Seabird Ecology Lab

Movement ecology, conservation biology, symbiotic interactions and marine environmental chemistry in seabirds

Use of marine protected areas by Audouin’s gulls during their breeding period and migration

20th November 2020

The Seabird Ecology Lab (Faculty of Biology from Universitat de Barcelona and the Institute for Research on Biodiversity-IRBio) is developing the project “GAUDIN: La gaviota de Audouin como instrumento para la mejora de la gestión de la RAMPE en el Levante español” (Audouin’s gull as a tool to improve the management of RAMPE in the Spanish east coast). This project has the support of Fundación Biodiversidad from the Ministry for the Ecological Transition and the Demographic challenge, with the collaboration of the Asociación de Naturalistas del Sureste (ANSE) and the Spanish Institute of Oceanography (IEO).

The main objectives of GAUDIN project are 1) to address the role of the Spanish network of marine protected areas (Spanish acronym: RAMPE) in the conservation of an endangered and endemic species to the Mediterranean Sea, the Audouin’s gull (Ichtyaetus audouinii), and 2) to investigate the interactions between Audouin’s gulls and fishing vessels, in order to improve the management of RAMPE and fisheries. These objectives align with LIFE INTEMARES actions, which aim for an efficient management of marine areas from Natura 2000 with the collaboration of the sectors involved and research as main tools for decision making.

To achieve these objectives, we equipped 18 Audouin’s gulls with GPS/GSM tracking devices (Global Positioning System/Global System for Mobile communications). We placed the devices on both adult individuals (during incubation) and chicks (during chick rearing), between May and July from 2020, in the Regional Park of Salinas y Arenales de San Pedro del Pinatar (Murcia). These devices can register a location every minute and send this information via the mobile communications network, which will allow us to investigate the movements of Audouin’s gulls with a very high temporal and spatial resolution.

Audouin’s gull equipped with a GPS/GSM tracking device on the back. San Pedro del Pinatar, Murcia. Credit: Raquel Castillo Contreras.
Deployment of a GPS/GSM tracking device through a harness. San Pedro del Pinatar, Murcia. Credit: Raquel Castillo Contreras.
Releasing an Audouin’s gull equipped with a GPS/GSM tracking device. San Pedro del Pinatar, Murcia. Credit: Raquel Castillo Contreras.

Since Audouin’s gull is a migratory species, we have been able to obtain movement data during the breeding period, when they were at their breeding colony in the Spanish east coast, and also during their migration, when in general they left towards African coasts. Currently, there are 10 GPS/GSM tracking devices that continue functioning, six of them placed on adult gulls and four on juveniles. The positions gathered by all of them add up to 1,200,000.

Preliminary results show that, during the breeding period (we considered May and June), most locations registered by the GPS/GSM tracking devices took place ashore (overall: 69.3%; per age class: 69.1% adults, 100% juveniles), while just a third of them (30.7%; per age class: 30.9% adults, 0% juveniles) were at sea. Regarding the overlap between Audouin’s gull movements and the RAMPE, only a third (31.6%) of the total locations at sea -all belonging to adult gulls- took place within RAMPE spaces. Since juveniles were equipped with tracking devices by the end of June and they stayed in the breeding colony until migrating, all their positions were ashore and they did not use the RAMPE. All the locations registered during the breeding period and their overlap with the RAMPE are depicted in the following map.

Locations and overlap with RAMPE spaces of Audouin’s gulls equipped with GPS/GSM tracking devices in the breeding colony of San Pedro del Pinatar. Period: from the beginning of May to the end of June of 2020.

With regards to their migration, most adult gulls equipped with GPS/GSM tracking devices left the breeding grounds between late June and late July, while juvenile gulls migrated -in general- after their parents, from mid-July to early August. Some gulls (both adults and juveniles) travelled long distances in a relatively short amount of time, while others made a few stops while migrating. Moreover, some of them are still on the move. Audouin’s gulls have travelled between 400 and 3,400 km in 1 to 40 days, except for one adult gull that did not leave the Iberian Peninsula.

During their migration (here we considered July and August), the percentage of locations ashore registered by the tracking devices varied between age classes (overall: 57.3%; per age class: 46.6% adults, 67.1% juveniles), being slightly lower (in adults) or higher (in juveniles) than the percentage of positions at sea (overall: 42.7%; per age class: 53.4% adults, 32.9% juveniles). As for the overlap with the RAMPE, the use of these spaces by Audouin’s gulls was scarce: only 9.7% of at sea locations occurred within these spaces (per age class: 8,7% adults, 11.2% juveniles).

