agua.

Reproducción y crecimiento

Peso función de la longitud de la corvina roja (datos de Jenkins 2004 ) .

Spawn tambor rojo madura en cerca de las costas de mediados de agosto a mediados de octubre. [ 5 ] Huevos del tambor rojo incubar durante 24 horas. Una hembra pone alrededor de 1,5 millones ( con un rango de 200.000 hasta más de tres millones ) huevos por lote . Scharf ( 2000 ) informó que en el primer año , tambor rojo joven en los estuarios de Texas creció alrededor de 0,6 mm por día , aunque las tasas varían con la ubicación y el año y fueron superiores en los estuarios más al sur . [ 6 ] Después del primer año pueden ser 271-383 mm de largo. Aproximadamente la mitad de tambor rojo son capaces de reproducirse por 4 años de edad , cuando son 660 a 700 mm de largo y 3,4-4 kg de peso. Tambor Red vivir hasta los 60 años de edad a no ser atrapado .

Adultos maduros por 3 - 5 años de edad; longitud aproximada en la madurez : hombres - 28 pulgadas, las hembras - 33 pulgadas .

Desovar a finales de verano y otoño. Agregaciones reproductivas ocurren cerca de las entradas de los estuarios y pasa a lo largo de las playas de islas de barrera . Los machos producen sonidos de tambores mediante contracciones musculares para hacer vibrar la vejiga natatoria , para atraer a las hembras.

Tambor rojo larval utilizar migraciones verticales para montar alta salinidad corrientes de marea en canales de marea y la sal superficial pantano hábitats de crianza . [ 7 ]

Como tambor rojo crezca más , que aumentan de peso. La relación entre la longitud y el peso no es lineal . La relación entre la longitud (L ) y el peso ( W ) para casi todas las especies de peces se puede expresar mediante una ecuación de la forma:

W = aL ^ b \! \ ,

Invariablemente , b está cerca de 3.0 para todas las especies , y varía entre las especies . Jenkins ( 2004 ) [ 8 ] reportaron ligeramente diferentes relaciones peso-talla para tambor rojo capturado en la primavera y el otoño en la costa oeste del Golfo de Louisiana :

Primavera : W = 0.000005297L ^ { 3.110 } \ \ ,

Otoño : W = 0.000015241L ^ { 2,94 } \ \ ,

donde el peso es en gramos y la longitud es la longitud total medido en milímetros. Por ejemplo , estas relaciones predicen que un tambor rojo 600 mm ( algo menos de dos pies de largo ) pesaría alrededor de 2300 gramos ( poco más de cinco libras). Estas relaciones se pueden utilizar más específicamente a determinar qué tan saludable es una muestra de tambor rojo están comparando sus pesos reales a pesos predichos por esas relaciones de la misma longitud.

Consumo

Gallineta nórdica fue nombrado como dar un buen resultado con la corte de caldo en un libro de cocina publicado en Nueva Orleans en 1901. [ 9 ]

A principios de la década de 1980 , el chef Paul Prudhomme hizo su plato de estilo Cajun gallineta ennegrecido (tambor rojo) popular. Cuando las capturas de gallineta nórdica disminuyeron en la década de 1980 muchos creían que estaba siendo comercialmente sobreexplotadas debido a su reciente popularidad . Sin embargo , los números de gallineta empezaron a bajar a finales de 1970 , posiblemente a causa de la pesca excesiva de los jóvenes gallineta nórdica en aguas costeras poco profundas por los pescadores recreativos . [ Cita requerida ]

El 01 de marzo 2009 gallineta nórdica era el " ingrediente secreto " en el programa de televisión Iron Chef America , con los competidores Mourad Lahlou y Cat Cora tanto preparar varios platos de pescado .

Tambor rojo tiene un sabor moderado y no son grasas. Bombo puede ser difícil de limpiar; la eliminación de las grandes escalas puede ser un reto . Muchos pescadores prefieren filete con un cuchillo eléctrico , eliminando primero el filete de a lo largo de la columna vertebral , y luego usando el cuchillo eléctrica para cortar el filete de la piel y escamas . Pescados sobre 15 libras puede volverse áspera y tener una consistencia comparable con pollo , en lugar de la textura escamosa de muchas especies de peces. Los peces más jóvenes son a menudo indistinguibles en sabor de tambor negro . [ 10 ]

Uso comercial y recreativo

Desde 1980 hasta 1988 , los pescadores comerciales tuvieron un promedio de 28 % de la gallineta nórdica , mientras que los pescadores deportivos cosechados el 72 por ciento . Límites de captura y restricciones de tamaño han aumentado el peso medio de gallineta nórdica capturadas en las aguas costeras de Louisiana . [ 11 ] Las restricciones a los pescadores deportivos y comerciales permitieron la especie a la reconstrucción. Los estados varían de forma activa los límites de captura de recreo y mínimo y longitudes máximas con el fin de ayudar a mantener las poblaciones de tambor rojo sostenibles. La Orden Ejecutiva 13449 del 20 de octubre de 2007, emitida por el presidente de EE.UU., George W. Bush , designó el tambor rojo como un pescado protegido. La orden prohíbe la venta de tambor rojo capturado en aguas federales y alienta a los Estados a considerar la designación de tambor rojo como la pesca deportiva en las aguas protegidas del Estado. [ 12 ] Mientras que pueden no ser cosechadas comercialmente en aguas de jurisdicción federal de los Estados Unidos o en la mayoría de las aguas del estado , que son capturados fácilmente y disfrutado como tabla de tarifas por muchos todavía . Además , criadero gallineta están todavía disponibles como un producto comercial [ 13 ] red comercial desapareció después de los estados costeros como Florida declarado tambor rojo prohibidos para la venta. Los límites de tamaño de recreo y bolsa han sido muy eficaz , permitiendo que los límites diarios para aumentar en los últimos años.

Relación a los seres humanos

La Asamblea General de Carolina del Norte de 1971 designa el tambor rojo como la oficial del Estado Pez de agua salada . ( Leyes de Sesión de 1971, c 274 ; . G.S. 145-6 ) [ 14 ] .

Notes/Referencias

1. Sciaenops ocellatus, Froese, R. and D. Pauly. Editors. 2009.FishBase. World Wide Web electronic publication. www.fishbase.org, version (07/2009). http://www.fishbase.org/Summary/SpeciesSummary.php?id=425

2. A Comparison of Black Drum, Red Drum, and their Hybrid in Saltwater Pond Culture Anne Henderson-Arzapalo, Robert L. Colura, Anthony F. Maciorowski, Journal of the World Aquaculture Society Volume 25 Issue 2, Pages 289 - 296

3. Smithsonian Marine Station page on red drum

4. Peters Life History of Red Drum Peters, K.M., McMichael Jr., R. H. Florida Department of Natural Resources Bureau of Marine Research, St. Petersburg, Florida.

5. Wilson and Nieland, 1994

6. Scharf 2000

7. Wenner C. 1999. Red Drum: natural history and fishing techniques in South Carolina. Marine Resources Research Institute, Marine Resources Division, SC Department of Natural Resources, Charleston, SC. 40 pp.

8. Jenkins, J.A. Fish bioindicators of ecosystem condition at the Calcasieu Estuary, Louisiana. National Wetlands Research Center, USGS, Open-File Report 2004-1323, 2004

9. Anonymous. (1901). "The Original Picayune Creole Cook Book." New Orleans: Times-Picayune Publishing Corporation. (reprinted 1906, 1916, 1922, 1928, 1936, 1938, 1942, 1945, 1947, 1954, 1966, 1971.)

10. A Comparison of Black Drum, Red Drum, and their Hybrid in Saltwater Pond Culture Anne Henderson-Arzapalo, Robert L. Colura, Anthony F. Maciorowski, Journal of the World Aquaculture Society Volume 25 Issue 2, Pages 289 - 296

11. Understanding Redfish Biology - accessed August 6, 2009

12. "Executive Order 13449: Protection of Striped Bass and Red Drum Fish Populations". Office of the Federal Register. October 20, 2007. Retrieved October 24, 2007.

13. Fritcheey, Robert (1994). Wetland Riders. Golden Meadow, Louisiana: New Moon Press.

14. Official State Symbols of North Carolina

Northern Red Snapper

The northern red snapper, Lutjanus campechanus, is a species of snapper native to the western Atlantic Ocean including the Gulf of Mexico, where it inhabits environments associated with reefs. This species is commercially important and is also sought-after as a game fish.[1]

The northern red snapper's body is very similar in shape to other snappers, such as the mangrove snapper, mutton snapper, lane snapper, and dog snapper. All feature a sloped profile, medium-to-large scales, a spiny dorsal fin, and a laterally compressed body. Northern red snapper have short, sharp, needle-like teeth, but they lack the prominent upper canine teeth found on the mutton, dog, and mangrove snappers. This snapper reaches maturity at a length of about 39 cm (15 in). The common adult length is 60 cm (24 in), but may reach 100 cm (39 in). The maximum published weight is 22.8 kg (50 lb), and the oldest reported age is 57 years.[1] Coloration of the northern red snapper is light red, with more intense pigment on the back. It has 10 dorsal spines, 14 soft dorsal rays, three anal spines and eight to 9 anal soft rays. Juvenile fish (shorter than 30–35 cm) can also have a dark spot on their sides, below the anterior soft dorsal rays, which fades with age.[1]

Distribution

Pargo L. campechanus, from the Gulf of Mexico

The northern red snapper is found in the Gulf of Mexico and the southeastern Atlantic coast of the United States and much less commonly northward as far as Massachusetts. In Latin American Spanish, it is known as huachinango or pargo.

This species commonly inhabits waters from 30–200 ft (9.1–61.0 m), but can be caught as deep as 300 ft (91 m) on occasion. They stay relatively close to the bottom, and inhabit rocky bottoms, ledges, ridges, and artificial reefs, including offshore oil rigs and shipwrecks. Like most other snappers, northern red snapper are gregarious and form large schools around wrecks and reefs. These schools are usually made up of fish of very similar size.

The preferred habitat of this species changes as it grows and matures due to increased need for cover and changing food habits.[2][3] Newly hatched red snapper spread out over large areas of open benthic habitat, then move to low-relief habitats, such as oyster beds. As they near one year of age, they move to intermediate-relief habitats as the previous year’s fish move on to high-relief reefs with room for more individuals. Around artificial reefs such as oil platforms, smaller fish spend time in the upper part of the water column while more mature (and larger) adults live in deeper areas. These larger fish do not allow smaller individuals to share this territory. The largest red snapper spread out over open habitats, as well as reefs.

Reproduction and growth

Growth pattern with age of red snapper (equation from Diaz 2004)

Growth pattern with age of red snapper (equations from Szedlmayer et al., 1994)

Diaz[4] reported weight vs. length data for L. campechanus for the National Marine Fisheries Service (US). As northern red snapper grow longer, they increase in weight, but the relationship between length and weight is not linear. The relationship between total length (L, in inches) and total weight (W, in pounds) for nearly all species of fish can be expressed by an equation of the form:

W = cL^b\!\,

Invariably, b is close to 3.0 for all species, and c is a constant that varies among species.[5] Diaz reported that for red snapper, c=0.000010 and b=3.076. These values are for inputs of length in cm and result in weight in kg.

Szedlmayer et al. reported length vs. age data for L. campechanus in a primarily artificial reef environment off the coast of Alabama, USA: TL(age) = 1,025 (1 - e^( -0.15 age)), N=409, R = 0.96. For the first five years, growth can be estimated as being approximately linear: TL(age) = 97.7 age + 67.6, N = 397, R = 0.87 (for each equation, age is in years and total length is in mm).[6]

Removing a red snapper otolith (ear bone): Their age can be determined by counting annual growth rings on their otoliths, similar to counting growth rings in trees.

