Abstract To prevent unwanted fish bycatch from entering the trawl, we modified a counter-herding device, FLEXSELECT, developed for a Northeast Atlantic Nephrops (Nephrops norvegicus) trawl fishery. FLEXSELECT, which was designed to direct fish away from the trawl by means of sweeping ropes in the herding area, has been shown to be highly effective on both roundfish and flatfish species. However, by adding sweeping elements we could be increasing the benthic impact of trawling. Therefore, in this study we investigated if the effect of FLEXSELECT can be maintained when raising the ropes off the seabed. A reduction in fish bycatch could still be achieved, but the effect of FLEXSELECTraised with respect to the previous design was significantly different for four of the seven species analysed. While for some species the effect was lower, it substantially increased for cod (Gadus morhua), making it highly relevant for the Nephrops fisheries, as well as for other fisheries in needs of avoiding cod catches. The results offer insights regarding species behavioural responses to FLEXSELECTraised, to be used for future developments of counter-herding devices in commercial fisheries without the addition of seabed impact to the baseline gears.

中文翻译：

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反放牧装置的效率是否取决于海底接触？

摘要 为了防止不需要的鱼兼捕物进入拖网，我们改进了一种反放牧装置 FLEXSELECT，该装置是为东北大西洋 Nephrops (Nephrops norvegicus) 拖网渔业开发的。FLEXSELECT 旨在通过在放牧区通过清扫绳将鱼引离拖网，已被证明对圆鱼和比目鱼都非常有效。然而，通过添加清扫元素，我们可以增加拖网捕鱼的底栖影响。因此，在这项研究中，我们调查了在将绳索抬离海床时是否可以保持 FLEXSELECT 的效果。仍然可以减少鱼类兼捕，但 FLEXSELECTraised 相对于先前设计的效果对于分析的七个物种中的四个有显着差异。虽然对于某些物种，效果较低，鳕鱼 (Gadus morhua) 的数量大幅增加，使其与 Nephrops 渔业以及需要避免捕获鳕鱼的其他渔业高度相关。结果提供了有关 FLEXSELECTraised 的物种行为反应的见解，可用于商业渔业中反放牧设备的未来发展，而不会对基线渔具增加海床影响。