Locations of Audouin’s gulls equipped with GPS/GSM tracking devices during their migration (from early July-early September, depending on the individual, to late October 2020).

With regards to the wintering areas, four out of six adult gulls migrated towards the Atlantic coast of Morocco, Western Sahara and Mauritania, while the other two stayed in the Alborán Sea. Overall, the most frequent wintering and migration areas were Dahkla (Río de Oro Peninsula, Western Sahara) and Nouadhibou (Cabo Blanco Peninsula, on the border between Western Sahara and Mauritania). As for the two adult gulls that stayed in the Alboran Sea, they are currently in Moroccan coasts (provinces of Driouch and Nador) and Spanish coasts (Almería), and the latter did not migrate. Regarding the juvenile gulls (five of them migrated, four still have functioning tracking devices), in general they migrated further away from the breeding colony than adult gulls, given that they have already reached Western Sahara, Mauritania and Senegal. The wintering and migration areas more used by juveniles were Nouadhibou (Western Sahara/Mauritania), Nuakchot (Mauritania) and Dakar (Peninsula of Cape Verde, Senegal).

Click on the following map to explore all the migratory routes and wintering areas of Audouin's gulls.

Instamaps showing the movements of Audouin’s gulls equipped with GPS/GSM tracking devices during their migration (from early July-early September, depending on the individual, to late October 2020). Each individual is displayed in a different colour (adults in blue and green colours, juveniles in yellow colours).

Despite we need to perform detailed spatial and temporal analyses, as well as take interactions with fisheries into account, these preliminary results show that RAMPE spaces are more used by adult Audouin’s gulls, especially during the breeding period. The lower use of RAMPE by both age classes during migration is related to the migratory behaviour of the species, given that they travel long distances outside national territory.

Furthermore, the wintering areas and migratory routes used up until this moment by Audouin’s gulls in general agree with areas previously described as important for their migration (https://tinyurl.com/yy5j5ul7). The Canary Current, characterised by cold and rich waters, has a high productivity in the Atlantic coast of northern Africa, which allows Audouin’s gulls to obtain food (mainly epipelagic fishes) both from natural and anthropogenic sources (fishery discards from fishing vessels and in ports). Agreeing with this, there are industrial and artisanal fishing fleets in Dakhla, Nouadhibou and Dakar, which are probably exploited by Audouin’s gulls. Moreover, the single Audouin’s gull that stayed in Spain frequently visits Adra’s port (Almería), other ports in the area and croplands, which suggest that this non-migratory individual also utilises resources derived from human activities.

These preliminary results contribute with relevant data to the knowledge on movements and use of RAMPE by Audouin’s gulls in the Spanish east coast, as well as on their wintering areas and migratory routes in the Atlantic and Mediterranean coasts of northern Africa. These results, together with the analysis of their interactions with fisheries, will help in achieving the objectives of the GAUDIN project for a better management of RAMPE and fishing activities.


Marine protected areas and the conservation of seabirds

Data collection

26th October 2020

We have already carried out the field work and data collection of the project “AMARYPESCA: Las aves marinas como instrumento para la mejora de la gestión pesquera y acuícola en el contexto de una RAMPE sostenible” (seabirds as a tool to improve the management of fisheries and aquaculture in the context of a sustainable RAMPE). This project has two objectives: 1) determining the role of the Spanish network of marine protected areas (Spanish acronym: RAMPE) in the conservation of seabirds, and 2) addressing the interactions between seabirds and both fishing and aquaculture activities, in order to improve the management of RAMPE and of the human activities at sea. These objectives align with LIFE INTEMARES actions, which aim for an efficient management of marine areas from Natura 2000 with the collaboration of the sectors involved and research as main tools for decision making.

AMARYPESCA project is part of the 2019 call of the Pleamar programme, which has the support of Fundación Biodiversidad (biodiversity foundation) from the Ministry for the Ecological Transition and the Demographic challenge and is co-funded by the European Maritime and Fisheries Fund (EMFF). The project is being developed by the Seabird Ecology Lab, from the Faculty of Biology from Universitat de Barcelona and the Institute for Research on Biodiversity (IRBio), and its partner organisation, the Asociación de Naturalistas del Sureste (ANSE), with the collaboration of the Spanish Institute of Oceanography (IEO).

