When caught in a trawl, some individuals interacting with the fishing gear may escape, but such interactions may lead to physiological trauma that causes direct delayed mortality and/or increased vulnerability to predation. Understanding fishery-induced stress levels and the recovery period of escapees is therefore crucial for predicting total fishing-induced mortality. Hemolymph lactate concentration is commonly used as an index of physiological stress in many crustacean species, and the clearing time of lactate back to normal levels indicates the ability to recover from stress. We measured the hemolymph lactate concentration in three groups of Antarctic krill (Euphausia superbaDana, 1850): Group 1, trawl escapees collected during fishing; Group 2, specimens subjected to simulated mesh penetration; and Group 3, an onboard acclimated control group. Individuals that had escaped the trawl during fishing had the highest concentrations of hemolymph lactate (mean > 6 mmol–l). Exposure to mesh penetration was in itself not stressful, as hemolymph lactate concentrations did not differ significantly between Group 2 and the control Group (mean 0.8 mmol–lversus 0.7 mmol–l, respectively). Additional stress factors during the capture and handling process likely added to the elevated lactate levels observed in Group 1. For the trawl escapees, the lactate clearance time during stress recovery was modeled as a function of exponential decay. Hemolymph lactate levels did not differ significantly among the three groups after 200 min, which suggested that Antarctic krill recovered from fishery-induced stress within this time period.

中文翻译：

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南极磷虾 Euphausia superba Dana，1850 (Euphausiacea) 拖网逃逸的生理压力和恢复动力学

当被拖网捕获时，一些与渔具相互作用的个体可能会逃脱，但这种相互作用可能会导致生理创伤，从而导致直接延迟死亡和/或增加对捕食的脆弱性。因此，了解渔业引起的压力水平和逃生者的恢复期对于预测渔业引起的总死亡率至关重要。血淋巴乳酸浓度通常用作许多甲壳类动物生理应激的指标，乳酸清除至正常水平的时间表明其从应激中恢复的能力。我们测量了三组南极磷虾 (Euphausia superbaDana, 1850) 的血淋巴乳酸浓度： 第一组，在捕鱼期间收集的拖网逃逸；第 2 组，经受模拟网格穿透的试样；第 3 组，一个机载适应控制组。在捕鱼期间逃离拖网的个体具有最高浓度的血淋巴乳酸（平均值 > 6 mmol-l）。暴露于网状渗透本身并没有压力，因为第 2 组和对照组之间的血淋巴乳酸浓度没有显着差异（分别为 0.8 mmol-l 和 0.7 mmol-l）。捕获和处理过程中的其他压力因素可能会增加第 1 组中观察到的乳酸水平升高。对于拖网逃逸者，压力恢复期间的乳酸清除时间被建模为指数衰减的函数。200分钟后，三组之间的血淋巴乳酸水平没有显着差异，这表明南极磷虾在这段时间内从渔业引起的压力中恢复过来。