Northern red snappers move to different types of habitats during their growth process.[2] When they are newly spawned, red snapper settle over large areas of open benthic habitat(s). Below age 1, the red snapper move to low-relief habitats for food and cover. If available, oyster shell beds are preferred.[7] The second stage is when these fish outgrow low-relief habitats and move to intermediate-relief habitats as age 1 snapper leave to move on to another growth stage. Next, at about age 2, snapper seek high-relief reefs having low densities of larger snapper. Next, at platforms, smaller snapper occupy the upper water column. Then, the larger, older snapper occupy the deeper areas of the platforms and large benthic reefs and they prevent smaller snapper and other fish from using these habitats. In spite of local habitat preferences, Szedlmayer reported[6] that of 146 L. campechanus tagged, released and recaptured within about a year, 57% were still approximately at their respective release site, and 76% were recaptured within 2 km of their release site. The greatest movement by a single fish was 32 km.

A northern red snapper attains sexual maturity at two to five years old, and an adult snapper can live for more than 50 years. Research from 1999-2001 suggested the populations of red snapper off the coast of Texas reach maturity faster and at a smaller size than populations off of the Louisiana and Alabama coasts.[8]

Commercial and recreational use

Global capture of wild northern red snapper in tonnes, 1950–2010, as reported by the FAO [9]

Northern red snapper are a prized food fish, caught commercially, as well as recreationally. Red snapper is the most commonly caught snapper in the continental USA (almost 50% of the total catch), with similar species being more common elsewhere. They eat almost anything, but prefer small fish and crustaceans. They can be caught on both live and cut bait, and also take artificial lures, but with less vigor. They are commonly caught up to 10 lb (4.5 kg) and 20 in (510 mm) in length, but fish over 40 lb (18 kg) have been taken.

Red Snapper farming

Recreational fishing for northern red snapper has been popular for a long time, restricted mostly by fishing limits intended to ensure a sustainable population. The first minimum size limit was introduced in 1984, after a 1981 report described quickly declining harvests (both commercial and recreational)[10] From 1985 to 1990, the annual recreational catch of red snapper was about 1.5 million. From 1991 to 2005, the catch was substantially higher, varying from year to year from 2.5 to 4.0 million.[11]

When northern red snapper bite on a line, they tend to be nibblers and pickers, and a soft touch is needed when trying to catch them.[12] Because the older red snapper like structure, anglers use bottom fishing over reefs, wrecks, and oil rigs, and use line and supplies in the 50-lb class. Since the anglers have to both choose the right bait and present it correctly, they tend to use multiple hooked baits. Favorite baits include squid, whole medium-sized fish, and small strips of fish such as amberjack. Although many northern red snapper are caught on the bottom, in some situations the larger fish are caught on heavy jigs (artificial lures), often tipped with a strip of bait or by freelining baits at the proper upper level.[13]

Interest in recreational fishing for northern red snapper, and in the Gulf of Mexico in general, has increased dramatically. From 1995-2003, the number of Louisiana fishing charter guide license holders increased eight-fold.[10]

Since 1990, the total catch limit for northern red snapper has been divided into 49% for recreational fishermen and 51% for commercial. Commercially, they are caught on multiple-hook gear with electric reels. Fishing for red snapper has been a major industry in the Gulf of Mexico, but permit restrictions and changes in the quota system for commercial snapper fishermen in the Gulf have made the fish less commercially available.[14] Researchers estimate the bycatch of young red snapper, especially by shrimp trawlers, is a significant concern.

Genetic studies have shown many fish sold as red snapper in the USA are not actually L. campechanus, but other species in the family.[15][16] Substitution of other species for red snapper is more common in large chain restaurants which serve a common menu nationwide. In these cases, suppliers provide a less costly substitute (usually imported) for red snapper. In countries such as India, where the actual red snapper is not available in its oceans, John snapper, Russell snapper, or a tomato red snapper are sold as "red snapper".[15][16]

Fisherman with a northern red snapper catch

Snack of red snapper

Stocking in artificial reefs

Juvenile northern red snappers have been released on artificial reef habitats off the coast of Sarasota, Florida, to conduct investigations into the use of hatchery-reared juveniles to supplement native populations in the Gulf of Mexico.[17] Artificial reefs off the coast of Alabama have proven to be a favorite habitat of red snapper two years old and older. Gallaway et al.(2009) analyzed several studies and concluded, in 1992, 70 - 80% of the age two red snapper in that area were living around offshore oil platforms.[18]

Other species mistaken for red snapper

Sebastes, rockfish, are called red snapper or Pacific red snapper.

Several species of bigeye (Priacanthidae)

Spanish

El pargo del Golfo o huachinango , Lutjanus campechanus , es una especie nativa de pargo al oeste del Océano Atlántico , incluyendo el Golfo de México , donde habita en ambientes asociados a los arrecifes . Esta especie es de importancia comercial y también es codiciado como peces. [ 1 ]

El cuerpo del pargo del Golfo es muy similar en su forma a otros pargos , como el pargo de manglar , la sama , pargo , pargo perro. Todas cuentan con un perfil inclinado, medianas y grandes escalas, una aleta dorsal espinosa y un cuerpo comprimido lateralmente . Huachinango del Norte tiene , dientes cortos y afilados como agujas , pero carecen de los dientes caninos superiores prominentes se encuentran en la carne de carnero , perro y pargos de manglar. Este pargo alcanza la madurez en una longitud de unos 39 cm ( 15 pulgadas) . La longitud adulta común es de 60 cm ( 24 pulgadas) , pero puede llegar a 100 cm ( 39 pulgadas) . El peso máximo publicado es 22.8 kg (50 libras ) , y la edad más antigua reportada es de 57 años. [ 1 ] La coloración del pargo del Golfo es de color rojo claro , con mayor intensidad del pigmento en la parte posterior . Cuenta con 10 espinas dorsales, 14 radios dorsales suaves, tres espinas anales y de ocho a 9 radios blandos anales. Los ejemplares juveniles (menos de 30 a 35 cm) también puede tener una mancha oscura en sus lados , por debajo de los rayos dorsales suaves anteriores, que se desvanece con la edad. [ 1 ]

Distribución

L. campechanus , desde el Golfo de México

El pargo del Golfo se encuentra en el Golfo de México y la costa atlántica del sudeste de los Estados Unidos y mucho menos frecuentemente hacia el norte en cuanto a Massachusetts. En el español de América , se le conoce como el huachinango o pargo .

Esta especie habita comúnmente aguas 30-200 pies ( 9,1 a 61,0 m) , pero se puede coger a una profundidad de 300 pies ( 91 m) en la ocasión. Se quedan relativamente cerca de la parte inferior , y habitan en los fondos rocosos , cornisas , crestas, y los arrecifes artificiales, incluidas las plataformas petrolíferas en alta mar y los naufragios . Como la mayoría de los pargos , pargo del Golfo son gregarios y forman grandes cardúmenes alrededor de naufragios y arrecifes. Estas escuelas generalmente están compuestas por peces de tamaño muy similar.

El hábitat preferido de esta especie cambia a medida que crece y madura , debido a una mayor necesidad de cobertura y el cambio de hábitos alimenticios. [ 2 ] [ 3 ] recién nacidas pargo rojo se extendió a lo largo de grandes áreas de hábitat bentónico abierto , luego pasar a los hábitats de bajo relieve , tales como los bancos de ostras . Mientras cerca de un año de edad , se trasladan a hábitats de alivio intermedio como mueven los peces del año anterior sobre los arrecifes de alto relieve con espacio para más personas . Alrededor de arrecifes artificiales, como las plataformas petrolíferas , los peces más pequeños pasan el tiempo en la parte superior de la columna de agua , mientras más maduros (y más grandes ), los adultos viven en áreas más profundas. Estos peces más grandes no permiten a los individuos más pequeños para compartir este territorio . El mayor pargo distribuidos en hábitats abiertos , así como los arrecifes .

La reproducción y el crecimiento

Patrón de crecimiento con la edad del pargo rojo (ecuación de Diaz 2004 )

Patrón de crecimiento con la edad del pargo rojo (ecuaciones de Szedlmayer et al. , 1994 )

Díaz [ 4 ] informó de peso frente a los datos de longitud de L. campechanus para el Servicio Nacional de Pesca ( EE.UU. ) . Como pargo del Golfo se hacen más largas , que aumentan de peso, pero la relación entre la longitud y el peso no es lineal . La relación entre la longitud total (L, en pulgadas) y peso total ( W , en libras) para casi todas las especies de peces se puede expresar mediante una ecuación de la forma:

W = cL ^ b \! \ ,

Invariablemente , b está cerca de 3.0 para todas las especies , y c es una constante que varía entre las especies. [ 5 ] Díaz informó que para el pargo rojo, c = 0.000010 y b = 3,076 . Estos valores son para las entradas de la longitud en cm y resultan en peso en kg .

Szedlmayer et al . informó longitud frente a los datos de edad para L. campechanus en un entorno principalmente arrecifes artificiales en la costa de Alabama, EE.UU. : TL (edad) = 1025 ( 1 - e ^ ( -0,15 edad ) ), N = 409 , R = 0,96. Durante los primeros cinco años, el crecimiento puede ser estimado como aproximadamente lineal : TL (edad) = 97,7 + 67,6 años , N = 397 , R = 0,87 ( para cada ecuación , la edad es en años y la longitud total es en mm) [ . 6 ]

Extracción de un otolito pargo rojo ( hueso del oído ) : La edad se puede determinar contando los anillos de crecimiento anuales en los otolitos , similar a contar los anillos de crecimiento de los árboles.

Pargos rojos del norte se mueven a diferentes tipos de hábitats durante su proceso de crecimiento. [ 2 ] Cuando están recién engendraron , pargos rojos se asientan en grandes áreas de hábitat bentónico abierto ( s ) . Por debajo de 1 años de edad, el pargo rojo desplazarse a hábitats de bajo relieve para la alimentación y la cubierta . Si están disponibles , se prefieren las capas de conchas de ostras. [ 7 ] La segunda etapa es cuando estos peces superan los hábitats de bajo relieve y desplacen a un hábitat de alivio intermedia como la edad 1 licencia pargo a pasar a otra etapa de crecimiento. A continuación, aproximadamente a los 2 años, pargo buscan arrecifes de alto relieve que tienen baja densidad de grandes pargos. A continuación, en plataformas , pargos pequeños ocupan toda la columna de agua superior . Entonces , los pargos más grandes y viejos ocupan las zonas más profundas de las plataformas y grandes arrecifes bentónicos y evitan más pequeño pargo y otros peces del uso de estos hábitats. A pesar de las preferencias locales de hábitat , Szedlmayer informó [ 6 ] la de 146 L. campechanus etiquetado , puesto en libertad y recapturado dentro de aproximadamente un año , el 57% todavía estaban aproximadamente en su respectiva área de liberación , y el 76% fue recapturado a menos de 2 km de su liberación sitio. El mayor movimiento de un solo pez fue de 32 km.

Un pargo del Golfo alcanza la madurez sexual a los dos a cinco años de edad, y un pargo adulto puede vivir por más de 50 años. La investigación de 1999-2001 sugirió a las poblaciones de pargo en las costas de Texas, alcanzan la madurez más rápido y con un tamaño más pequeño que las poblaciones fuera de las costas de Luisiana y Alabama . [ 8 ]

Uso comercial y recreativo

Mundial de captura de pargo del Golfo salvaje en toneladas, 1950-2010 , según ha informado la FAO [ 9 ]

Huachinango del Norte es un pescado muy apreciado alimento , atrapados en el comercio, así como de forma recreativa . Pargo rojo es el pargo capturado con mayor frecuencia en el territorio continental de EE.UU. (casi el 50 % de la captura total ), con especies similares son más comunes en otros lugares. Comen casi cualquier cosa , pero prefieren pequeños peces y crustáceos. Pueden quedar atrapadas en tanto vivir y cortan cebo, y también toman señuelos artificiales , pero con menos vigor . Ellos son comúnmente atrapados hasta 10 libras ( 4,5 kg) y 20 in ( 510 mm ) de longitud, pero los peces de más de 40 lb ( 18 kg) se han tomado .