Most of the fieldwork of AMARYPESCA has been carried out by the Seabird Ecology Lab, in close collaboration with ANSE, from June to September of 2020. The field campaigns were conducted by different teams in several autonomous communities: Balearic Islands, Valencian Community, Region of Murcia, Andalusia and Canary Islands (Figure 1). We have obtained abundant movement data during these campaigns, which will allow us to perform the analyses needed to achieve the objectives of AMARYPESCA.

Figure 1. Study areas. From North to South: Menorca and Illa de l’Aire (Balearic Islands), Illes Columbretes (Valencian Community), San Pedro del Pinatar, Isla Grosa and Isla de las Palomas (Region of Murcia), Isla de Terreros (Andalusia), Montaña Clara and Veneguera (Canary Islands Canarias).

During the field campaigns we have worked with different seabird species: Cory’s shearwater (Calonectris borealis), Scopoli’s shearwater (Calonectris diomedea), European storm petrel (Hydrobates pelagicus and Hydrobates p. melitensis) and Bulwer’s petrel (Bulweria bulwerii) (Figures 2, 3 and 4, respectively). Moreover, we are still collecting movement data from European shags (Gulosus aristotelis) and yellow-legged gulls (Larus michahellis) equipped with GPS/GSM transmitters (Figures 5 and 6) between January and April of the present year in the Balearic Islands and Murcia. Preliminary results on the movement and use of different habitats by these species can be found in a post below.

Figure 2. Cory’s shearwater (Calonectris borealis). Veneguera, Gran Canaria. Picture credit: Raül Ramos.
Figure 3. European storm petrel (Hydrobates pelagicus). San Pedro del Pinatar, Murcia. Picture credit: Ángel Sallent.
Figure 4. Bulwer’s petrel (Bulweria bulwerii). Montaña Clara, Lanzarote. Picture credit: Raül Ramos.
Figure 5. European shag (Gulosus aristotelis) equipped with a GPS/GSM transmitter. Illa de l’Aire, Menorca. Picture credit: ANSE.
Figure 6. Yellow-legged gull (Larus michahellis) equipped with a GPS/GSM transmitter. San Pedro del Pinatar, Murcia. Picture credit: Antonio Zamora.

We have used different tracking devices to assess the use of RAMPE by seabirds and to investigate the interactions among seabirds, fishing vessels and fish farms. Global Positioning System (GPS) tracking devices can provide the location of tagged individuals with a very high temporal and spatial resolution. Some of these devices can also measure the acceleration of the animal and detect direct interactions with radars from fishing vessels. If the tracking devices use Global System for Mobile communications (GSM) technology, we can receive all data via the mobile communications network, virtually in real-time. Otherwise, we need to retrieve the devices after a few days and up to a month after the deployment to obtain the movement data collected by them. Check Figure 7 to see the deployment process of a GPS tracking device on the back of a Scopoli’s shearwater, and Figures 5, 6, 8, 9 and 10 to see several of the devices we used depending on the species behavioural and morphological traits.

In addition to GPS tracking devices, we have also deployed Global Location Sensing (GLS) devices, or light-level geolocators (Figure 11), on a selection of individuals tagged with GPS tracking devices. Geolocators are used to study large-scale migratory movements, but they also measure the conductivity of salt water, providing useful information on whether the animals are in contact with sea water. Thus, we can infer the activity of seabirds based on the wet or dry state of the geolocator: resting on the water (geolocator wet), flying (geolocator dry) or foraging (frequent shifts in wet-dry state).

Figure 7. Deploying a GPS tracking device on the back of a Scopoli’s shearwater. Illes Columbretes, Castellón de la Plana. Picture credit: Jorge Crespo.
Figure 8. GPS tracking device equipped with radar detector deployed on a Cory’s shearwater. Montaña Clara, Lanzarote. Picture credit: Fernando Medrano.
Figure 9. GPS tracking device deployed on a Bulwer’s petrel. Montaña Clara, Lanzarote. Picture credit: Fernando Medrano.
Figure 10. GPS tracking device deployed on a European storm petrel. Isla de las Palomas, Murcia. Picture credit: ANSE.
Figure 11. Geolocator deployed on a Bulwer’s petrel. Montaña Clara, Lanzarote. Picture credit: Raül Ramos.

