Study on mitigation measures to minimise seabird bycatch in gillnet fisheries
The incidental capture of non-target marine animals in fishing gear, such as seabirds, cetaceans, elasmobranchs, and turtles, is commonly referred to as ‘incidental bycatch’. Seabird bycatch in bottom set gillnet fisheries (GNS) is known to be a major conservation issue both globally and within Europe; an estimated 76,000 birds are caught annually in the Baltic Sea alone (Žydelis et al. 2013). Diving seabirds, such as seaducks, auks, divers, grebes and cormorants are particularly susceptible to capture in this gear. Gillnets, made of thin nylon twine, are essentially invisible under water, and... diving birds are presumably not able to perceive the net whilst foraging at depth, becoming entangled and drowning. This particular fishing gear is used extensively across Europe, with both small and large-scale fleets operating in EU member states’ waters. A lack of systematic data collection across most of Europe on gillnet fishing effort (particularly small-scale vessels) and on bycatch has meant that little information is available to assess which countries, fleets and sites are particularly at risk of causing seabird bycatch. Despite the general lack of information, some studies on seabird bycatch in gillnets have been conducted over the past few decades and these indicate that specific regions of Europe are ‘hotspots’ for bycatch in this gear. The Baltic Sea, with its internationally important populations of wintering seaducks, such as long-tailed duck, velvet scoter, common and steller’s eider is one such ‘hotspot’. In addition to the lack of fine scale information on gillnet fisheries, one of the most significant challenges for managing bycatch in this gear is the lack of technical solutions. For other fishing gears, such as longlines and trawls, technical solutions have already been developed and successfully implemented in a number of fisheries (largely outside of the European Union), resulting in substantial reductions (or even the elimination) of seabird bycatch.