La pesca recreativa de pargo del Golfo ha sido popular durante mucho tiempo , limitada en su mayoría por los límites de pesca destinadas a garantizar una población sostenible. El primer límite mínimo se introdujo en 1984, después de un informe de 1981 describió la disminución de las cosechas rápidamente ( tanto comercial como recreativa) [ 10 ] De 1985 a 1990, la deportiva anual de pargo rojo era alrededor de 1,5 millones de dólares. Entre 1991 y 2005 , la captura fue sustancialmente mayor , variando de un año a 2,5-4,0 millones de dólares. [ 11 ]

Cuando pargo del Golfo morder en una línea, que tienden a ser nibblers y recolectores , y se necesita un toque suave al intentar atraparlos. [ 12 ] Debido a que el pargo mayores como la estructura, los pescadores utilizan la pesca de fondo en los arrecifes , restos de naufragios y plataformas petroleras, y el uso de la línea y los suministros de la clase de 50 libras . Dado que los pescadores tienen que elegir tanto el cebo adecuado y presentarla correctamente , tienden a utilizar varios cebos en forma de gancho . Cebos preferidos incluyen calamares, pescado entero de tamaño medio y pequeñas tiras de peces como el jurel . Aunque muchos pargo del Golfo se encuentran atrapados en la parte inferior , en algunas situaciones los peces grandes son capturados en jigs pesados ( señuelos artificiales), a menudo inclinado con una tira de cebo o por freelining cebos en el nivel superior adecuado. [ 13 ]

El interés en la pesca recreativa de pargo del Golfo y en el Golfo de México , en general , ha aumentado de forma espectacular. Desde 1995-2003 , el número de Louisiana guía de charter de pesca los titulares de licencias se multiplicó por ocho . [ 10 ]

Desde 1990, el total de capturas de pargo del Golfo se ha dividido en 49 % para los pescadores deportivos y el 51% para comercial. Comercialmente, se ven atrapados en el engranaje de múltiples gancho con carretes eléctricos . La pesca de pargo rojo ha sido una industria importante en el Golfo de México , pero las restricciones de permisos y los cambios en el sistema de cuotas para los pescadores comerciales de pargo del Golfo han hecho que el pescado menos disponible en el mercado . [ 14 ] Los investigadores estiman que la captura incidental de pargo rojo joven , sobre todo por los arrastreros de camarón , es una preocupación significativa .

Los estudios genéticos han demostrado que muchos peces se venden como el pargo rojo en los EE.UU. no son en realidad L. campechanus , pero otras especies de la familia . [ 15 ] [ 16 ] La sustitución de otras especies de pargo rojo es más común en las grandes cadenas de restaurantes que sirven una menú común en todo el país . En estos casos , los proveedores ofrecen un sustituto menos costoso (generalmente importado) para el pargo rojo. En países como la India, donde el pargo rojo real no está disponible en sus océanos , John pargo , pargo Russell , o un pargo rojo tomate se venden como " pargo " . [ 15 ] [ 16 ]

Stocking en arrecifes artificiales

Pargos rojos juvenil del norte han sido puestos en libertad en los hábitats de arrecifes artificiales en la costa de Sarasota , Florida, para llevar a cabo investigaciones sobre el uso de los juveniles criados en vivero para reforzar las poblaciones nativas en el Golfo de México . [17] Los arrecifes artificiales en la costa de Alabama han demostrado ser un hábitat favorito de pargo dos años de edad y mayores. . Gallaway et al (2009 ) analiza varios estudios y llegó a la conclusión , en 1992 , el 70 - 80% de la edad de dos pargo rojo en esa zona vivían alrededor de las plataformas petrolíferas en alta mar [ 18 ] .

Otras especies confundidas con pargo rojo

Sebastes , pescado de roca , se llaman pargo o huachinango .

Varias especies de patudo ( Priacanthidae )

Notes/Referencias

1. Froese, Rainer and Pauly, Daniel, eds. (2013). "Lutjanus campechanus" in FishBase. December 2013 version.

2. Gallaway, BJ, Szedlmayer, ST, Gazey, WJ. A life history review for red snapper in the Gulf of Mexico with an evaluation of the importance of offshore petroleum platforms and other artificial reefs. Reviews in Fisheries Science 17(1):48-67, 2009.

3. Szedlmayer, ST. An evaluation of the benefits of artificial habitats for red snapper, Lutjanus campechanus, in northeast Gulf of Mexico. Proceedings of the Gulf and Caribbean Fisheries Institute, 2007

4. Diaz, GA. Allometric relationships of Gulf of Mexico red snapper. National Marine Fisheries Service publication SEDAR7-AW-02, August, 2004

5. R. O. Anderson and R. M. Neumann, Length, Weight, and Associated Structural Indices, in Fisheries Techniques, second edition, B.E. Murphy and D.W. Willis, eds., American Fisheries Society, 1996.

6. Szedlmayer, S.T. and R.L. Shipp. 1994. Movement and growth of red snapper, Lutjanus campechanus, from an artificial reef area in the northeast Gulf of Mexico. Bulletin of Marine Science 55:887-895.

7. Szedlmayer ST and Howe JC. Substrate preference in age-0 red snapper, Lutjanus campechanus. Environmental Biology of Fishes 50:203-207, 1997

8. Fischer 2004

9. Based on data sourced from the FishStat database

10. LSU Fisheries Page on Red Snapper management accessed 5 July 2011.

11. Scott GP. Estimates of historical red snapper recreational catch levels using US Census Data and Recreational Survey Information. National Marine Fisheries Service, August 2004, SEDAR7-AW16

12. Red Snapper information on TakeMeFishing.org

13. Schultz K. Essentials of Fishing: The only guide you need to catch freshwater and saltwater fish. John Wiley & Sons, Inc. 2010, p. 90

14. Hoyt Childers. "IFQ's first year raises ex-vessel prices, but quota cut leaves room for imports". National Fisherman. Retrieved July 31, 2008.

15. E. Weise (July 14, 2004). "Bait and switch: study finds red snapper mislabeled". USA Today. Retrieved June 18, 2008.

16. J. R. Fuller (May 10, 2007). "Fish fraud: The menus said snapper, but it wasn't!". Chicago Sun Times. Retrieved June 18, 2008.

17. Brett Ramey Blackburn, Nathan Brennan & Ken Leber (2003). In situ scuba diver identification of hatchery released red snapper, Lutjanus campechanus, using visual implant elastomer tags in the Gulf of Mexico. In S. F. Norton. "Diving for Science...2003". Proceedings of the American Academy of Underwater Sciences (22nd annual Scientific Diving Symposium): 19.

18. Gallaway, B.J. Szedlmayer, S.T. Gazey W.J. Reviews in Fisheries Science 17(1):48-67, 2009

Tuna

The blue fin tuna is the most prized of 1he tuna family.

A large fish grows to 3 m in length and 500 kg in weight as an adult. As the result of its good taste and high price, it has been overfish in recent years, resulting in the decrease in numbers.

As a countermeasure, action has been taking worldwide to reduce catches. Today, a large quantity of the marketed blue fin tuna is farm-raised, which comes from wild-caught seed that have been raise to marketable size.

If the fry are overfished, it is foresee that farm-raised numbers will also decline.

To maintain supplies under such severe conditions, technology for completely farm-raising blue fin tuna is need. The technology Involves raising artificially hatched larvae to adults, collecting eggs from them and artificially hatching those eggs to create the next generation. The fish are farm-raised in all stages without requiring wild stock.

Farm raised adults

The fish become adults after five years of cultivation.

They grow to 2 m in length and 200 kg in weight

Fertilized eggs

The Fertilized eggs float to the surface where they are spawning. Being just 1 mm in diameter,

it is estimate that several million eggs are collect from a single mother.

Fry

About 20 days after hatching, the larvae grow into fry.

At this time, the fry moved from land-based tanks to nets in the sea.

Younglings

Roughly, 3 months from hatching, the fish are about 30 cm in length and weigh about 300 g.

Adults

In about 3 years, the fish become adults more than 1 m in length and 30 kg in weight. They are ship at this size.

Octopus

The development of octopus aquaculture, the farming of octopus, is being driven by strong market demands in the Mediterranean and in South American and Asian countries.[1] Octopus live short lives, growing rapidly and maturing early. They typically reach two or three kilograms (high weights for invertebrates). There is little overlap between successive generations.[2]

The supply of octopus has been constrained by overfishing in many key fisheries.[3] The common octopus seems particularly suitable for aquaculture. However, it is currently difficult to culture the early life stages of octopus and maintain high survival rates for their paralarvae. This difficulty is limiting the development of fully closed life cycle octopus hatchery systems.

Contents

1 Species

2 Temperature

3 Nutrition

4 Juveniles

5 Paralarva

6 Notes

7 External links

Species

Graph showing the decline in the global capture production (in tonnes) of the common octopus over recent years (source FAO[4])

The aquaculture potential of several octopus species has been investigated in recent years, including Octopus maya,[5] Octopus bimaculoides,[6] Octopus ocellatus,[7] and Octopus mimus.[8]

The common octopus, Octopus vulgaris, appears to be the most serious candidate for aquaculture in terms of its biological and market potential.[9] It has a worldwide distribution in tropical, subtropical and temperate waters. It is a benthic species occurring from the coastal line to the outer edge of the continental shelf, at depths of up to 200 m and in very diverse marine habitats.[10] The common octopus is easily adapted to captive conditions and has a rapid growth rate of 5% body weight per day.[9] It also has a high feed conversion rate with 30–60% of ingested food being incorporated in its own weight,[11][12] and a high fecundity of 100,000–500,000 eggs per female.[11]

Temperature

There is an optimum temperature at which a cold-blooded species does best in terms of growth, survival and food intake. The common octopus is sensitive to temperature, with an optimum range for commercial growth of 16–21 °C.[12] Above its optimal thermal range, growth and food intake decrease, and above 23 °C loss in weight and increased mortality has been recorded.[12] A narrow thermal band can mean seasonality in growth due to seasonal variations in water temperatures. The incorporation of temperature control mechanisms, such as in the use of closed or onshore farming systems, can reduce seasonal variances in production.[12]

Nutrition

Crustaceans, such as crabs and lobster are an important dietary constituent of both natural and captive populations of octopus.[13] Fish are not as important. Fish-based diets have been shown to provide both lower growth rates and food conversion to growth ratios in captive octopus. This may be because of high lipid levels in fish flesh.[12] Cephalopods, such as octopus and squids, show low lipid digestibility as a result of low lipid requirements. Consequently a large component of the fish feed will not be taken up.[14] Crustacean diets are favored possibly as a result of their high protein relative to lipid levels.[12]

Whether octopus farming is profitable depends in large part on how much it costs to maintain a steady supply of crustaceans.[13] Economic profitability can be maximized without significantly compromising biological productivity by incorporating a mix of fish and crustacean-based feed strategies. García García and Cerezo Velverde (2006) found a feeding regime of one day of crab followed by three days of fish can reduce the cost of producing one kg of octopus by a predicted value of €2.96.[13]

Juveniles

Commercial aquaculture so far has been confined to starting with young juveniles caught in the wild, weighing about 750 g. In Spain, these juveniles are purchased from local fishermen and transferred to offshore floating sea cages. There they are fattened with bycatch (fish, molluscs and crabs) for several months until a commercial size, about 3 kilograms, is reached. However, acquiring juveniles in this way, from the wild, further increases the fishing pressure on octopus stocks that are already managed badly, possibly producing cascades in marine ecosystems. A cost analysis of this practice found that over 40% of total costs went into acquiring the juveniles. The profitability of this approach is low, depending as it does on fishing and the supply of sub-adults, a costly and highly variable process.[15]

Paralarva

The bottleneck currently hindering the commercial development of octopus aquaculture is the difficulty of rearing octopus during their early paralarva stage.[16][17] Paralarva is the name given to the larva of cephalopods. Paralarvae are small, less than 3 millimetres at hatching, with a long planktonic life stage. Current rearing techniques are inadequate, resulting in very high mortality rates.[18] Results vary when octopus paralarvae are fed different combinations of prey. The best results have been with a mix of brine shrimp and other living prey, such as crab zoeae.[1][16] However the survival and settlement rates of the paralarvae is typically low in such studies, highlighting the difficulties in raising octopus paralarvae. Maintaining high survival rates for paralarvae appears to be the main factor limiting the development of a fully closed life cycle octopus hatchery system.[19]

To achieve both profitable and environmentally sustainable results, much research has been focused on paralarval rearing.[17] In 2005, scientists from the principal research groups in the field concluded the key factor affecting paralarval mortality is nutrition, making nutritional research the highest priority.[19] There is "no reason not to believe that the aquacultural rearing of octopus will be of great economic potential" as soon as the rearing technology and nutritional issues have been addressed.[15] Research in these areas is promising.[15]

Notes

1. Iglesias, J., Otero, J.J., Moxica, C., Fuentes, L., Sánchez, F.J. (2004) "The completed life cycle of the octopus (Octopus vulgaris, Cuvier) under culture conditions: paralarval rearing using Artemia and zoeae, and first data on juvenile growth up to 8 months of age" Aquac. Int. 12: 481–487.

