A review of cetacean interactions with longline gear

摘要: Fishery-cetacean interactions, including those with longline gear, give rise to economic, ecological and social concerns. This paper reviews problems resulting from cetacean-longline considers potential strategies reduce interactions identifies research priorities approaches. Depredation by cetaceans (removal damage of hooked fish bait fishing gear) loss gear create economic problems; however, the magnitude this problem is poorly understood. There also insufficient information determine whether there are population-level effects injury mortality (from incidental entanglement hooking deliberate actions discourage depredation). may also: change cetacean foraging behaviour distribution; increase effort make up for taken cetaceans; errors in stock assessments that do not account depredation. Negative public perceptions can result news incidental associated longlining. Information on how limited, as understanding mechanisms responsible them. Strategies already employed some fleets include refraining setting or cutting sets short when problematic species observed fleet coordination daily times positions. Many fishermen perceive depredation an inevitable part of fishing. discusses a number other possible avoidance warrant consideration, including: (1) communication enable vessels avoid temporally spatially unpredictable sporadic hotspots aggregations (2) underwater acoustic masking devices conceal sound vessel, hauling activities; (3) quieter cetaceans’ ability target vessels; (4) encasement caught access interest catch; (5) use unpleasant smell taste attractiveness catch (6) prerecorded vessel sounds played stations throughout fleet’s grounds distract actual (7) mask returning echolocation signals; (8) tethered sonobuoys track avoidance. Vessels relatively low interaction rates should be examined design and operational differences high rates, possibly allowing identification effective methods. need experimentation individual fisheries over several seasons assess fisheryspecific efficacy commercial viability strategies. necessary different likely respond differently method habituate strategy, especially interacting resident cetaceans.