Bycatch mortality is a major factor contributing to shark population declines. Post-release mortality (PRM) is particularly difficult to quantify, limiting the accuracy of stock assessments. We paired blood-stress physiology with animal-borne accelerometers to quantify PRM rates of sharks caught in a commercial bottom longline fishery. Blood was sampled from the same individuals that were tagged, providing direct correlation between stress physiology and animal fate for sandbar (Carcharhinus plumbeus, N = 130), blacktip (C. limbatus, N = 105), tiger (Galeocerdo cuvier, N = 52), spinner (C. brevipinna, N = 14), and bull sharks (C. leucas, N = 14). PRM rates ranged from 2% and 3% PRM in tiger and sandbar sharks to 42% and 71% PRM in blacktip and spinner sharks, respectively. Decision trees based on blood values predicted mortality with >67% accuracy in blacktip and spinner sharks, and >99% accuracy in sandbar sharks. Ninety percent of PRM occurred within 5 h after release and 59% within 2 h. Blood physiology indicated that PRM was primarily associated with acidosis and increases in plasma potassium levels. Total fishing mortality reached 62% for blacktip and 89% for spinner sharks, which may be under-estimates given that some soak times were shortened to focus on PRM. Our findings suggest that no-take regulations may be beneficial for sandbar, tiger, and bull sharks, but less effective for more susceptible species such as blacktip and spinner sharks.

中文翻译：

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将释放后死亡率与商业延绳钓渔业中大型沿海鲨鱼的生理应激反应联系起来。

兼捕死亡率是导致鲨鱼数量下降的一个主要因素。释放后死亡率 (PRM) 特别难以量化，限制了库存评估的准确性。我们将血液压力生理学与动物加速度计相结合，以量化商业底层延绳钓渔业捕获的鲨鱼的 PRM 率。血液采样自被标记的相同个体，提供了沙洲（Carcharhinus pumpeus，N = 130）、黑鳍鲨（C.limbatus，N = 105）、老虎（Galeocerdo cuvier，N = 52）的应激生理和动物命运之间的直接相关性)、旋转器 (C. brevipinna, N = 14) 和牛鲨 (C. leucas, N = 14)。PRM 率从虎鲨和沙洲鲨的 PRM 的 2% 和 3% 到黑鳍鲨和飞旋鲨的 PRM 分别为 42% 和 71%。基于血值的决策树预测死亡率与> 黑鳍鲨和飞旋鲨的准确度为 67%，沙洲鲨的准确度超过 99%。90% 的 PRM 发生在释放后 5 小时内，59% 发生在 2 小时内。血液生理学表明 PRM 主要与酸中毒和血浆钾水平升高有关。黑鳍鲨的总捕捞死亡率达到 62%，飞旋鲨为 89%，鉴于缩短了一些浸泡时间以专注于 PRM，这可能被低估了。我们的研究结果表明，禁捕规定可能对沙洲鲨、虎鲨和牛鲨有益，但对黑鳍鲨和飞旋鲨等更易受影响的物种效果较差。血液生理学表明 PRM 主要与酸中毒和血浆钾水平升高有关。黑鳍鲨的总捕捞死亡率达到 62%，飞旋鲨为 89%，鉴于缩短了一些浸泡时间以专注于 PRM，这可能被低估了。我们的研究结果表明，禁捕规定可能对沙洲鲨、虎鲨和牛鲨有益，但对黑鳍鲨和飞旋鲨等更易受影响的物种效果较差。血液生理学表明 PRM 主要与酸中毒和血浆钾水平升高有关。黑鳍鲨的总捕捞死亡率达到 62%，飞旋鲨为 89%，鉴于缩短了一些浸泡时间以专注于 PRM，这可能被低估了。我们的研究结果表明，禁捕规定可能对沙洲鲨、虎鲨和牛鲨有益，但对黑鳍鲨和飞旋鲨等更易受影响的物种效果较差。