2. Boyle, P.R., Rodhouse, P.G. (2005) Cephalopods: ecology and fisheries Wiley-Blackwell. ISBN 978-0-632-06048-1.

3. FAO (2010) The State of the World Fisheries and Aquaculture 2010. FAO, Rome. Page 41.

4. Octopus vulgaris FAO: Species Fact Sheets, Rome.

5. Rosas, C., Cuzon, G., Pascual, C., Gaxiola, G., Chay, Lòpez, N., Maldonado, T., Domingues, P.M. (2007) "Energy balance of Octopus maya fed crab or an artificial diet" Marine Biology, 152: 371–381.

6. Solorzano, Y., Viana, M.T., López, L.Mc, Correa, J.G.,True, C.C., Rosas, C. (2009) "Response of newly hatched Octopus bimaculoides fed enriched Artemia salina: Growth performance, ontogeny of the digestive enzyme and tissue amino acid content" Aquaculture, 289: 84–90.

7. Segawa, S., Nomoto, A. (2002) "Laboratory growth, feeding, oxygen consumption and ammonia excretion of Octopus ocellatus" Bulletin of Marine Science, 71: 801–813.

8. Baltazar, P., Rodríguez, P., Rivera, W., Valdivieso, V. (2000) "Cultivo experimental de Octopus mimus, Gould 1852 en perú" Revista Peruana de Biología, 7: 151–160.

9. Iglesias J., Sánchez F.J. and Otero J.J. (1997) "Primeras experiencias sobre el cultivo integral del pulpo (Octopus vulgaris, Cuvier) en el Instituto Español de Oceanografía". In: Costa J., Abellán E., García García B., Ortega A. and Zamora S. (Eds.), VI Congreso Nacional de Acuicultura, Cartagena, Spain, pp. 221–226.

10. Guerra, A. (1992) "Mollusca: Cephalopoda" In: Ramos, M.A., et al. (Eds.) Fauna Iberica, vol. 1. Museo Nacional de Ciencias Naturales, CSIC, Madrid, p. 327. ISSN:84-00-07010-0.

11. Mangold, K.M. (1983) "Octopus vulgaris". In: Boyle, P.R. (Ed.), Cephalopod Life Cycles, vol. 1. Academic Press, London, pp. 335–364.

12. Aguado, F., García García, B. (2002) "Growth and food intake models in Octopus vulgaris Cuvier/1797: influence of body weight, temperature, sex and diet" Aquac. Int. 10: 361–377.

13. García García, B., Cerezo Valverde, J. (2006) "Optimal proportions of crabs and fish in diet for common octopus (Octopus vulgaris) ongrowing" Aquaculture, 253: 502–511.

14. Lee P.G. (1994) "Nutrition of cephalopods: Fueling the system" In: Pörtner H.O., O’Dor R.K. and Mac- millan D.L. (eds), Physiology of Cephalopod Molluscs: Lifestyle and Performance Adaptations Gordon & Brench Publishers, Switzerland, pp. 35–51.

15. García García, J., Rodriguez Gonzalez, L.M., García García, B. (2004) "Cost analysis of octopus ongrowing installation in Galicia" Span. Jour. Agr. Res. 2(4): 521-537.

16. Carrasco, J.F., Arronte, J.C., Rodríguez, C. (2006) "Paralarval rearing of the common octopus, Octopus vulgaris (Cuvier)" Aquac. Res. 37: 1601–1605.

17. Vaz-Pires, P., Seixas, P., Barbosa, A. (2004) "Aquaculture potential of the common octopus (Octopus vulgaris Cuvier, 1797): a review" Aquaculture, 238(1–4): 221–238.

18. Moxica, C; F. Linares, J. J. Otero, J. Iglesias and F. J. Sánchez(2002) "Cultivo intensivo de paralarvas de pulpo, Octopus vulgaris Cuvier, 1797, en tanques de 9 m3" Bol. Inst. Esp. Oceanogr., 18 (1-4): 31-36.

19. Iglesiasa J.; F.J. Sáncheza, J.G.F. Bersanob, J.F. Carrascoc, J. Dhontd, L. Fuentesa, F. Linarese, J.L. Muñozf, S. Okumurag, J. Rooh, T. van der Meereni, E.A.G. Vidalj and R. Villanuevak (2007) "Rearing of Octopus vulgaris paralarvae: Present status, bottlenecks and trends" Aquaculture, 266 (1-4): 1–15.

External links

20. Jiménez, Lourdes; Virgilio Arenas, Daniel Méndez, Gerardo Preciado, Ana Gabriela Díaz and Mitzy Blanco (2009) Sustainable Octopus Fishery Program in Veracruz Reef System National Park, Mexico World Aquaculture Society, , World Aquaculture 2009. Conference presentation

21. Seixas, Pedro F. and Manuel Rey-Méndez (2006) Potential use of octopus species for aquaculture: Present state of the situation, perspectives and limitations World Aquaculture Society, AQUA 2006, Firenze, Italy. Conference presentation

Salmonid aquaculture

The aquaculture of salmonids is the farming and harvesting of salmonids under controlled conditions. Salmonids (particularly salmon and steelhead), along with carp, are the two most important fish groups in aquaculture.[1] The most commonly farmed salmonid is the Atlantic salmon. Other commonly farmed fish groups include tilapia, catfish, sea bass and bream.

In 2007 the aquaculture of salmonids was worth US$10.7 billion. Salmonid aquaculture production grew over ten-fold during the 25 years from 1982 to 2007. Leading producers of farmed salmonids are Norway with 33 percent, Chile with 31 percent, and other European producers with 19 percent.[2]

There is currently much controversy about the ecological and health impacts of intensive salmonids aquaculture. There are particular concerns about the impacts on wild salmon and other marine life. Some of this controversy is part of a major commercial competitive fight for market share and price between Alaska commercial salmonid fishermen and the rapidly evolving salmonid aquaculture industry.[3]

Aquaculture production of salmons in tons 1950-2010 as reported by FAO

Contents

1 Methods

1.1 Hatcheries

1.2 Sea cages

1.3 Feeding

1.4 Harvesting

2 Wild versus farmed

3 Issues

3.1 Disease and parasites

3.2 Pollution and contaminants

3.3 Impact on wild salmonids

3.4 Genetic modification

3.5 Impact on forage fish

3.6 Salmon Aquaculture Dialogue

4 Hatch and release

5 Species

5.1 Atlantic salmon

5.2 Steelhead

5.3 Coho salmon

5.4 Chinook salmon

6 Timeline

7 Notes

8 References

9 Further reading

10 External links

Salomon farm in Finland

Methods

Assynt Salmon hatchery, near Inchnadamph in the Scottish Highlands.

A salmon farm which holds yearlings for up to two years. Many hold broodstock for even longer in these conditions to help ensure large, sexually mature adults.

Very young fertilised salmon eggs; notice the developing eyes and vertebral column.

Salmon egg hatching. In about 24hrs it will be a fry without the yolk sac.

The aquaculture or farming of salmonids can be contrasted with capturing wild salmonids using commercial fishing techniques. However, the concept of "wild" salmon as used by the Alaska Seafood Marketing Institute includes stock enhancement fish produced in hatcheries that have historically been considered ocean ranching. The percentage of the Alaska salmon harvest resulting from ocean ranching depends upon the species of salmon and location,[4] however it is all marketed as "wild Alaska salmon".

Methods of salmonid aquaculture originated in late 18th century fertilization trials in Europe. In the late 19th century, salmon hatcheries were used in Europe and North America. From the late 1950s, enhancement programs based on hatcheries were established in the United States, Canada, Japan and the USSR. The contemporary technique using floating sea cages originated in Norway in the late 1960s.[5]

Salmonids are usually farmed in 2 stages and in some places maybe more. First, the salmon are hatched from eggs and raised on land in freshwater tanks. When they are 12 to 18 months old, the smolt (juvenile salmon) are transferred to floating sea cages or net pens anchored in sheltered bays or fjords along a coast. This farming in a marine environment is known as mariculture. There they are fed pelleted feed for another 12 to 24 months, when they are harvested.[6]

Norway produces 33 percent of the world's farmed salmonids, and Chile produces 31 percent.[2] The coastlines of these countries have suitable water temperatures and many areas well protected from storms. Chile is close to large forage fisheries which supply fish meal for salmon aquaculture. Scotland and Canada are also significant producers.[7]

Modern salmonid farming systems are intensive. Their ownership is often under the control of huge agribusiness corporations, operating mechanised assembly lines on an industrial scale. In 2003, nearly half of the world’s farmed salmon was produced by just five companies.[8]

Hatcheries

Modern commercial hatcheries for supplying salmon smolts to aquaculture net pens have been shifting to Recirculating Aquaculture Systems (RAS) where the water is recycled within the hatchery. This allows location of the hatchery to be independent of a significant fresh water supply and allows economical temperature control to both speed up and slow down the growth rate to match the needs of the net pens.

Conventional hatchery systems operate flow through where spring water or other water source flow into the hatchery. The eggs are then hatched in trays and the salmon smolts produced in raceways. The waste products from the growing salmon fry and the feed are usually discharged into the local river. Conventional flow through hatcheries, such as are being used by most of the Alaska ocean ranching enhancement hatcheries use more than 100 tons of water to produce a kg of smolts.

An alternative method to hatching in freshwater tanks is to use spawning channels. These are artificial streams, usually parallel to an existing stream with concrete or rip-rap sides and gravel bottoms. Water from the adjacent stream is piped into the top of the channel, sometimes via a header pond to settle out sediment. Spawning success is often much better in channels than in adjacent streams due to the control of floods which in some years can wash out the natural redds (pronounced same as the color 'red') . Because of the lack of floods, spawning channels must sometimes be cleaned out to remove accumulated sediment. The same floods which destroy natural redds also clean them out. Spawning channels preserve the natural selection of natural streams as there is no temptation, as in hatcheries, to use prophylactic chemicals to control diseases. However, exposing fish to wild parasites and pathogens using uncontrolled water supplies, combined with the high cost of spawning channels, makes this technology unsuitable for salmon aquaculture businesses. This type of technology is only useful for stock enhancement programs.

Sea cages

Sea cages, also called sea pens or net pens, are usually made of mesh framed with steel or plastic. They can be square or circular, 10 to 32 metres across and 10 metres deep, with volumes between 1,000 and 10,000 cubic metres. A large sea cage can house up to 90,000 fish.

They are usually placed side by side to form a system called a seafarm or seasite, with a floating wharf and walkways along the net boundaries. Additional nets can also surround the seafarm to keep out predatory marine mammals. Stocking densities range from 8 to 18 kilograms per cubic metre for Atlantic salmon and 5 to 10 kilograms per cubic metre for Chinook salmon.[6][9]

In contrast to closed or recirculating systems, the open net cages of salmonid farming lower production costs, but provide no effective barrier to the discharge of wastes, parasites and disease into the surrounding coastal waters.[8] Farmed salmon in open net cages can escape into wild habitats, for example, during storms.

An emerging wave in aquaculture is applying the same farming methods used for salmonids to other carnivorous finfish species, such as cod, bluefin tuna, halibut and snapper. However, this is likely to have the same environmental drawbacks as salmon farming.[8][10]

See also: Copper alloys in aquaculture

A second emerging wave in aquaculture is the development of copper alloys as netting materials. Copper alloys have become important netting materials because they are antimicrobial (i.e., they destroy bacteria, viruses, fungi, algae, and other microbes) and they therefore prevent biofouling (i.e., the undesirable accumulation, adhesion, and growth of microorganisms, plants, algae, tubeworms, barnacles, mollusks, and other organisms). By inhibiting microbial growth, copper alloy aquaculture cages avoid costly net changes that are necessary with other materials. The resistance of organism growth on copper alloy nets also provides a cleaner and healthier environment for farmed fish to grow and thrive.

