First bycatch data collected by Seabird Task Force observers in Spain

According to previous information, May and June is the most dangerous time of the year for seabird bycatch in the Western Mediterranean and observer effort has been intensified. The bycatch of the 3 Cory’s shearwaters (Calonectris diomedea) has occurred during three monitored fishing operations. Cory’s shearwater was the main species attending at demersal long-liners during the line setting and hauling.

Cory's shearwater Calonectris diomedea accidentaly captured on a pelagic long-liner
Cory’s shearwater Calonectris diomedea accidentaly captured on a demersal long-liner. Photo: Albert Cama

The analyses of the corpses indicated that some dead birds could be active breeders, showing breeding patch. The internal analysis of one bird indicated that it was an adult female.

See breeding patch on a Cory's shearwater Calonectris diomedea
See breeding patch on a Cory’s shearwater Calonectris diomedea Photo: Albert Cama

In addition to the data collected by SEO/BirdLife observers, fishermen reported the bycatch of other seabirds during the last weeks, including another Cory’s shearwater, 2 Atlantic gannets (Morus bassanus) and up to 40 unidentified shearwaters, including a massive event of 20-30 birds. We should mention that the skipper aborted the line setting due to the big amount of seabirds attacking to bait. Two Mediterranean European shags (Phalacrocorax aristotelis desmarestii) were accidentaly captured on cuttlefish pots. Additionally, 2 Cory’s shearwaters, 2 Yelkouan shearwaters (Puffinus yelkouan) and 5 Balearic shearwaters (Puffinus mauretanicus) were found death in one beach in Tarragona, they did not showed the presence of hooks, but some injuries near the mouth, indicating Long-line bycatch.

We wish to thank the collaboration of fishermen by allowing observers on board and reporting data.

Cory's shearwater Calonectris diomedea eating discarded fish from a demersal Long-liner
Cory’s shearwater Calonectris diomedea eating discarded fish. This has been the most abbundant species attending demersal long-liners. Photo: Albert Cama
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5 thoughts on “First bycatch data collected by Seabird Task Force observers in Spain

Such sad tales but it is something which needs the broad scale attention of the general public and your work will only assist in getting the bigger picture of seabird bycatch across to the masses. I applaud you all.

Best Wishes

Tony Powell


Thank you for your support, Tony!


Thanks for sharing. Brood patches are also found in non-breeding petrels and shearwaters visiting colonies. This feature should be used with some caution. Regards Miguel


Tony many thanks for the support and Miguel, also thanks for your comment about the breeding patch. I will take into account


Great to see some discussion happening here! Please feel free to contribute your thoughts and ideas. Thanks for the messages of support, we agree that this is an important issue that can be worked on collaboratively with fishermen to find solutions!


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