Seaweed Farming

Table of Contents

Introduction

Unlike the types of aquaculture focused on mass producing fish or other animals, seaweed farming actually helps reverse our impact on the planet in a number of ways. Seaweed helps sequester carbon, remove pollutants and excess nutrition from the ocean, and can even provide habitat for wildlife if done outdoors instead of an indoor facility.

Just like any other possitivie solution, there can also be drawbacks to consider, such as the possibility of introducing invasive species if farmers introduce non-native species to their farms. There's also the possibility of damaging local ecosystems in seaweed is staked in delicate ecosystems with certain types of substrate.

Global State of Seaweed Farming

"Seaweed is a greatly underestimated resource that provides food and shelter to marine life. It is also used as a food source for people - often referred to as a ‘superfood’ that is rich in iodine and calcium and contains natural antioxidants, minerals and amino acids. Seaweed is also an important source for future supply of food and feed (additives), pharmaceuticals, cosmetics, biomaterials and bioenergy.

Seaweed farming is a mature multi-billion dollar industry and some Asian countries produce tens of millions of tonnes a year. But although seaweed grows prolifically in Scottish waters, seaweed farming in the UK is only in its early stages as an emerging industry." - SAMS: Seaweed Farms  

Benefits of Seaweed Farming

For Farmers

"For shellfish and finfish farmers, commercial fishermen, and first-time farmers, seaweed offers an opportunity to diversify a farming operation or start a new business. Seaweeds use the entire water column. This means farmers can grow seaweed using a process known as vertical, or 3D, farming—and reap large harvests from a small area. Most seaweeds grow on longlines suspended around 4–8 feet below the surface throughout the winter. Their blades will reach 10 feet or more before they are harvested in the spring." - NOAA Fisheries: Seaweed Aquaculture 

Low investment & Opportunity for Improved Standard of Living

"It doesn’t cost a lot to get started as a seaweed farmer, which means barriers are relatively low for smallholders. Some research indicates that poor regions that have begun seaweed farming have seen increased standards of living and food security."  - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism 

Ecological Impacts

"Kelp forests are a valuable coastal habitat in temperate areas throughout the world. In Puget Sound, bull kelp has declined extensively. NOAA is working with local partners to use restoration aquaculture approaches to regenerate these large, fast-growing kelps. The seaweeds create forage and refuge habitat for commercially important fish and diversity of marine life. 

Seaweeds also act as a sponge soaking up what’s in the water. These marine plants could potentially be cultivated to reduce heavy metals and other coastal pollutants. Unlike in commercial seaweed farming, the seaweeds grown for this reason would never be eaten. Instead, communities and other stakeholders could establish seaweed farms in polluted areas with the sole aim of improving the health of coastal ecosystems." - NOAA Fisheries: Seaweed Aquaculture 

Opportunity to Combat Dead Zones

"seaweed could be used to combat dead zones, since it soaks up excess nitrogen and phosphorus." - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism 

Carbon Sequestration

Ocean Acidification

"Seaweeds are incredibly efficient at sucking up carbon dioxide and using it to grow. Eelgrass, mangroves, and salt marshes are already known for their ability to store carbon. But seaweeds pull more of the greenhouse gas from the water than all three combined based on biomass. That means seaweed farms can help to combat local impacts of ocean acidification. " - NOAA Fisheries: Seaweed Aquaculture 

Reduced Water Pollution

"Seaweeds also gobble up nitrogen and phosphorus. In large quantities, these nutrients cause algal blooms that deplete the ocean of oxygen when they decompose. Excess nitrogen and phosphorus from stormwater runoff and point-sources are behind the dead zones that form in the Gulf of Mexico and Chesapeake Bay. Seaweed farms can help lower nutrient levels in nearby waters." - NOAA Fisheries: Seaweed Aquaculture 

Food Security & Nutrition

Historical & Cultural Recipes

Seaweeds, kelps and other sea "plants" have been important culinary ingredients throughout history, used all over the world including Japan, Scotland, North America, and Italy. Around the world, governments and farmers seek to help recover lost recipes and the cultural history they represent.

