With the rapid growth of grey seal (Halichoerus grypus) population in the Baltic Sea, seal-induced catch losses have increased dramatically in coastal fisheries. There have been various attempts to mitigate these damages, such as modification of fishing gear, but solutions have proven inadequate. Promising research results have recently been obtained by using acoustic deterrent devices (ADDs) to keep seals away from the immediate vicinity of the gear. We tested the feasibility and effectiveness of a raft-mounted and a novel mobile ADD in Baltic salmon (Salmo salar) trap-net fisheries along the Finnish coast in collaboration with 13 commercial fishers. Fishers operated trap-nets (pontoon traps) that were equipped with and without an ADD. Our results indicate that a fisher with a trap-net equipped with an ADD can expect to catch on average 3.4 salmon per day whereas in trap-net without an ADD a fisher can expect on average 2.1 salmon per day. The deployment of ADDs over the two years testing period indicated an average increase of 64% in salmon catches. Our study suggests that in salmon trap-net fisheries an ADD is a useful and economically viable (given that the investment is subsided) mitigation tool for reducing seal-induced catch losses. Furthermore, the mobile ADD developed in this study provides unique practical opportunities and notable potential for a wider use of an ADD.

随着波罗的海灰海豹（Halichoerus grypus）种群的快速增长，海豹引起的沿海渔业捕捞量损失急剧增加。已经有各种尝试来减轻这些损害，例如修改渔具，但解决方案已被证明是不够的。最近通过使用声学威慑装置 (ADD) 使密封件远离齿轮附近，获得了有希望的研究成果。我们在波罗的海鲑鱼（Salmo salar) 与 13 名商业渔民合作，在芬兰海岸进行捕网渔业。渔民操作的陷阱网（浮桥陷阱）配备和不配备 ADD。我们的结果表明，使用配备 ADD 的捕捞网的渔民平均每天可以捕捞 3.4 条鲑鱼，而在没有 ADD 的捕捞网中，渔民平均每天可以预期捕捞 2.1 条鲑鱼。在两年的测试期间部署 ADD 表明鲑鱼捕获量平均增加了 64%。我们的研究表明，在鲑鱼捕网渔业中，ADD 是一种有用且经济上可行的（鉴于投资减少）缓解工具，可减少海豹造成的渔获量损失。此外，本研究中开发的移动 ADD 为更广泛地使用 ADD 提供了独特的实践机会和显着的潜力。