Feeding

Salmonids are carnivorous and are currently being fed compound fish feeds containing fish meal and other feed ingredients, ranging from wheat byproducts to soybean meal and feather meal. Being aquatic carnivores, salmonids don't tolerate or properly metabolize many plant based carbohydrates and use fats instead of carbohydrates as a primary energy source. With the amount of world wide fish meal production being almost a constant amount for the last 30+ years and at maximum sustainable yield (MSY), much of the fish meal market has shifted from chicken and pig feed to fish and shrimp feeds as aquaculture has grown in this time period.[11] Work continues on substituting vegetable proteins and protein concentrates for fish meal in the salmonid diet. Many substitutions for fish meal are known and diets containing zero fish meal are possible. For example a planned closed containment salmon fish farm in Scotland uses ragworms, algae and amino acids as feed.[12] However, commercial economic animal diets are determined by least cost linear programming models that are effectively competing with similar models for chicken and pig feeds for the same feed ingredients and these models show that fish meal is more useful in aquatic diets than in chicken diets, where they can make the chickens taste like fish.[13] Unfortunately, this substitution can result in lower levels of the highly valued omega-3 content in the farmed product. However, when vegetable oil is used in the growing diet as an energy source and a different finishing diet containing high omega-3 content fatty acids from either fish oil, algae oils or some vegetable oils are used a few months before harvest, this problem is eliminated.[14] At the present time, more than 50 percent of the world fish oil production is feed to farmed salmonids.[15] Farm raised salmonids are also fed the carotenoids astaxanthin and canthaxanthin, so that their flesh colour matches wild salmon, which also contain the same carotenoid pigments from their diet in the wild.[16] On a dry-dry basis, it takes 2–4 kg of wild caught fish to produce one kg of salmon.[17] Wild salmon require about 10 kg of forage fish to produce a kg of salmon, as part of the normal trophic level energy transfer. The difference between the two numbers is related to farmed salmon feed containing other ingredients beyond fish meal and the fact that farmed fish don't spend a lot of metabolic energy catching a dinner that doesn't want to be caught.

Harvesting

Modern harvesting methods are shifting towards using wet well ships to transport live salmon to the processing plant. This allows the fish to be killed, bled, and filleted before rigour has occurred. This results in superior product quality to the customer along with more humane processing. To obtain maximum quality, it is necessary to minimize the level of stress in the live salmon until actually being electrically and percussively killed and the gills slit for bleeding.[18] These improvements in processing time and freshness to the final customer are commercially significant and forcing the commercial wild fisheries to upgrade their processing to the benefit of all seafood consumers.

An older method of harvesting is to use a sweep net, which operates a bit like a purse seine net. The sweep net is a big net with weights along the bottom edge. It is stretched across the pen with the bottom edge extending to the bottom of the pen. Lines attached to the bottom corners are raised, herding some fish into the purse, where they are netted. Before killing, the fish are usually rendered unconscious in water saturated in carbon dioxide, although this practice is being phased out in some countries due to ethical and product quality concerns. More advanced systems use a percussive-stun harvest system that kills the fish instantly and humanely with a blow to the head from a pneumatic piston. They are then bled by cutting the gill arches and immediately immersing them in iced water. Harvesting and killing methods are designed to minimise scale loss, and avoid the fish releasing stress hormones, which negatively affect flesh quality.[9]

Wild versus farmed

Wild salmonids are captured from wild habitats using commercial fishing techniques. Most wild salmonids are caught in North American, Japanese and Russian fisheries. The following table shows the changes in production of wild salmonids and farmed salmonids over a period of 25 years, as reported by the FAO.[19] Russia, Japan and Alaska all operate major hatchery based stock enhancement programs that are really ocean ranching. The resulting fish hatchery fish are defined as "wild" for FAO and marketing purposes.

Salmonid production in tonnes by species

1982 2007

Species Wild Farmed Wild Farmed

Atlantic salmon 10,326 13,265 2,989 1,433,708

Steelhead 171,946 604,695

Coho salmon 42,281 2,921 17,200 115,376

Chinook salmon 25,147 8,906 11,542

Pink salmon 170,373 495,986

Chum salmon 182,561 303,205

Sockeye salmon 128,176 164,222

Total salmonid production

1982 2007

tonnes percent tonnes percent

Wild 558,864 75 992,508 31

Farmed 188,132 25 2,165,321 69

Overall 746,996 3,157,831

Issues

There is currently much controversy about the ecological and health impacts of intensive salmonid aquaculture. There are particular concerns about the impacts on wild salmonids and other marine life and on the incomes of commercial salmonid fishermen. [3]

Salmon farming controversy

Disease and parasites

Diseases and parasites in salmon

In 1972, Gyrodactylus, a monogenean parasite, was introduced with live trout and salmon from Sweden (baltic stocks are immune to Gyrodactylus) into government operated hatcheries. From the hatcheries, infected eggs, smolt and fry was implanted in many rivers with the goal to strengthen the wild salmon stocks, but caused instead devastation to some of the wild salmon populations affected.[20]

ISA virus

In 1984, infectious salmon anemia (ISAv) was discovered in Norway in an Atlantic salmon hatchery. Eighty percent of the fish in the outbreak died. ISAv, a viral disease, is now a major threat to the viability of Atlantic salmon farming. It is now the first of the diseases classified on List One of the European Commission’s fish health regime. Amongst other measures, this requires the total eradication of the entire fish stock should an outbreak of the disease be confirmed on any farm. ISAv seriously affects salmon farms in Chile, Norway, Scotland and Canada, causing major economic losses to infected farms.[21] As the name implies, it causes severe anemia of infected fish. Unlike mammals, the red blood cells of fish have DNA, and can become infected with viruses. The fish develop pale gills, and may swim close to the water surface, gulping for air. However, the disease can also develop without the fish showing any external signs of illness, the fish maintain a normal appetite, and then they suddenly die. The disease can progress slowly throughout an infected farm and, in the worst cases, death rates may approach 100 percent. It is also a threat to the dwindling stocks of wild salmon. Management strategies include developing a vaccine and improving genetic resistance to the disease.[22]

In the wild, diseases and parasites are normally at low levels, and kept in check by natural predation on weakened individuals. In crowded net pens they can become epidemics. Diseases and parasites also transfer from farmed to wild salmon populations. A recent study in British Columbia links the spread of parasitic sea lice from river salmon farms to wild pink salmon in the same river.[8] The European Commission (2002) concluded "The reduction of wild salmonid abundance is also linked to other factors but there is more and more scientific evidence establishing a direct link between the number of lice-infested wild fish and the presence of cages in the same estuary."[23] It is reported that wild salmon on the west coast of Canada are being driven to extinction by sea lice from nearby salmon farms.[24] These predictions have been disputed by other scientists[25] and recent harvests have indicated that the predictions were in error.

Pollution and contaminants

Salmonid farms are typically sited in marine ecosystems with good water quality, high water exchange rates, current speeds fast enough to prevent pollution of the bottom but slow enough to prevent pen damage, protection from major storms, reasonable water depth and a reasonable distance from major infrastructure such as ports, processing plants and logistical facilities like airports. Logistical considerations are significant and feed and maintenance labor must be transported to the facility and the product returned. Siting decisions are complicated by complex politically driven permitting problems in many countries that prevents optimal locations for the farms.

In sites without adequate currents there can be an accumulation of heavy metals on the benthos (sea floor ecological community) near the salmon farms, particularly copper and zinc.[9]

Contaminants are also found in the flesh of farmed salmon.[26] A 2004 study, reported in Science, analysed farmed and wild salmon for organochlorine contaminants. They found the contaminants were higher in farmed salmon. Within the farmed salmon, European (particularly Scottish) salmon had the highest levels, and Chilean salmon the lowest.[27] A follow up study confirmed this, and found levels of dioxins, chlorinated pesticides, PCBs and other contaminants up to ten times greater in farmed salmon than wild Pacific salmon.[28] On a positive note, further research using the same fish samples used in the previous study, showed that farmed salmon contained levels of beneficial fatty acids that were two to three times higher than wild salmon.[29] A follow up benefit-risk analysis on salmon consumption balanced the cancer risks with the (n-3) fatty acid advantages of salmon consumption. They found that recommended levels of (n-3) fatty acid consumption can be achieved eating farmed salmon with acceptable carcinogenic risks, but recommended levels of EPA+DHA intake cannot be achieved solely from farmed (or wild) salmon without unacceptable carcinogenic risks.[30] The conclusions were that

"...consumers should not eat farmed fish from Scotland, Norway and eastern Canada more than three times a year; farmed fish from Maine, western Canada and Washington state no more than three to six times a year; and farmed fish from Chile no more than about six times a year. Wild chum salmon can be consumed safely as often as once a week, pink salmon, Sockeye and Coho about twice a month and Chinook just under once a month."[26]

Health Canada currently believes that there is no need for specific advice regarding fish consumption vis-à-vis PCB exposure. [31]

Current Canadian dietary guidelines state Eat at least two Food Guide Servings of fish each week. Choose fish such as char, herring, mackerel, salmon, sardines and trout. [32]

The USA in their Dietary guidelines for 2010 recommends eating 8 ounces per week of a variety of seafood and 12 ounces for lactating mothers. No upper limits set and no restrictions on eating farmed or wild salmon. [33]

In an "Update of the monitoring of levels of dioxins and PCBs in food and feed" to the European Food Safety Authority in July 2012 stated unequivocally

"Farmed salmon and trout contained on average less dioxins and PCBs than wild-caught salmon and trout."

[34] This quote is from the European Food information Council ( EUFIC) in reaction to the 2004 paper "Global Assessment of Organic Contaminants in Farmed Salmon"

"Public concerns were raised earlier this year following the publication of a study by US researchers, who suggested that the levels of organic pollutants, including dioxins and PCBs, in farmed salmon could pose a health risk. Their advice to consume less than one half portion of farmed salmon (from specific areas) per month was in direct contrast to advice from food authorities to eat one portion of oily fish per week. This study did not, however, present new data as levels of contaminants were consistent with those previously reported in smaller studies and remained within internationally accepted safety guidelines. The discrepancy arose because the authors based their advice on a method of risk analysis that is not internationally accepted by toxicologists and other food safety experts. Food safety authorities in Europe and in the USA agreed that the study did not raise new health concerns and that eating one portion of farmed salmon per week was still considered safe." [35] and was followed by these words of advice " The consumer’s decision to include or exclude any food from the diet should be based on informed science rather than media headlines." [36]

Impact on wild salmonids

Farmed salmonids can, and often do, escape from sea cages. If the farmed salmonid is not native, it can compete with native wild species for food and habitat.[37][38][39] If the farmed salmonid is native, it can interbreed with the wild native salmonids. Such interbreeding can reduce genetic diversity, disease resistance and adaptability.[40] In 2004, about 500,000 salmon and trout escaped from ocean net pens off Norway. Around Scotland, 600,000 salmon were released during storms.[8] Commercial fishermen targeting wild salmon not infrequently catch escaped farm salmon. At one stage, in the Faroe Islands, 20 to 40 percent of all fish caught were escaped farm salmon.[41]

