School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America.
PLoS One. 2013 Jul 24;8(7):e69615. doi: 10.1371/journal.pone.0069615. Print 2013.
Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention). Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement from commercial gear compromise reproductive success in spawning stocks of Pacific salmon (Oncorhynchus spp.). We found evidence for elevated stress in fish injured via non-retention in gillnet fisheries. Plasma cortisol levels correlated with the severity of disentanglement injury and were elevated in fish that developed infections related to disentanglement injuries. We also analyzed sex steroid concentrations in females (estradiol-17β and 17,20β-dihydroxy-4-pregnen-3-one) to determine whether non-retention impairs reproductive potential in escaped individuals. We demonstrate evidence for delayed or inhibited maturation in fish with disentanglement injuries. These findings have important implications for effective conservation and management of exploited fish stocks and suggest means to improve spawning success in such stocks if retention in commercial fisheries is improved and incidental mortality reduced.
渔业资源的开发利用带来了意想不到的后果，不仅在副渔获物和非目标生物的丢弃方面，而且在因渔具而受伤但未被捕获的目标鱼类（未保留）方面也是如此。由于未保留而导致的延迟死亡代表了被开发种群中失去的繁殖潜力，而不会对收获做出贡献。我们的研究检查了延迟死亡发生的生理机制，以及与商业渔具纠缠相关的伤害在太平洋鲑鱼（Oncorhynchus spp.）产卵种群中对繁殖成功的影响程度。我们发现了在刺网渔业中因未保留而受伤的鱼类中应激水平升高的证据。血浆皮质醇水平与纠缠损伤的严重程度相关，并且在与纠缠损伤相关的感染中发展的鱼类中升高。我们还分析了雌性（雌二醇-17β和 17,20β-二羟基-4-孕烯-3-酮）中的性类固醇浓度，以确定未保留是否会损害逃脱个体的繁殖潜力。我们证明了在有纠缠损伤的鱼类中存在成熟延迟或抑制的证据。这些发现对受开发鱼类种群的有效保护和管理具有重要意义，并表明如果商业渔业中的保留得到改善和偶然死亡率降低，那么可以改善此类种群的繁殖成功率。