Protein & Nutrient Rich Food With Less Land or Other Imputes

"Seaweed farms have the capacity to grow massive amounts of nutrient-rich food. Professor Ronald Osinga, at Wageningen University in the Netherlands, has calculated that a global network of sea-vegetable farms totaling seventy thousand square miles - roughly the size of Washington state - could provide enough protein for the entire world population. And this is just the beginning, as there are more than ten thousand edible plants in the ocean." - Drawdown The Most Comprehensive Plan Ever Proposed to Reverse Global Warming" edited by Paul Hawken, 2017

Compatible with Multitrophic Aquaculture & Restoration Agriculture

"Multitrophic aquaculture" is the practice of growing a variety of aquaculture species that provide for and feed the others within said system.

"Farmers in Long Island Sound are diversifying small-scale organic shellfish farms with various species of seaweed to filter out the pollutants, mitigate oxygen depletion, and develop a sustainable source of fertilizer and fish meal. In Southern Spain, Veta la Palma designed its farm to restore wetlands, and in the process created the largest bird sanctuary in Spain, with more than 200 species of birds." - Drawdown The Most Comprehensive Plan Ever Proposed to Reverse Global Warming" edited by Paul Hawken, 2017

(Potential) Problems with Seaweed Farming

"While wild seaweed forests have been shown to absorb carbon dioxide, the amount of carbon that seaweed farms can sequester is not yet fully understood... And ventures looking to produce seaweed-based plastics, fuels, and proteins must contend with high production costs, making it hard for them to compete with the large industries they’re trying to disrupt. “There are some growing pains in terms of establishing those economies of scale that can then compete with these larger-scale global commodities,”..."  - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism 

Ethical Questions around Sinking Edible Seaweed Crops for Carbon Sequestration

"Sinking seaweed to remove carbon from the atmosphere is another area of active interest, but research suggests that it’s currently more economically feasible to use seaweed biomass than to sink it, said Feehan. And ethical questions about sinking a crop that could be used to feed people remain unaddressed, she said." - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism 

Risks to Farmers

"seaweed farmers also face risks — rates of respiratory illness may be higher among seaweed farmers, for example, likely due to inhaling dried seaweed. And while seaweed farming can provide a livelihood to women in poor areas, it also can put them in danger, since women in these communities are often less likely than men to know how to swim or handle boats, the report said. Seaweed shows promise as a nutritious food source, the report said, but it can also concentrate pollutants like heavy metals when it’s grown in contaminated water." - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism 

Improper Farm Placements Cause Ecological Decline

"in areas where nutrients are limited, seaweed may outcompete eelgrass and other native species for nutrients. Ultimately, whether seaweed farms increase or harm biodiversity may depend on where they are sited. In less complex ecosystems, like sandy bottom oceans, evidence suggests seaweed farms can boost biodiversity by providing habitat for marine life. But when seaweed farms are put into more diverse ecosystems, like eelgrass beds and coral reefs, these rich ecosystems tend to decline."  - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism 

Introducing Invasive Seaweed Species & Diseases

"Seaweed farms can also degrade marine ecosystems by spreading invasive species and disease. Non-native seaweed, in particular, has harmed coral reefs, seagrass meadows, and mangroves in places including Hawaii, Panama, and India." - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism  

Wildlife Entanglements

Standard "seaweed farms use rope, which poses a risk of entanglement to sea turtles and marine mammals." - The Fern AG Insider: As Seaweed Farming Expands UN Report Urges More Research Cautious Optimism 

Solutions

Further Research

By studying more species of seaweed, impacts on farmers and ecosystems, as well as other pertinent topics, we can increase efficiency while reducing undue ecological harm, harm to humans as well as tackling inequalities already present within the agriculture industry.

Researchers and developers can improve safety and training opportunities for farmers.