Sea lice, particularly Lepeophtheirus salmonis and various Caligus species, including Caligus clemensi and Caligus rogercresseyi, can cause deadly infestations of both farm-grown and wild salmon.[42][43] Sea lice are naturally occurring and abundant ectoparasites which feed on mucous, blood, and skin, and migrate and latch onto the skin of salmon during planktonic nauplii and copepodite larval stages, which can persist for several days.[44][45][46] Large numbers of highly populated, open-net salmon farms can create exceptionally large concentrations of sea lice; when exposed in river estuaries containing large numbers of open-net farms, many young wild salmon are infected, and do not survive as a result.[47][48] Adult salmon may survive otherwise critical numbers of sea lice, but small, thin-skinned juvenile salmon migrating to sea are highly vulnerable. In 2007, mathematical studies of data available from the Pacific coast of Canada indicated the louse-induced mortality of pink salmon in some regions was over 80%.[49] Later that year ,in reaction to the 2007 mathematical study mentioned above, Canadian federal fisheries scientists Kenneth Brooks and Simon Jones published a critique titled "Perspectives on Pink Salmon and Sea Lice: Scientific Evidence Fails to Support the Extinction Hypothesis "[50] The time since these studies has shown a general increase in abundance of Pink Salmon in the Broughton Archipelago. Another comment in the scientific literature by Canadian Government Fisheries scientists Brian Riddell and Richard Beamish et al came to the conclusion that there is no correlation between farmed salmon louse numbers and returns of pink salmon to the Broughton Archipelago. And in relation to the 2007 Krkosek extinction theory:"the data was used selectively and conclusions do not match with recent observations of returning salmon" [51]

A 2008 meta-analysis of available data shows that salmonid farming reduces the survival of associated wild salmonid populations. This relationship has been shown to hold for Atlantic, steelhead, pink, chum, and coho salmon. The decrease in survival or abundance often exceeds 50 percent.[52] However, these studies are all correlation analysis and correlation doesn't equal causation, especially when similar salmon declines were occurring in Oregon and California, which have no salmon aquaculture or marine net pens. Independent of the predictions of the failure of salmon runs in Canada indicated by these studies, the wild salmon run in 2010 was a record harvest.[53]

A 2010 study that made the first use of sea lice count and fish production data from all salmon farms on the Broughton Archipelago found no correlation between the farm lice counts and wild salmon survival. The authors conclude that the 2001 stock collapse was not caused by the farm sea lice population.The study found that the farm sea lice population during the out-migration of juvenile pink salmon was greater in 2000 than that of 2001, but a record salmon escapement in 2001 exonerates sea lice of the year 2002 collapse due to the absence of negative correlation. The authors also note that initial studies had not investigated bacterial and viral causes for the event despite reports of bleeding at the base of the fins, a symptom often associated with infections but not with sea lice exposure under laboratory conditions.[54]

Wild salmon are anadromous. They spawn inland in fresh water and when young migrate to the ocean where they grow up. Most salmon return to the river where they were born, although some stray to other rivers. There is concern about of the role of genetic diversity within salmon runs. The resilience of the population depends on some fish being able to survive environmental shocks, such as unusual temperature extremes. It is also unclear what the effect of hatchery production has been on the genetic diversity of salmon.[5]

Genetic modification

Main article: Genetically modified salmon

Salmon have been genetically modified in laboratories so they can grow faster. There is opposition to the commercial use of these fish, and, so far, no approval has been given.[55] A Canadian company, Aqua Bounty Farms, has developed a modified Atlantic salmon which grows several times faster (yielding a fully grown fish at 16–18 months rather than 30), and is more disease resistant and cold tolerant. It also requires 10% less food. This was achieved using a chinook salmon gene sequence affecting growth hormones, and a promoter sequence from the ocean pout affecting antifreeze production.[56] Normally, salmon produce growth hormones only in the presence of light. The modified salmon doesn't switch growth hormone production off. The company first submitted the salmon for FDA approval in 1996.[57][58] A concern with transgenic salmon is what might happen if they escape into the wild. One study, in a laboratory setting, found that modified salmon mixed with their wild cohorts were aggressive in competing, but ultimately failed.[59]

Impact on forage fish

The use of forage fish for fish meal production has been almost a constant for the last thirty years and at the maximum sustainable yield, while the market for fish meal has shifted from chicken, pig and pet food to aquaculture diets.[11] The fact that this market shift at constant production is an economic decision having no impact on the forage fish harvest rates for fish meal implies that the development of salmon aquaculture had no impact on forage fish harvest rates.

Fish do not actually produce omega-3 fatty acids, but instead accumulate them from either consuming microalgae that produce these fatty acids, as is the case with forage fish like herring and sardines, or, as is the case with fatty predatory fish, like salmon, by eating prey fish that have accumulated omega-3 fatty acids from microalgae. To satisfy this requirement, more than 50 percent of the world fish oil production is fed to farmed salmon.[15]

In addition, salmon require nutritional intakes of protein, protein which is often supplied to them in the form of fish meal as the lowest cost alternative protein. Consequently, farmed salmon consume more fish than they generate as a final product. To produce one pound of farmed salmon, products from several pounds of wild fish are fed to them. As the salmon farming industry expands, it requires a higher percentage of the wild forage fish for feed, at a time when seventy five percent of the worlds monitored fisheries are already near to or have exceeded their maximum sustainable yield.[8]

Salmon Aquaculture Dialogue

In 2004 the World Wide Fund for Nature (WWF) initiated the Salmon Aquaculture Dialogue.[7] The aim of the dialogue is to produce an environmental standard for farmed salmon by 2010. The WWF have identified what they call "seven key environmental and social impacts", which they characterise as follows

“1. Benthic impacts and siting: Chemicals and excess nutrients from food and feces associated with salmon farms can disturb the flora and fauna on the ocean bottom (benthos).[60]

2. Chemical inputs: Excessive use of chemicals - such as antibiotics, anti-foulants and pesticides - or the use of banned chemicals can have unintended consequences for marine organisms and human health.[61]

3. Disease/parasites: Viruses and parasites can transfer between farmed and wild fish, as well as among farms.[62][63]

4. Escapes: Escaped farmed salmon can compete with wild fish and interbreed with local wild stocks of the same population, altering the overall pool of genetic diversity.[64]

5. Feed: A growing salmon farming business must control and reduce its dependency upon fishmeal and fish oil - a primary ingredient in salmon feed - so as not to put additional pressure on the world's fisheries. Fish caught to make fishmeal and oil currently represent one-third of the global fish harvest.[65]

6. Nutrient loading and carrying capacity: Excess food and fish waste in the water have the potential to increase the levels of nutrients in the water. This can cause the growth of algae, which consumes oxygen that is meant for other plant and animal life.[66]

7. Social issues: Salmon farming often employs a large number of workers on farms and in processing plants, potentially placing labor practices and worker rights under public scrutiny. Additionally, conflicts can arise among users of the shared coastal environment.”

—WWF, [7]

Hatch and release[edit]

Another form of salmon production, which is safer but less controllable, is to raise salmon in hatcheries until they are old enough to become independent. They are then released into rivers, often in an attempt to increase the salmon population. This practice was very common in countries like Sweden before the Norwegians developed salmon farming, but is seldom done by private companies, as anyone may catch the salmon when they return to spawn, limiting a company's chances of benefiting financially from their investment. Because of this, the method has mainly been used by various public authorities and non profit groups like the Cook Inlet Aquaculture Association as a way of artificially increasing salmon populations in situations where they have declined due to overharvest, construction of dams, and habitat destruction or disruption. Unfortunately, there can be negative consequences to this sort of population manipulation, including genetic "dilution" of the wild stocks, and many jurisdictions are now beginning to discourage supplemental fish planting in favour of harvest controls and habitat improvement and protection. A variant method of fish stocking, called ocean ranching, is under development in Alaska. There, the young salmon are released into the ocean far from any wild salmon streams. When it is time for them to spawn, they return to where they were released where fishermen can then catch them.

Species

Atlantic salmon

In their natal streams, Atlantic salmon are considered a prized recreational fish, pursued by avid fly anglers during its annual runs. At one time, the species supported an important commercial fishery and a supplemental food fishery. However, the wild Atlantic salmon fishery is commercially dead; after extensive habitat damage and overfishing, wild fish make up only 0.5% of the Atlantic salmon available in world fish markets. The rest are farmed, predominantly from aquaculture in Chile, Canada, Norway, Russia, the UK and Tasmania in Australia.[67]

Atlantic salmon is, by far, the species most often chosen for farming. It is easy to handle, it grows well in sea cages, commands a high market value and it adapts well to being farmed away from its native habitats.[5]

Adult male and female fish are anesthetized. Eggs and sperm are "stripped", after the fish are cleaned and cloth dried. Sperm and eggs are mixed, washed, and placed into fresh water. Adults recover in flowing, clean, well aerated water.[68] Some researchers have studied cryopreservation of the eggs.[69]

Fry are generally reared in large freshwater tanks for 12 to 20 months. Once the fish have reached the smolt phase, they are taken out to sea where they are held for up to two years. During this time the fish grow and mature in large cages off the coasts of Canada, the United States, or parts of Europe.[67] Generally, cages are made of two nets; inner nets, which wrap around the cages, hold the salmon while outer nets, which are held by floats, keep predators out.[68]

Many Atlantic salmon escape from cages at sea. Those salmon who further breed tend to lessen the genetic diversity of the species leading to lower survival rates, and lower catch rates. On the West Coast of Northern America, the non-native salmon can be an invasive threat, especially in Alaska and parts of Canada. This causes them to compete with native salmon for resources. Extensive efforts are underway to prevent escapes and the spread of Atlantic salmon in the Pacific and elsewhere.[70]

In 2007, 1,433,708 tonnes of Atlantic salmon were harvested worldwide with a value of $7.58 billion.[71]

Steelhead

Rainbow trout

Male ocean phase steelhead salmon

In 1989 steelhead was a classified as Oncorhynchus mykiss, a Pacific trout. Steelhead are an anadromous form of rainbow trout that migrates between lakes and rivers and the ocean, and are also known as steelhead salmon or ocean trout.

Steelhead are raised in many countries throughout the world. Since the 1950s production has grown exponentially, particularly in Europe and recently in Chile. Worldwide, in 2007, 604,695 tonnes of farmed Steelhead were harvested with a value of $2.59 billion.[72] The largest producer is Chile. In Chile and Norway, the ocean cage production of steelhead has expanded to supply export markets. Inland production of rainbow trout to supply domestic markets has increased strongly in countries such as Italy, France, Germany, Denmark, and Spain. Other significant producing countries include the United States, Iran, Germany, and the UK.[72]

Steelhead have tender flesh and a mild, somewhat nutty flavour. Steelhead meat is pink like that of other salmon, and is more flavourful than the light-coloured meat of rainbow trout.[73] Both are highly desired food. However, farmed trout and those taken from certain lakes have a pronounced earthy flavour which many people find unappealing; many shoppers therefore make it a point to ascertain the source of the fish before buying. Steelhead that are wild have a diet of scuds (freshwater shrimp), insects such as flies, and crayfish are the most appealing. Dark red/orange meat indicates that it is either an anadromous steelhead or a farmed rainbow trout given a supplemental diet with a high iodine content. The resulting pink flesh is marketed under monikers like Ruby Red or Carolina Red.

The steelhead is especially susceptible to enteric redmouth disease. There has been considerable research conducted on redmouth disease, as its implications for steelhead farmers are significant. The disease does not affect humans.[74]

Coho salmon

Male ocean phase Coho salmon

The Coho salmon[9] is the state animal of Chiba, Japan.

