Abstract Found in the coastal waters of all continents, gillnets are the largest component of small-scale fisheries for many countries. Numerous studies show that these fisheries often have high bycatch rates of threatened marine species such as sea turtles, small cetaceans and seabirds, resulting in possible population declines of these non-target groups. However, few solutions to reduce gillnet bycatch have been developed. Recent bycatch reduction technologies (BRTs) use sensory cues to alert non-target species to the presence of fishing gear. In this study we deployed light emitting diodes (LEDs) - a visual cue - on the floatlines of paired gillnets (control vs illuminated net) during 864 fishing sets on small-scale vessels departing from three Peruvian ports between 2015 and 2018. Bycatch probability per set for sea turtles, cetaceans and seabirds as well as catch per unit effort (CPUE) of target species were analysed for illuminated and control nets using a generalised linear mixed-effects model (GLMM). For illuminated nets, bycatch probability per set was reduced by up to 74.4 % for sea turtles and 70.8 % for small cetaceans in comparison to non-illuminated, control nets. For seabirds, nominal BPUEs decreased by 84.0 % in the presence of LEDs. Target species CPUE was not negatively affected by the presence of LEDs. This study highlights the efficacy of net illumination as a multi-taxa BRT for small-scale gillnet fisheries in Peru. These results are promising given the global ubiquity of small-scale net fisheries, the relatively low cost of LEDs and the current lack of alternate solutions to bycatch.

中文翻译：

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减少秘鲁小规模刺网渔业兼捕的一个有启发性的想法

摘要 刺网遍布各大洲的沿海水域，是许多国家小型渔业的最大组成部分。大量研究表明，这些渔业往往对海龟、小型鲸类和海鸟等受威胁海洋物种的兼捕率很高，导致这些非目标群体的种群数量可能下降。然而，几乎没有开发出减少刺网兼捕的解决方案。最近的兼捕减少技术 (BRT) 使用感官线索提醒非目标物种注意渔具的存在。在这项研究中，我们在 2015 年至 2018 年间从秘鲁三个港口出发的小型船只上的 864 次捕鱼组期间，在成对刺网（控制网与照明网）的浮线上部署了发光二极管 (LED) - 一种视觉提示。为海龟而设，使用广义线性混合效应模型 (GLMM) 分析了鲸类和海鸟以及目标物种的单位努力捕获量 (CPUE) 的照明和控制网。对于照明网，与非照明控制网相比，海龟的每套误捕概率降低了 74.4%，小型鲸类的误捕概率降低了 70.8%。对于海鸟，在 LED 存在的情况下，标称 BPUE 降低了 84.0%。LED 的存在并未对目标物种 CPUE 产生负面影响。这项研究强调了网照明作为秘鲁小规模刺网渔业的多类群 BRT 的功效。鉴于全球普遍存在小规模净捕捞、LED 成本相对较低以及目前缺乏兼捕的替代解决方案，这些结果是有希望的。