Reduce Impact on Wildlife

"Numerous studies show that seaweed farming has a low level of environmental risk, including entanglement.1, 2, 3, 4, 5, 6, 7, 9, 10..." - World Wildlife: Seaweed Farming Avoiding the Potential Risk of Entanglement 

With this in mind, simply switching from standard fishing practices to seaweed farming, can immediately reduce the impact of the food industry on our oceans. However there's always room for improvement, so continue reading for some of the interesting ways in which scientists and farmers are further reducing the impact of seaweed farming on sea biomes.

Training & Implementation for Best Practices

"Any line dangling in the ocean can pose an entanglement threat to marine life—whether it’s a mooring line for a family’s boat or the buoy line of a fisher’s crab pot. In contrast, the lines used in seaweed aquaculture are fixed structures that are anchored securely to the ocean floor with heavy weights so that they remain taut under tension. Studies suggest that maintaining tight lines may help prevent entanglements, and this is already a standard best practice in seaweed farming.1, 2, 3, 4, 5

Additionally, before receiving approval to begin operating at a specific site, a seaweed farm must conduct an environmental impact study and develop a comprehensive management plan to ensure minimal effect on the surrounding waters, flora, and fauna.1, 3, 4, 6, 7, 8, 9, 10 Of particular importance in minimizing interactions with wildlife is proper siting to avoid their migration routes, as well as their breeding and feeding grounds.1, 6, 7, 8 Due to climate change, some of these locations have been shifting over the years, so ongoing monitoring and reporting is crucial in mitigating potential encounters over the long term.8" - World Wildlife: Seaweed Farming Avoiding the Potential Risk of Entanglement 

"These best practices, studies, and management plans help ensure that seaweed farming continues to develop and operate in a responsible manner as a sustainable industry, while serving as a steward of the ocean and contributing to vital global solutions.

The seaweed industry is exploring strategies to help ensure continued safe operations. For example, WWF is partnering with University of New Hampshire researchers to develop a low-cost sensor that can rapidly alert a seaweed farmer to an entanglement event, thereby decreasing injuries and increasing the likelihood of survival. Another WWF research partnership is exploring the use of composite rods that bend and break if a large marine mammal encounters them, preventing entanglement.11

These endeavors, and other research projects, can help prevent possible future entanglement events. For instance, one study indicates that using red and orange lines increases their visibility for whales, so that encounters can easily be averted.11, 12 Other opportunities exist with infrastructure modifications, such as fewer vertical lines, shorter lines, stiffer lines, weak-link lines, breakaway lines, and recently developed bio-based lines, which can all potentially contribute to lower risks to marine wildlife, as well as to the marine environment in general." - World Wildlife: Seaweed Farming Avoiding the Potential Risk of Entanglement 

Marine Spatial Planning

Marine spatial planning can help farmers identify locations with higher nutrient content, lower oxygen levels, and lower biodiversity so that farms can have a greater positive impact, making them less likely to cause ecological decline. Other considerations such as avoiding turtle or marine mammal migration routes could further reduce accidental wildlife deaths.

Using Local Species

Native species can be a great way to preserve and enjoy cultural and ethnic dishes. These are not only excellent for general health and nutrition, but also support local biodiversity, rather than threaten it as invasive species often do.

Projects & Programs

International

Africa 

Madagascar

Senegal

Tanzania

Tunisia

Asia

China

Malaysia

Philippines

Thailand

Europe

France

Norway

Spain

UK

England

Scotland

Oceana

Australia

New Caledonia

South America

Chile

Apps & Tools

Resources

Europe

Denmark

North America

USA

Organizations

International

Africa

Madagascar

Europe

UK

Scotland

North America

USA

Oceana

New Caledonia

Legalities & Permitting

North America

USA

Grants & Funding


North America

USA

Companies

Africa

Madagascar

Tanzania

Asia

Israel

Philippines

Europe

UK

Scotland

North America

USA

Maine

Oceana

Australia