Coho salmon mature after only one year in the sea, so two separate broodstocks (spawners) are needed, alternating each year. Broodfish are selected from the salmon in the seasites and "transferred to freshwater tanks for maturation and spawning".[9]

Worldwide, in 2007, 115,376 tonnes of farmed Coho salmon were harvested with a value of $456 million.[75] Chile, with about 90% of world production, is the primary producer with Japan and Canada producing the rest.[9]

Chinook salmon

male ocean phase Chinook

male freshwater phase Chinook

In Alaska, Chinook salmon are the state fish, and are known as "king salmon" because of their large size and flavourful flesh. Those from the Copper River in Alaska are particularly known for their colour, rich flavour, firm texture, and high Omega-3 oil content.[76]Alaska has a long standing ban on finfish aquaculture that was enacted in 1989. Alaska Stat. § 16.40.210 [77]

Worldwide, in 2007, 11,542 tonnes of farmed Chinook salmon were harvested with a value of $83 million.[78] New Zealand is the largest producer of farmed king salmon, accounting for over half of world production (7,400 tonnes in 2005).[79] Most of the salmon are farmed in the sea (mariculture) using a method sometimes called sea-cage ranching. Sea-cage ranching takes place in large floating net cages, about 25 metres across and 15 metres deep, moored to the sea floor in clean, fast-flowing coastal waters. Smolt (young fish) from freshwater hatcheries are transferred to cages containing several thousand salmon, and remain there for the rest of their life. They are fed fishmeal pellets high in protein and oil.[79]

King salmon are also farmed in net cages placed in freshwater rivers or raceways, using techniques similar to those used for sea-farmed salmon. A unique form of freshwater salmon farming occurs in some hydroelectric canals. A site in Tekapo, fed by fast cold waters from the Southern Alps, is the highest salmon farm in the world, 677 metres above sea level.[80]

Before they are killed, cage salmon are anaesthetised with a herbal extract. They are then spiked in the brain. The heart beats for a time as the animal is bled from its sliced gills. This method of relaxing the salmon when it is killed produces firm, long-keeping flesh.[79] Lack of disease in wild populations and low stocking densities used in the cages means that New Zealand salmon farmers do not use antibiotics and chemicals that are often needed elsewhere.[81]

Timeline

1527: The life history of the Atlantic salmon is described by Hector Boece of the University of Aberdeen, Scotland.[56]

1763: Fertilization trials for Atlantic salmon take place in Germany. Later biologists refined these in Scotland and France.[56]

1854: Salmon spawing beds and rearing ponds built along the bank of a river by the Dohulla Fishery, Ballyconneely, Ireland.[82]

Late 19th century: Salmon hatcheries are used in Europe, North America, and Japan to enhance wild populations.

Late 1960s: First salmon farms established in Norway and Scotland.

Early 1970s: Salmon farms established in North America.

1975: Gyrodactylus, a small monogenean parasite, spreads from Norwegian hatcheries to wild salmon, probably by means of fishing gear, and devastates some wild salmon populations.[20]

Late 1970s: Salmon farms established in Chile and New Zealand.

1984: Infectious salmon anemia, a viral disease, is discovered in a Norwegian salmon hatchery. Eighty percent of the involved fish die.

1985: Salmon farms established in Australia.

1987: First reports of escaped Atlantic salmon being caught in wild Pacific salmon fisheries.

1988: A storm hits the Faroes Islands releasing millions of Atlantic salmon.

1989: Furunculosis, a bacterial disease, spreads through Norwegian salmon farms and wild salmon.

Early 1990s: Sea lice from Atlantic salmon farms infest wild sea trout around Ireland, resulting in the collapse of their fisheries.

1996: World farmed salmon production exceeds wild salmon harvest.

2007: A 10-square-mile (26 km2) swarm of Pelagia noctiluca jellyfish wipes out a 100,000 fish salmon farm in Northern Ireland.[83]

Notes

1. Based on data sourced from the relevant FAO Species Fact Sheets

2. FAO: World Review of Fisheries and Aquaculture 2008 Rome.

3. KT Pirquet (2010) "Follow the Money", Aquaculture North America, vol 16, May/June 2010 [1]

4. Jump up ^ Alaska Department of Fish and Game [2]

5. Knapp G, Roheim CA and Anderson JL (2007) The Great Salmon Run: Competition Between Wild And Farmed Salmon World Wildlife Fund. ISBN 0-89164-175-0

6. Sea Lice and Salmon: Elevating the dialogue on the farmed-wild salmon story Watershed Watch Salmon Society, 2004.

7. WWF: Aquaculture: Salmon Retrieved 12 May 2009.

8. Seafood Choices Alliance (2005) It's all about salmon

9. FAO: Cultured Aquatic Species Information Programme: Oncorhynchus kisutch (Walbaum, 1792) Rome. Retrieved 8 May 2009.

10. Naylor, RL (2005) "Search for Sustainable Solutions in Salmon Aquaculture" Stanford University.

11. Ocean Stewards report with graph on supply as a function of time

12. Merrit, Mike (13 January 2013) Sea-change as farm grows fish on land The Scotsman, Retrieved 22 January 2013

13. Kadir Alsagoff, S. A., H. A. Clonts, et al. (1990). "An integrated poultry, multi-species aquaculture for Malaysian rice farmers: A mixed integer programming approach." Agricultural Systems 32(3): 207-231 [3]

14. Bell, J. G., J. Pratoomyot, et al. (2010). "Growth, flesh adiposity and fatty acid composition of Atlantic salmon (Salmo salar) families with contrasting flesh adiposity: Effects of replacement of dietary fish oil with vegetable oils." Aquaculture 306(1-4): 225-232 [4]

15. FAO: World Review of Fisheries and Aquaculture 2008: Highlights of Special Studies Rome.

16. "Pigments in Salmon Aquaculture: How to Grow a Salmon-coloured Salmon". Retrieved 2007-08-26. "Astaxanthin (3,3'-hydroxy-β,β-carotene-4,4'-dione) is a carotenoid pigment, one of a large group of organic molecules related to vitamins and widely found in plants. In addition to providing red, orange, and yellow colours to various plant parts and playing a role in photosynthesis, carotenoids are powerful antioxidants, and some (notably various forms of carotene) are essential precursors to vitamin A synthesis in animals."

17. Naylor, Rosamond L. "Nature's Subsidies to Shrimp and Salmon Farming" (PDF). Science; 10/30/98, Vol. 282 Issue 5390, p883.

18. Modern Salmon Harvest (2010)

19. FAO: Species fact sheets Rome.

20. Stead, SM and Laird lLM (2002) Handbook of salmon farming, page 348, Birkhäuser. ISBN 978-1-85233-119-1

21. New Brunswick to help Chile beat disease Fish Information and Services

22. Fact Sheet - Atlantic Salmon Aquaculture Research Fisheries and Oceans Canada. Retrieved 12 May 2009.

23. Scientific Evidence.

24. Krkosek M, Ford JS, Morton A, Lele S, Myers RA and Lewis MA (2007) Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon Science, 318, 5857: 1772.]

25. Riddell, B. E., R. J. Beamish, et al. (2008). "Comment on "Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon"." Science 322(5909): 1790b [5]

26. Lang SS (2005) "Stick to wild salmon unless heart disease is a risk factor, risk/benefit analysis of farmed and wild fish shows" Chronicle Online, Cornell University.

27. Hites RA, Foran JA, Carpenter DO, Hamilton C, Knuth BA and Schwager SJ (2004) "Global Assessment of Organic Contaminants in Farmed Salmon" Science, 303 (5655) 226–229.

28. Schwager SJ (2005) "Risk-based consumption advice for farmed Atlantic and wild Pacific Salmon contaminated with dioxins and dioxin-like compounds" Environmental Health Perspectives, May 1.

29. Hamilton MC, Hites RA, Schwager SJ, Foran JA, Knuth BA and Carpenter DO (2005) "Lipid Composition and Contaminants in Farmed and Wild Salmon" Environmental Science and Technology, 39 (22), pp 8622–8629

30. Jeffery A, Foran DH, Good DH, Carpenter DO, Hamilton CM, Knuth BA and Schwager SJ (2005) "Quantitative Analysis of the Benefits and Risks of Consuming Farmed and Wild Salmon" The Journal of Nutrition 135 : 2639-2643.

31. http://www.hc-sc.gc.ca/fn-an/securit/chem-chim/environ/mercur/servey_sondage-eng.php

32. http://www.hc-sc.gc.ca/fn-an/food-guide-aliment/choose-choix/meat-viande/index-eng.php

33. http://www.health.gov/dietaryguidelines/

34. http://www.efsa.europa.eu/en/efsajournal/pub/2832.htm

35. http://www.eufic.org/article/en/food-safety-quality/food-contaminants/artid/contaminants-in-fish/

36. http://www.eufic.org/article/en/food-safety-quality/food-contaminants/artid/contaminants-in-fish/

37. Fleming, I.A. et al. 2000. Proceedings of the Royal Society of London, Ser. B 267:1517.

38. Volpe, J.P., B.R. Anholt, B.W. Glickman. 2001. Canadian Journal of Fisheries and Aquatic Sciences 58:197.

39. Volpe, J.P., E.B. Taylor, D.W. Rimmer, B.W. Glickman. 2000. Evidence of natural reproduction of aquaculture-escaped Atlantic salmon in a coastal British Columbia river. Conservation Biology 14(3):899-903.

40. Gardner J and DL Peterson (2003) "Making sense of the aquaculture debate: analysis of the issues related to netcage salmon farming and wild salmon in British Columbia", Pacific Fisheries Resource Conservation Council, Vancouver, BC.

41. Hansen LP, JA Jacobsen and RA Lund (1998) "The incidence of escaped farmed Atlantic salmon, Salmo salar L., in the Faroese fishery and estimates of catches of wild salmon", ICES Journal of Marine Science, 56(2): p. 200-206.

42. Sea Lice and Salmon: Elevating the dialogue on the farmed-wild salmon story Watershed Watch Salmon Society, 2004.

43. Bravo, S. (2003). "Sea lice in Chilean salmon farms". Bull. Eur. Assoc. Fish Pathol. 23, 197–200.

44. Morton, A., R. Routledge, C. Peet, and A. Ladwig. 2004 Sea lice (Lepeophtheirus salmonis) infection rates on juvenile pink (Oncorhynchus gorbuscha) and chum (Oncorhynchus keta) salmon in the nearshore marine environment of British Columbia, Canada. Canadian Journal of Fisheries and Aquatic Sciences 61:147–157.

45. Peet, C. R. 2007. Thesis, University of Victoria.

46. Krkošek, M., A. Gottesfeld, B. Proctor, D. Rolston, C. Carr-Harris, M.A. Lewis. 2007. Effects of host migration, diversity, and aquaculture on disease threats to wild fish populations. Proceedings of the Royal Society of London, Ser. B 274:3141-3149.

47. Morton, A., R. Routledge, M. Krkošek. 2008. Sea louse infestation in wild juvenile salmon and Pacific herring associated with fish farms off the east-central coast of Vancouver Island, British Columbia. North American Journal of Fisheries Management 28:523-532.

48. Krkošek, M., M.A. Lewis, A. Morton, L.N. Frazer, J.P. Volpe. 2006. Epizootics of wild fish induced by farm fish. Proceedings of the National Academy of Sciences 103:15506-15510.

49. Krkošek, Martin, et al. Report: "Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon", Science: Vol. 318. no. 5857, pp. 1772 - 1775, 14 December 2007. PDF

50. http://www.tandfonline.com/doi/abs/10.1080/10641260801937131#.UtHiIfRDsQc

51. http://www.sciencemag.org/content/322/5909/1790.2.full

52. Ford JS and Myers RA (2008) doi:10.1371/journal.pbio.0060033 "A Global Assessment of Salmon Aquaculture Impacts on Wild Salmonids" PLoS Biol, 6(2): e33.

53. Canada sees shock salmon glut

54. Marty GD, Saksidab SM and Quinn II TJ (2012) "Relationship of farm salmon, sea lice, and wild salmon populations" PNAS, 109 (21). doi:10.1073/pnas.1009573108

55. Mcleod C, J Grice, H Campbell and T Herleth (2006) Super Salmon: The Industrialisation of Fish Farming and the Drive Towards GM Technologies in Salmon Production CSaFe, Discussion paper 5, University of Otago.

56. Knapp G, Roheim CA and Anderson JA (2007) Chapter 5: The World Salmon Farming Industry in The Great Salmon Run, Report of the Institute of Social and Economic Research, University of Alaska Anchorage. ISBN 0-89164-175-0.

57. Salmon That Grow Up Fast Business Week, 16 January 2006.

58. Fast Growing GM Salmon Swims Close to US Markets The Fish Site, 11 February 2009.

59. Devlin RH, D'Andrade M, Uh M and Biagi CA (2004) "Population effects of growth hormone transgenic coho salmon depend on food availability and genotype by environment interactions", Proceedings of the National Academy of Sciences, 101(25)9303-9308.

