ABSTRACT: The current level of annual incidental bycatch of gray seals Halichoerus grypus in the New England sink gillnet fishery is the highest for all marine mammal species in the USA. One way to evaluate the risk of bycatch is to examine the risk of encounter between an animal and fishing gear based on the animal's habitat use in relation to fishing activity. Here we used satellite telemetry deployed on 30 gray seal pups in 2019 and 2020 to measure the risk of encounter with large-mesh sink gillnet fishing effort throughout the Gulf of Maine and southern New England. We estimated relative encounter risk within 30 min grid cells in each calendar quarter based on the overlap of seal presence and fishing effort, and then validated the expected risk based on bycatch events reported by independent observers on board fishing vessels. The relative risk of seals encountering gillnet fishing gear was highest off southeastern Massachusetts in spring. Patterns in the estimated encounter risk fit our expectation that relatively high levels of habitat use and fishing effort correspond to increased encounter risk. The approach taken here can be used to identify times and areas of high encounter risk to justify altered fishing practices for purposes of avoidance, or to target observer monitoring intended to characterize and quantify bycatch. Mitigation strategies will need to be continuously monitored and updated to incorporate new information as conflicts with fisheries and gray seals are likely to continue.

中文翻译：

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追踪年幼的灰海豹 Halichoerus grypus 以估计渔业遭遇风险

摘要：灰海豹Halichoerus grypus年度偶然兼捕的当前水平在新英格兰水槽中，刺网渔业是美国所有海洋哺乳动物物种中最高的。评估兼捕风险的一种方法是根据与捕鱼活动相关的动物栖息地用途来检查动物与渔具之间相遇的风险。在这里，我们使用了在 2019 年和 2020 年部署在 30 只灰海豹幼崽上的卫星遥测技术，以测量在整个缅因湾和新英格兰南部遇到大网孔刺网捕鱼活动的风险。我们根据海豹存在和捕捞努力的重叠估计了每个日历季度 30 分钟网格单元内的相对遭遇风险，然后根据独立观察员在渔船上报告的兼捕事件验证了预期风险。春季，马萨诸塞州东南部海域海豹遭遇刺网渔具的相对风险最高。估计遭遇风险的模式符合我们的预期，即相对高水平的栖息地利用和捕捞努力与增加的遭遇风险相对应。此处采用的方法可用于确定高遭遇风险的时间和区域，以证明为避免目的而改变捕捞方法的合理性，或用于目标观察者监测，旨在表征和量化兼捕。由于与渔业和灰海豹的冲突可能会继续存在，因此需要持续监测和更新缓解策略以纳入新信息。此处采用的方法可用于确定高遭遇风险的时间和区域，以证明为避免目的而改变捕捞方法的合理性，或用于目标观察者监测，旨在表征和量化兼捕。由于与渔业和灰海豹的冲突可能会继续存在，因此需要持续监测和更新缓解策略以纳入新信息。此处采用的方法可用于确定高遭遇风险的时间和区域，以证明为避免目的而改变捕捞方法的合理性，或用于目标观察者监测，旨在表征和量化兼捕。由于与渔业和灰海豹的冲突可能会继续存在，因此需要持续监测和更新缓解策略以纳入新信息。