In summary, we obtained 1004 foraging trips (round trips from the breeding colony) from 290 individuals (all species) during the fieldwork developed from June to September of 2020. Out of the total amount of trips, 244 were obtained during the incubation period and 537 were obtained during the chick rearing period (Figures 12 and 13). Table 1 includes the number individuals tagged and foraging trips per species, breeding colony breeding phase. Foraging movements from all the studied seabirds cover a wide area of the Mediterranean Sea and the Atlantic Ocean, in addition to the coasts belonging to several Spanish autonomous communities and different countries in Africa.

Figure 12. Scopoli’s shearwater incubating the egg. Veneguera, Gran Canaria. Picture credit: Raquel Castillo Contreras.
Figure 13. Scopoli’s shearwater chick. Cala Morell, Menorca. Picture credit: Leia Navarro.
Table 1. Number of individuals and foraging trips per species, autonomous community, breeding colony and breeding phase.

All the movement-related data collected from the different seabirds studied here will allow us to perform a detailed spatio-temporal analysis that will help in characterising the interactions among seabirds, fishing vessels and fish farms, identifying the drivers of these interactions, and determining the most dangerous situations for seabirds. Moreover, these analyses will also enable us to propose measures to improve the management of RAMPE and of human activities at sea, which would ultimately allow a sustainable exploitation of the marine environment that minimises the adverse impact on seabirds.




World Oceans Day

Seabirds and the Network of Marine Protected Areas

8th June 2020

Seas and oceans are one of the most unknown and at the same time most fascinating ecosystems on the planet. However, growing human activities in the marine environment are rapidly accelerating their deterioration. As a result, many countries are increasing the surface of their marine protected areas. In Spain, the figure of Marine Protected Area has existed since 2007 (Law 24/2007 on Natural Heritage and Biodiversity), and in 2010 the Network of Marine Protected Areas was formally created (RAMPE, law 41/2010 on the protection of the marine environment) with the aim of carrying out a coherent management of the marine environment in order to achieve a good environmental status. In 2014, 39 special protection areas for birds from the Natura 2000 Network became part of the RAMPE. Despite this, only around 13% of Spanish waters are currently under some form of protection, and many of them still do not currently have management plans that consider such important aspects as interactions between seabirds and fisheries or aquaculture.

Seabirds are top predators, meaning that they are found in the upper levels of marine trophic networks. This advantageous position makes them sensitive to most alterations in the marine ecosystem, making them sentinel species of the seas and oceans health. In addition, seabirds live at the interface between the marine and terrestrial environments, feeding at sea and returning to land to rest, nest and rear their chicks, allowing us to study them with relative ease. One of the most important information we can get from seabirds is their at-sea distribution, the areas they use to feed and to find food for their chicks. This information, combined with diet and ecotoxicology studies helps us to know the environmental quality of the different marine regions, as well as the health of fishing stocks. The most practical and accurate method for obtaining this information is the deployment of remote tracking (GPS) devices, which can record and transmit their movements at intervals of up to less than a minute through the mobile phone network.

Currently, our research group (Seabird Ecology Group) of the Faculty of Biology and the Institute for Research on Biodiversity (IRBIo) of the Universitat de Barcelona, in collaboration with the Asociación de Naturalistas del Sureste (ANSE), are developing two projects with the support of Fundación Biodiversidad from the Ministry for the Ecological Transition and the Demographic Challenge, and also in collaboration with the Spanish Institute of Oceanography (IEO). The objectives of both projects are linked to the actions of LIFE INTEMARES, which pursue the effective management of marine areas within the Natura 2000 network, with the active participation of the involved sectors and research as main tools for decision making.

The project “AMARYPESCA: Las aves marinas como instrumento para la mejora de la gestión pesquera y acuícola en el contexto de una RAMPE sostenible” (seabirds as a tool to improve the management of fisheries and aquaculture in the context of a sustainable RAMPE)", in the framework of the 2019 call of the Pleamar Program, co-financed by the European Maritime and Fisheries Fund, aims at knowing the role that the current RAMPE plays in the conservation of seabirds, in addition to investigating the interactions between seabirds and fishing and aquaculture activities, in order to improve the management of RAMPE and human activities at sea.

