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首页> 外文期刊>ICES Journal of Marine Science >Walleye pollock respond to trawling vessels
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Walleye pollock respond to trawling vessels

机译：角膜白鳕对拖网渔船的反应

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The potential for fish to avoid survey vessels is a major source of uncertainty in stock-assessment surveys. Although walleye pollock (Theragra chalcogramma) are the subject of a substantial commercial fishery in the North Pacific, their behavioural responses to approaching survey vessels remain poorly understood. As a first step in an effort to determine if walleye pollock avoid survey vessels engaged in trawling operations, we made pairwise comparisons of acoustic backscatter recorded by survey vessels while free-running and while trawling. Results are presented of acoustic backscatter recorded from NOAA's RV "Miller Freeman", which used a midwater trawl during the 1996-2002 eastern Bering Sea surveys, and a chartered commercial fishing vessel, which used a bottom trawl during a survey in 2003 in the Gulf of Alaska. In both cases, average backscatter from a vessel-mounted echosounder was significantly higher when free-running than when trawling. These decreases in backscatter are consistent with increased vessel avoidance while trawling. There were no differences in the vertical distribution of backscatter when free-running and trawling, indicating that pollock do not exhibit elevated diving responses when approached by a trawling vessel rather than by a free-running vessel. Although the study indicates that pollock respond to trawling vessels, the nature of the behavioural response cannot be determined with the methods used in this study. Future work should evaluate potential stimuli produced by trawlers to which pollock may react, and should document changes in behaviour that may occur in their presence.
机译：鱼类避开调查船的潜力是种群评估调查不确定性的主要来源。尽管在北太平洋，角膜白斑鳕（Theragra chalcogramma）是大量商业性渔业的主题，但它们对接近调查船的行为反应仍知之甚少。作为确定角膜白斑鳕鱼是否避开调查船进行拖网作业的第一步，我们进行了成对比较，调查船在自由行驶和拖网时记录的声学反向散射。结果显示了从NOAA的RV“ Miller Freeman”号记录的声向后向散射，该声波在1996-2002年白令海东部勘测中使用了中水拖网，而一艘商用民用渔船在2003年的海湾调查中使用了底拖网阿拉斯加在这两种情况下，自由行驶时从船上安装的回声测深仪测得的平均反向散射都比拖网时高。反向散射的这些减少与拖网时避免船只的情况一致。自由航行和拖网捕捞时反向散射的垂直分布没有差异，这表明当用拖网渔船而不是自由航行渔船接近时，鳕鱼的潜水响应不会升高。尽管研究表明狭鳕对拖网渔船有反应，但行为反应的性质无法通过本研究中使用的方法确定。未来的工作应评估拖网渔船可能对之产生反应的潜在刺激，并应记录拖网渔船在场时可能发生的行为变化。

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