How do seabirds interact with fisheries and aquaculture? AMARYPESCA project offers new insights on the effects of these activities and the role of RAMPE in the conservation of seabirds

What does RAMPE mean?

RAMPE is the Spanish acronym of the Red de Áreas Marinas Protegidas de España (Spanish network of marine protected areas; Ley 41/2010, del 29 de diciembre, de protección del medio marino). The RAMPE contains the marine protected areas in Spain and its main objective is to ensure the protection, conservation and recovery of the Spanish natural heritage and marine biodiversity. The areas in the RAMPE are subject to different categories of protection: marine protected areas, special areas of conservation, special protection areas for birds, sites of community importance and marine reserves, among others (Figure 1). However, many of these categories do not have a specific management plan that considers the interactions of seabirds with fisheries and aquaculture.

What is the main objective of the AMARYPESCA project?

“AMARYPESCA: Seabirds as a tool to improve the management of fisheries and aquaculture in the context of a sustainable RAMPE” is a project developed by our team, the Seabird Ecology Lab, from the Biology Faculty and the Institute for Research on Biodiversity (IRBio) from the University of Barcelona, together with the Asociación de Naturalistas del Sureste (ANSE), also with the collaboration of the Spanish Institute of Oceanography (IEO).

During this project, we have investigated the role of the RAMPE in the conservation of seabirds in the Spain’s east coast and the Canary Islands, considering how, where and when they interact with fishing vessels and fish farms.

AMARYPESCA, in the framework of the 2019 call of the Pleamar Program, has the support of Fundación Biodiversidad from the Ministry for the Ecological Transition and the Demographic Challenge, and is co-financed by the European Maritime and Fisheries Fund (EMFF).

How do we study the movement of seabirds? And their interactions with fisheries and aquaculture?

To address the movement of seabirds and their interactions with fishing vessels and fish farms, we have tracked several populations from different species (you can see which ones in the publication entitled “Marine protected areas and the conservation of seabirds. Data collection”, in this webpage) and used different methodologies.

On one hand, remote tracking devices are extremely useful to study the movements and distribution of seabirds (among other animals), because they register the animal’s location every few minutes, allowing us to study how they use the RAMPE and the fish farms, and how they interact with fishing vessels. For this purpose, we made a big effort of seabird monitoring in 2020, especially during spring and summer, when several species incubate their eggs and rear their chicks. Moreover, with the collaboration of other research groups and through other projects, we have gathered tracking data of other seabird populations dating back to 2011, to broaden the scope of the analyses performed in this project.

On the other hand, the development of a novel algorithm that uses 1) tracking data from the vessel monitoring system (VMS), as well as tracking data from GPS devices carried by fishing vessels from collaborator fishermen, and 2) tracking data from seabirds equipped with GPS devices, allowed us to detect situations in which a bird is interacting with a vessel (bird and vessel are separated by maximum 1.5 km, the interaction lasts longer than 10 min while the bird is flying at a low speed, indicating that it is probably feeding). With this newly developed methodology, we have obtained detailed information regarding when, where and for how long do seabirds interact with fishing vessels.

With regards to aquaculture, we obtained the location and size of the fish farms in Spain’s east coast, to determine when a seabird equipped with a GPS tracking device goes there. We also conducted surveys to the fish farm workers to identify which seabird species (other than those equipped with GPS devices) are attending the farms.

Results and management suggestions for the RAMPE and human activities at sea

After a profound analysis of the overlap between the RAMPE and the distribution of seabirds along ten years, we see that most areas that seabirds use for foraging are located within the RAMPE, at least partially (Figure 2 shows an example with one of the studied species, the Scopoli's shearwater). However, in other cases the foraging areas were much larger than the areas protected by the RAMPE (Figures 3 and 4, showing the distribution of the Bulwer’s petrel and the Cory’s shearwater) and we also identified two non-protected areas that are very important for some of the seabird populations studied: Golfo de Mazarrón (Figure 5, showing the distribution of the European storm petrel) and the coasts of the Barcelona province (Figure 6, with the distribution of the Balearic shearwater). 

Regarding the interactions between seabirds and fisheries, we detected interactions mainly with the trawl and purse-seine fleets, which are the most abundant and provide food for seabirds through fishery discards at predictable times every day. For Scopoli’s and Cory’s shearwaters, as well as for European shags, most of the interactions with fishing vessels occur within the RAMPE, particularly with trawlers, purse seiners and artisanal vessels, which operate along the coastline (see Figure 7 for an example of interactions between Scopoli’s shearwaters and different fishing fleets). In other cases, such as the Balearic shearwater (critically endangered according to UICN), only a small proportion of the interactions with fishing vessels occur within the RAMPE (Figure 8).

Regarding the interactions between seabirds and fish farms, the data obtained from seabirds equipped with GPS tracking devices, together with the surveys conducted with fish farm workers, indicate that two species are regularly present in these farms: yellow-legged gulls and European shags.

Figure 7. Seabird – fishing vessel interactions detected between Scopoli's shearwaters and the trawl (top left), purse seine (top right) and pelagic longline (bottom) fleets in Spain’s east coast and the Balearic Islands (data holder: Seabird Ecology Lab for the Scopoli’s shearwater data, Secretaría General de Pesca and IEO for the VMS data). Circle size indicates the interaction duration. Green lines show the RAMPE. See that most interactions with trawlers and purse seiners occur inside the RAMPE, while many interactions with pelagic longliners happen outside of it. Arrastre: trawl, cerco: purse-seine, palagre de superficie: pelagic longline.

Considering all these previous findings, we show that the RAMPE covers the waters surrounding most breeding colonies of the studied seabird populations, which could be particularly relevant for species that make short foraging trips during the breeding period, such as the Audouin’s gull, yellow-legged gull and European shag. However, most RAMPE areas lack management measures aimed at protecting seabirds in the marine environment, and therefore there is a need to design and implement management plans that regulate human activities carried out in these areas. Such measures could include recreational fishing restrictions, the requirement to install mitigation measures to reduce bycatch of seabirds (tori lines and night setting, among others, see Cortés and González‐Solís 2018), and even the temporary closure of certain fishing areas during the breeding period of some seabird species. Management measures like these could have a positive effect on the conservation of Spanish seabird populations, especially those that interact with fishing vessels and fish farms mainly inside the RAMPE.

In the case of those seabirds that make long foraging trips and show large distributions in pelagic zones, such as the Bulwer’s petrels (Figure 4) and the Cory’s shearwaters (Figure 5) studied here, the proportion of RAMPE overlapping with their distribution is very small (the RAMPE mainly covers coastal areas). In such cases, fisheries management and mitigation measures to reduce seabird bycatch risks could be much more efficient than the establishment of new coastal protected areas.

With regards to the interactions specifically between coastal seabirds and fish farms, mitigation measures that reduce the attendance to the farms should be considered, otherwise these interactions could create a non-desired dependency on food available for seabirds in fish farms. Moreover, in the case of overabundant birds like the yellow-legged gull, the use of fish farms as a food source could contribute to increase their population numbers, abundant since the 80’s and that competes with other seabirds of smaller size.

Last but not least, given that we identified two areas highly used by seabirds and with a high risk of interaction with fisheries, but not protected, there is a need for the identification of new important areas for the conservation of seabirds in Spain, based on tracking data such as those gathered through this project.

All maps were developed by Virginia Morera.