Decreasing but still high: bycatch of seabirds in gillnet fisheries along the German Baltic coast

The magnitude and temporal trends of seabird bycatch in coastal set net fisheries in the eastern part of the German Baltic Sea were studied, based on (i) a survey of 4% of the total fishery in the period 2006–2009, and (ii) results from bycatch monitoring in a part of this region covering a period of 20 years. Bird carcasses were collected and information on fishing effort obtained from fishermen using interviews and on-board observations on selected trips. Bycatch of seabirds occurred with all types of fishing gear and metiers studied, with highest bycatch rates in coastal lagoons. The minimum estimate of total bycatch in nets set by 440 commercial fishermen was found to be 17 551 (range 14 905–20 533) birds annually between November and May. Bycatch in set nets and on longlines in summer was much lower. Bycatch rates were found to depend either directly on bird abundance as shown for the long-tailed duck (Clangula hyemalis) or on predictors of abundance such as water depth and location. Bycatch in the Pomeranian Bay has decreased over 20 years due to the severe decline of seaducks, particularly of long-tailed ducks, which were most frequently bycaught. The estimated individual bycatch risk has also decreased in long-tailed ducks but the current monthly losses of 0.81% may still indicate a potential threat for this species. Bycatch monitoring based on carcass collections and interviews proved to be feasible over a 20-year period although the results contain some underreporting. Based on the results specific measures are recommended to reduce bycatch risk in the German coastal fisheries using targeted effort reductions and replacement of set nets with alternative gear. Copyright © 2012 John Wiley & Sons, Ltd.