Accidental by-catch -which affects around 5,000 birds stuck in longlines every year- is the most severe effect on marine birds by the fishing activity in the Mediterranean. The exploitation of fishing resources is threatening more and more the future of many marine birds with regression populations, such as Cory's shearwater or the Balearic shearwater.

Studying the interaction between marine birds and fishing activities in the peninsular Levant in Spain is the objective of a project coordinated by Jacob González-Solís, lecturer from the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona, and funded by Fundación Biodiversidad. Other partner entities of the new project are the Spanish Institute of Oceanography (IEO) and Asociación de Naturalistas del Sureste (ANSE).

From Andalusia coasts to Catalonia and the Balearic Islands

Marine birds, which are key elements in the trophic pyramid of the oceanic ecosystems, are also bioindicators of the environmental quality of the marine environment. As adults, they can fly hundreds of kilometres seeking food, so their biological activity is overlapped with the threats from fishing activities (accidental by-catches, decline of the main fishing areas, etc.).

The new project, led by the experts from UB-IRBIO, will assess the most critical factors of the interaction in space and time between marine birds and fishing fleets ─activity overlap, predictive factors, etc.─ over the Levant coast, from Andalusia to Catalonia and the Balearic Islands. This initiative will specially help them to see the efficiency of the Spanish Network of Marine Protected Areas (RAMPE), which covers several protection figures to preserve the marine natural heritage. Its aim is to improve the protection of marine birds in the peninsular coast.

Marine birds and fishing boats: shared routes in the Mediterranean

The routes, distribution and behaviour of the marine birds can be studied in detail thanks to global positioning systems (GPS). This project will combine the information from the global positioning systems of the Spanish fishing fleet with the database of the UB-IRBio team on the habitat and ecology of Cory's shearwater (Calonectris diomedea), the Balearic shearwater (Puffinus mauretanicus), the Yelkouan shearwater (Puffinus yelkouan), Audouin's gull (Larus audouinii), and the Yellow-legged gull (L michahellis). They will also use the GPS and GLS technology in 2018 to study the movements of the Cory's shearwater from their breeding colonies -in particular, the Balearic Islands, Castelló, Murcia and Almería- to the main feeding areas during their breeding season, a key period in the species' annual cycle.

According to Jacob González-Solís, from the Department of Evolutionary Biology, Ecology and Environmental Sciences of the UB and IRBio, "knowing in detail the rhythm of the activities of these birds will help us shaping the profile of their natural habitat -feeding areas, etc.- and to find the most sensitive areas for the preservation of these species." In this context, he continues, "the new project will be determining to study the kind and degree of interaction between pelagic birds and fishing fleet, and to identify the main factors that modulate this interrelation."

The experts Raül Ramos, Leia Navarro and José Manuel de los Reyes (UB-IRBIO) also take part in the project, supported by Fundación Biodiversidad and the Spanish Ministry of Agriculture and Fisheries, Food and Environment, through the Pleamar Program of the European Maritime and Fisheries Fudn (FEMP). The initiative has the collaboration of other experts from SEO/BirdLife, BirdLife International, the University of Oxford (United Kingdom), the Center of Functional and Evolutionary Ecology of Montpellier (CEFE-CNRS, France) and the Directorate-General of Environment and Environmental Evaluation of the Valencian Government.