The main objective of this project is to promote the voluntary implementation of measures to mitigate the accidental fishing of birds such as the Balearic, Mediterranean and Cory’s shearwater, and the Audouin’s gull. The aim is to contribute to the sustainability and efficiency of the longline fishery, in particular in the Important Bird Areas of the Marine Platform of the Ebro-Columbretes delta, the Empordà Sea and the Site of Community Importance of the Columbretes Islands. Likewise, it also seeks to improve the estimates of bycatches, determine the interannual variability of the areas and periods where the interaction between birds and longlines is more intense and continue testing bycatch mitigation measures.

The main objective of this project is to promote the voluntary implementation of measures to mitigate the accidental fishing of birds such as the Balearic, Mediterranean and Cory’s shearwater, and the Audouin’s gull. The aim is to contribute to the sustainability and efficiency of the longline fishery, in particular in the Important Bird Areas of the Marine Platform of the Ebro-Columbretes delta, the Empordà Sea and the Site of Community Importance of the Columbretes Islands. Likewise, it also seeks to improve the estimates of bycatches, determine the interannual variability of the areas and periods where the interaction between birds and longlines is more intense and continue testing bycatch mitigation measures.

The current rates of bycatch of birds are not sustainable and are causing the decline of the 3 species of shearwaters endemic to the Mediterranean, which could even lead to the extinction of the Balearic shearwater in the medium term. Therefore, this proposal focuses on promoting the implementation of bycatch mitigation measures. To achieve these objectives, the following action plan has been drawn up:

• Obtaining data on the distribution, abundance and movements of nesting specimens of Cory’s shearwater in a breeding colony in the Balearic Islands by tagging with GPS devices. Identification of feeding trips that show contact with fishing vessels by marking with portable cameras and checking the diving ability of Cory’s shearwaters.
• Obtaining a detailed map of the fishing effort of the longline fleet of the eastern Mediterranean in space and time. Analysis of the spatiotemporal overlap between birds and longliners based on the information collected.
• Observer embarkation on about 4 sailings per month. Record of the route of longliners and the position of their fishing grounds. Bird censuses. Information on longline and longline characteristics and estimates of seabird bycatch rates by species, sex, age, molting status and physical condition.
• Analysis of the variables that have the greatest influence on the attraction and capture of birds
• Sampling and analysis of Cory’s shearwater feathers. Assignment to home colonies by applying a discriminant function model
• Hiring of a bottom longliner to apply different mitigation measures (night draft, addition of weights, artificial baits and scarecrow line). Longline sinking time check to assess the accessibility of birds to bait.
• Development of a manual of good longline fishing practices that informs and provides instructions on the implementation of mitigation measures that reduce bird catches