60. WWF: Salmon Aquaculture Dialogue: Benthic impacts report

61. WWF: Salmon Aquaculture Dialogue: Chemical report

62. WWF: Salmon Aquaculture Dialogue: Disease report

63. WWF: Salmon Aquaculture Dialogue: Sealice report

64. WWF: Salmon Aquaculture Dialogue: Escapes report

65. WWF: Salmon Aquaculture Dialogue: Feed report

66. WWF: Salmon Aquaculture Dialogue: Nutrient loading

67. Heen, K. (1993). Salmon Aquaculture. Halstead Press.

68. Sedgwick, S. (1988). Salmon Farming Handbook. Fishing News Books LTD.

69. N. Bromage (1995). Broodstock Management and Egg and Larval Quality. Blackwell Science.

70. Mills, D. (1989). Ecology and Management of Atlantic Salmon. Springer-Verlag.

71. FAO: Species Fact Sheets: Salmo salar (Linnaeus, 1758) Rome. Accessed 9 May 2009.

72. FAO: Species Fact Sheets: Oncorhynchus mykiss (Walbaum, 1792) Rome. Accessed 9 May 2009.

73. Your Christmas Steelhead

74. LSC - Fish Disease Leaflet 82

75. FAO: Species Fact Sheets: Oncorhynchus kisutch (Walbaum, 1792) Rome. Accessed 9 May 2009.

76. Seattlest: Foodies...FREAK! Copper River Salmon Arrive

77. http://codes.lp.findlaw.com/akstatutes/16/16.40./03./16.40.210.

78. FAO: Species Fact Sheets: Oncorhynchus tshawytscha (Walbaum, 1792) Rome. Accessed 9 May 2009.

79. Marine Aquaculture MFish. Updated 16 November 2007.

80. Wassilieff, Maggy Aquaculture: Salmon Te Ara - the Encyclopedia of New Zealand, updated 21 September 2007

81. Aquaculture in New Zealand aquaculture.govt.nz

82. History of Ballyconneely from earliest settlers to the present day connemara.net. Retrieved 26 May 2009.

83. "Billions of jellyfish wipe out salmon farm". MSNBC. November 21, 2007. Retrieved 28 January 2010.

References

84. Beveridge, Malcolm (1984) Cage and Pen fish farming: Carrying capacity models and environmental impact FAO Fisheries technical paper 255, Rome. ISBN 92-5-102163-5

85. Bjorndal, Trond (1990) The Economics of Salmon Aquaculture. Wiley-Blackwell. ISBN 978-0-632-02704-0

86. Coimbra, João (2001) Modern aquaculture in the coastal zone: lessons and opportunities IOS Press. ISBN 978-0-9673355-6-8

87. Harris G and Milner N (Eds) (2004) Sea Trout: Biology, Conservation, and Management Proceedings of First International Sea Trout Symposium, Cardiff, July 2004. Wiley-Blackwell. ISBN 978-1-4051-2991-6

88. Heen K, Monahan RL and Utter F (1993) Salmon Aquaculture, Wiley-Blackwell. ISBN 978-0-85238-204-2

89. Knapp G, Roheim CA and Anderson JA (2007) The Great Salmon Run: Competition between Wild and Farmed Salmon Report of the Institute of Social and Economic Research, University of Alaska Anchorage. ISBN 0-89164-175-0.

90. Lombardo PA Bostrom A (2008) "Swimming upstream: Regulating Genetically Modified Salmon in Altering Nature, Eds: Lustig BA, Brody BA and McKenny GP, Springer. ISBN 978-1-4020-6922-2

91. Pomeroy R, Bravo-Ureta BE, Solis D and Johnston RJ (2008) "Bioeconomic modelling and salmon aquaculture: an overview of the literature" International Journal of Environment and Pollution 33(4) 485–500.

92. Quinn, Thomas P (2005) The behavior and ecology of Pacific salmon and trout University of Washington Press. ISBN 978-0-295-98457-5

93. British Columbia Salmon Farming Association, "Did you Know" [6]

94. Further reading[edit]

95. Framing the Fish Farmers: The Impact of Activists on Media and Public Opinion about the Aquaculture Industry Atlantic Institute for Market Studies, 2004.

96. Myths and Realities about Salmon Farming Fisheries and Oceans Canada, 2005.

97. Sea Lice and Salmon: Elevating the dialogue on the farmed-wild salmon story Watershed Watch Salmon Society, 2004.

98. External links

99. Wikimedia Commons has media related to Salmonidae.

100. Aquaculture: Salmon - World Wildlife Fund

101. BC Salmon Facts Salmon farming industry site explaining salmon farming in British Columbia, Canada.

102. BC Salmon Farmers Association Association representing salmon farmers in British Columbia, Canada.

103. CAIA – Canadian Industry Aquaculture Association Canadian association representing all salmon farms in Canada.

104. Disease-Related Impacts of Salmon Aquaculture - World Wildlife Fund press release

105. Salmon Aquaculture – David Suzuki Foundation brochure

106. Watershed Watch Salmon Society

107. Wild Salmon in Trouble: The Link Between Farmed Salmon, Sea Lice and Wild Salmon - Watershed Watch Salmon Society. Animated short video based on peer-reviewed scientific research.

108. Aquacultural Revolution: The scientific case for changing salmon farming - Watershed Watch Salmon Society. Short video documentary by filmmakers Damien Gillis and Stan Proboszcz. Prominent scientists and First Nation representatives speak their minds about the salmon farming industry and the effects of sea lice infestations on wild salmon populations.

109. Positive Aquaculture Awareness Independent association which promotes salmon farming in British Columbia, Canada.

110. Farmed and dangerous - Salmon Farming Problems – Coastal Alliance for Aquaculture Reform

111. Sea Lice - Coastal Alliance for Aquaculture Reform. An overview of farmed- to wild-salmon interactive effects.

112. What about this fish? – Video extract from Harvest of Fear.

113. Fish farms drive wild salmon populations toward extinction Biology News Net. December 13, 2007.

114. Brooks K. and Jones S. (2008) "Perspectives on pink salmon and sea lice: Scientific evidence fails to support the extinction hypothesis" Reviews in Fisheries Science, 16 (4): 403–412.

115. Salmonid parasites University of St Andrews Marine Ecology Research Group.

116. Salmon

117. Groups and species

118. Salmon Salmonidae Adriatic salmon Atlantic salmon Black Sea salmon Pacific salmon Chum salmon Chinook salmon Coho salmon June hogs Masu salmon Pink salmon Steelhead Satsukimasu salmon Sockeye salmon Taiwanese salmon Danube Salmon Sabertooth salmon Genetically modified salmon

119. Salmo salar GLERL 1.jpg

120. Fisheries and management

121. Aquaculture of salmon Fly fishing bibliography Environmental issues with salmon Old McKenzie Fish Hatchery Pre-spawn mortality in coho salmon Puget Sound salmon Putcher Putcher fishing Alaska salmon fishery Salmon conservation Salmon run

122. As food

123. Salmon (food) Cured salmon Gravlax Lohikeitto Lomi salmon Lox Poacher's Relish Rui-be Salmon burger Salmon cannery Salmon tartare Smoked salmon Images

124. Diseases and parasites

125. Diseases and parasites in salmon Amoebic gill disease Ceratomyxa shasta Gyrodactylus salaris Henneguya zschokkei Infectious salmon anemia virus M74 syndrome Myxobolus cerebralis Nanophyetus salmincola Salmon louse Sea louse Salmon tapeworm Sphaerothecum destruens Tetracapsuloides bryosalmonae

126. Organisations

127. Atlantic Salmon Federation Cook Inlet Aquaculture Association North Atlantic Salmon Conservation Organization Pacific Salmon Commission Welsh Salmon and Trout Angling Association Wild Salmon Center Yakima Klickitat Fisheries Project

Other

128. Ceasg Salmon (color) Salmon of Wisdom Salmon Fishing in the Yemen The Salmon Fly

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Mussel farming

Marine blue mussel, Mytilus edulis, showing some of the inner anatomy.

The white posterior adductor muscle is visible in the upper image, and has been cut in the lower image to allow the valves to open fully.

Aquaculture

Main producer countries, FAO 2006

Mussel output in 2005.

Mussel dredgers

Bouchots are marine pilings for growing mussels, here shown at an agricultural fair.

Bamboo is used for mussels breeding and propagation (Abucay, Bataan, Philippines).

In 2005, China accounted for 40 per cent of the global mussel catch according to a FAO study.[1] Within Europe, where mussels have been cultivated for centuries, Spain remained the industry leader. Aquaculture of mussels in North America began in the 1970′s.[2] In the U.S, the northeast and northwest have significant mussel aquaculture operations, where Mytilus edulis (blue mussel) is most commonly grown. While the mussel industry in the U.S. has increased, in North America, 80% of cultured mussels are still produced in Prince Edward Island in Canada.[3] In Washington (state), an estimated 2.9M pounds of mussels were harvested in 2010 valuing roughly $4.3M.[4]

Culture Methods Freshwater mussels are used as host animals for the cultivation of freshwater pearls. Some species of marine mussel, including the Blue Mussel (Mytilus edulis) and the New Zealand green-lipped mussel (Perna canaliculus), are also cultivated as a source of food.

Mussel production cycle, FAO 2006

In some areas of the world, mussel farmers collect naturally occurring marine mussel seed for transfer to more appropriate growing areas, however, most North American mussel farmers rely on hatchery-produced seed.[2] Growers typically purchase seed after it has set (about 1mm in size) or after it has been nursed in upwellers for 3-6 additional weeks and is 2-3mm.[2] The seed is then typically reared in a nursery environment, where it is transferred to a material with a suitable surface for later relocation to the growing area. After about three months in the nursery, mussel seed is “socked” (placed in a tube-like mesh material) and hung on longlines or rafts for grow-out. Within a few days, the mussels migrate to the outside of the sock for better access food sources in the water column. Mussels grow quickly and are usually ready for harvest in less than two years. Unlike other cultured bivalves, mussels use byssus threads (beard) to attach themselves to any firm substrate, which makes them suitable for a number of culture methods. There are a variety of techniques for growing mussels.

Bouchot culture: Intertidal growth technique, or bouchot technique: pilings, known in French as bouchots, are planted at sea; ropes, on which the mussels grow, are tied in a spiral on the pilings; some mesh netting prevents the mussels from falling away. This method needs an extended tidal zone.

On-bottom culture: On-bottom culture is based on the principle of transferring mussel seed (spat) from areas where they have settled naturally to areas where they can be placed in lower densities to increase growth rates, facilitate harvest, and control predation (Mussel farmers must remove predators and macroalgae during the growth cycle).[2]

Raft culture: Raft culture is a commonly used method throughout the world. Lines of rope mesh socks are seeded with young mussels and suspended vertically from a raft. The specific length of the socks depends on depth and food availability.

Longline culture (rope culture): Mussels are cultivated extensively in New Zealand, where the most common method is to attach mussels to ropes which are hung from a rope back-bone supported by large plastic floats. The most common species cultivated in New Zealand is the New Zealand green-lipped mussel. Longline culture is the most recent development for mussel culture[2] and are often used as an alternative to raft culture in areas that are more exposed to high wave energy. A long-line is suspended by a series of small anchored floats and ropes or socks of mussels are then suspended vertically from the line.

Harvest: In roughly 12–15 months, mussels reach marketable size (40mm) and are ready for harvest (FAO). Harvesting methods depend on the grow-out area and the rearing method being used. Dredges are currently used for on-bottom culture. Mussels grown on wooden poles can be harvested by hand or with a hydraulic powered system (FAO). For raft and longline culture, a platform is typically lowered under the mussel lines, which are then cut from the system and brought to the surface and dumped into containers on a nearby vessel. After harvest, mussels are typically placed in seawater tanks for depuration before marketing.

References

1. China catches 0.77m tonnes of mussels in 2005

2. "Mussel Culture in British Columbia". BC Shellfish Growers Association.

3. Calta, Marialisa (August 28, 2005). "Mussels on Prince Edward Island". New York Times. Retrieved April 26, 2009.

4. Northern Economics, Inc. "The Economic Impact of Shellfish Aquaculture in Washington, Oregon and California". Prepared for Pacific Shellfish Institute. Retrieved April 2013.

5. FAO 2006. Mytilus edulis fishery http://www.fao.org/fishery/culturedspecies/Mytilus_edulis/en

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