Small cetacean mortality as derived from stranding schemes: the harbour porpoise case in the northeast Atlantic.
Peltier, H, Czeck, R., Dabin, W., Daniel, P., Deaville, R., Haelters, J., Ijsseldijk, L.L., Jensen, L.F., Jepson, P.D., Keijl, G., Olsen., M.T., Siebert, U., Van Canneyt, O., Ridoux, V.
International Whaling Commission
In this work, we propose (1) to identify likely mortality areas at sea inferred from strandings in the eastern North Atlantic, from the Bay of Biscay to the English Channel and the North Sea, (2) to estimate mortality of harbour porpoises in this large area, with a focus (3) on mortality due to fishery activities on harbour porpoise population in the Bay of Biscay and the English Channel.
This work provided relevant information on the distribution of harbour porpoise mortality across the North Sea, the Channel and the Bay of Biscay over a period of 25 years. The detection of a southward shift in porpoise mortality areas in the northern North Sea, the Channel and the southern Bay of Biscay was consistent with the outcomes of the SCANS I-to-III dedicated surveys regarding changes in porpoise distribution in the north-east Atlantic.
This work also suggested that from 2012 onwards, a yearly average of 1300 harbour porpoises died in fisheries interactions in the English Channel and the Bay of Biscay. Following recent abundance estimations in these areas, such a mortality level could be unsustainable for porpoise populations in the medium or long term.