Bycatches of common guillemot (Uria aalge) in the Baltic Sea gillnet fishery

Bycatch of common guillemots (Uria aalge) appears to be the single most serious threat to the population, and the proportion ofrecoveries of ringed birds in fishing gear, compared with other finding circumstances, has significantly increased during a 28 yearperiod (P<0.01). Out of 1952 ringed common guillemots reported found between 1972 and 1999 in the Baltic Sea, 980 (50.2%)were caught in fishing gear. The bycatch in set gillnets for cod (Gadus morhua) constituted 22.3%, drift gillnets for salmon (Salmosalar) 65.5%, and other fishing gear 12.2%. The proportion of recoveries in cod gillnets has significantly increased during the studyperiod (P<0.05), while no clear trend was observed in the recoveries in salmon gillnets. The Swedish fishing effort follows a similarpattern for cod but has decreased for salmon. The observed increased use of cod gillnets in the Baltic Sea may have contributed tothe observed decrease in adult survival rate, and we provide two different estimates suggesting that significant proportions of theguillemot population are caught annually in the Baltic Sea gillnet fishery. We suggest several available techniques to reduce bycatchin the Baltic Sea fishery

Henrik Osterblom, Thord Fransson, Olof Olsson, Biological Conservation 105 (2002) 309-319