Along the same lines, the project "GAUDIN: La gaviota de Audouin como instrumento para la mejora de la gestión de la RAMPE en el Levante español” (The Audouin's gull as a tool for improving the management of RAMPE in Spain’s east coast”, in the framework of the call for proposals for the conservation of marine biodiversity in Spain 2019 of the Fundación Biodiversidad of the Ministry for Ecological Transition and Demographic Challenge, seeks to know the role of the current RAMPE in the conservation of Audouin's gull (Ichtyaetus audouinii) and characterize the interactions between these birds and fishing vessels.

To achieve these goals, we have placed several GPS devices in seabirds of different species: the European shag (Gulosus aristotelis) and the yellow-legged gull (Larus michahellis) as part of the AMARYPESCA project, and the Audouin's gull as part of the GAUDIN project.

In the following map you can see the trips of all the individuals marked with GPS devices of European shag (orange) in Isla Grosa (Murcia) and Illa de l’Aire (Balearic Islands), and of yellow-legged gull (blue) and Audouin’s gull (yellow) in San Pedro del Pinatar (Murcia), registered from the time of its placement until the end of May.

Of the three species instrumented with GPS to date in the Spain’s east coast, we first worked with the European shag. This seabird, which nests in areas of rocky cliffs, is listed as a vulnerable species in the Spanish Catalog of Threatened Species, as it is threatened by bycatch, overfishing and marine pollution.

The ANSE team, partners in the AMARYPESCA project, carried out the fieldwork in January and February, deploying GPS devices in a total of eight adult birds, mostly breeders, from Isla Grosa (Murcia) and Illa de l’Aire (Balearic Islands).

European Shag (Gulosus aristotelis) equipped with a GPS/GSM device. Picture credit: ANSE.

The spatial ecology of this species is still quite unknown, and we hope that the results we are obtaining with this project can contribute to its knowledge. On the map above you can see how Isla Grosa’s European shags often move north, approaching and possibly interacting with fish farms. Instead, we can observe that the individuals of Illa de l’Aire move near the coasts of the islet, as well as Menorca and Mallorca. Here you can see in detail the latest movements of individuals equipped with GPS devices.

Next, we worked with the yellow-legged gull, a seabird with mostly coastal habits, with great foraging strategy adaptability. Thanks to these generalist attributes, it has adapted in an extraordinary way to take advantage of trophic resources derived from human activity, such as the food available in landfills or from fisheries discards. This association with anthropogenic habitats has made their populations grow exponentially throughout its range, and it has very abundant breeding populations throughout the coast. ANSE staff deployed 17 GPS devices in adult breeding individuals from San Pedro del Pinatar (Murcia).

Yellow-legged gull (Larus michahellis) equipped with a GPS device. Picture credit: Antonio Zamora.

The first results obtained support this change in diet towards anthropogenic food subsidies, mainly of terrestrial origin (landfills, waste treatment centers, crop fields and irrigation ponds ...). In addition, the trips they make at sea seem to be linked to possible interactions with fisheries discards and fish farms. Here you can see the latest movements of individuals equipped with GPS.

The last species we have worked with is Audouin's gull. This species is endemic to the Mediterranean and cataloged as vulnerable in the Spanish Catalog of Threatened Species. The Spain’s east coast is home to the most important breeding populations of the entire species. Its main current threats are bycatch, dependence on fisheries discards and marine pollution.

A field team from ANSE and the Universitat de Barcelona deployed seven GPS devices in breeding adult Audouin’s gulls from San Pedro del Pinatar (Murcia).

Deploying a GPS device (using a harness) on an Audouin's gull (Ichtyaetus audouinii). Picture credit: Raquel Castillo Contreras.

The results obtained so far demonstrate that this species also makes extensive use of land resources of anthropogenic origin, including those available in urbanized areas and cultivated fields. However, our preliminary results show that part of the population specializes in feeding in marine habitats, often taking advantage of fishing discards. Here you can see the latest movements of Audouin's gulls equipped with GPS.

Finally, it is worth highlighting the importance of these results, albeit still preliminary, towards the achievement of the objectives of both projects. A better understanding of the spatial ecology of seabirds and their interactions with fisheries and fish farms, adding to the equation the limits of the current RAMPE, will allow us to understand the role that the current RAMPE has in the conservation of seabirds. This will help improve the management of RAMPE and of fishing and aquaculture production activities so that human activities and marine birds can coexist.