Department of Zoology, University of Otago, Dunedin 9054, New Zealand;
Department of Zoology, University of Otago, Dunedin 9054, New Zealand.
Proc Natl Acad Sci U S A. 2017 Oct 31;114(44):11781-11786. doi: 10.1073/pnas.1703165114. Epub 2017 Oct 9.
Declines of marine megafauna due to fisheries by-catch are thought to be mitigated by exclusion devices that release nontarget species. However, exclusion devices may instead conceal negative effects associated with by-catch caused by fisheries (i.e., unobserved or discarded by-catch with low postrelease survival or reproduction). We show that the decline of the endangered New Zealand (NZ) sea lion () is linked to latent levels of by-catch occurring in sub-Antarctic trawl fisheries. Exclusion devices have been used since 2001 but have not slowed or reversed population decline. However, 35% of the variability in NZ sea lion pup production is explained by latent by-catch, and the population would increase without this factor. Our results indicate that exclusion devices can obscure rather than alleviate fishery impacts on marine megafauna.
由于渔业副渔获物而导致的海洋巨型动物数量减少，据认为可以通过释放非目标物种的排除设备来缓解。然而，排除设备反而可能掩盖与渔业副渔获物相关的负面影响（即未被观察到或丢弃的副渔获物，其生存或繁殖后的存活率较低）。我们表明，濒临灭绝的新西兰海狮（）的减少与亚南极拖网渔业中潜在的副渔获物水平有关。自 2001 年以来，一直使用排除设备，但并未减缓或扭转种群减少的趋势。然而，新西兰海狮幼崽产量的 35%可以通过潜在的副渔获物来解释，如果没有这个因素，种群数量将会增加。我们的研究结果表明，排除设备可能会掩盖而不是减轻渔业对海洋巨型动物的影响。
