Interactions between seabirds and deep‐water hake trawl gear: an assessment of impacts in South African waters

摘要: Many seabirds are killed or injured by fishing gear, contributing to the high proportion of threatened seabirds. This study estimates impact South African deep-water hake Merluccius spp. trawl fishery on At least 30 birds were in 190 h dedicated observations warps during 2004 and 2005. Most when their wings entangled around warp they dragged under force water passing over warp. Albatrosses most frequently: shy albatrosses Thalassarche cauta (43% all killed) black-browed melanophrys (37%), with smaller numbers white-chinned petrels Procellaria aequinoctialis (10%), Cape gannets Morus capensis (7%) sooty shearwaters Puffinus griseus (3%). Mortalities occurred mainly dumping wastes, more frequent winter, attended vessels. Average mortality rates 0.56 (95% confidence interval 0.32–0.82) per hour 0.21 (0.07–0.38) summer 0.09 (0.02–0.19) not winter. No absence summer. suffered a disproportionately rate, 15% drowning, compared 4% other species. Deaths resulting from entanglement nets affected M. capensis, at an average rate 3.0 (0.9–5.4) 100 trawls (n=331 trawls). Serious incidents independent age among albatrosses, but there was tendency for immature have higher interaction than adults. Crude extrapolation suggests that total is c. 18 000 (8000–31 000) year, which 85% nets. These same order magnitude as long-line bycatch waters. Mitigation measures been implemented reduce this fishery.