Uhlmann Sven Sebastian, Paoletti Silvia, Ampe Bart, Theodoridis Konstantinos, Kochzius Marc, Koeck Barbara
Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Animal Sciences Unit, Fisheries and Aquatic Production, Jacobsenstraat 1, 8400 Ostend, Belgium.
Marine Biology - Ecology, Evolution & Genetics, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
Conserv Physiol. 2024 Jun 13;12(1):coae036. doi: 10.1093/conphys/coae036. eCollection 2024.
Thermal stress can influence the recovery of fish released after capture. Vitality assessments using reflex and behavioural responses require that responses can be observed reliably, independent of temperature. Here, we tested whether reflex and behavioural impairment and survival of beam-trawled and discarded European plaice () are independent from seasonal air and water temperature deviations. In total, 324 beam-trawled plaice ( = 196 in summer and = 128 in winter) were exposed to two air temperature treatments and two water treatments (i.e. modified and ambient temperatures for both). The modified treatments (i.e. cooled in summer, warmed in winter) represent the thermal shock a fish may experience when being returned to the water. All reflexes and tested behaviours were affected by ambient temperature, with high impairment noted in summer. None of the reflexes were affected by temperature shocks alone, only body flex was. Body flex was highly impaired under every exposure combination. Fish size and duration of air exposure further influenced impairment of reflexes such as head complex and tail grab. More generally, post-release survival was assessed as 21% [95% CI: 16-28%] in summer and 99% [97-100%] in winter. Beam trawling in summer is likely to induce high reflex impairment and mortality in discarded plaice, and therefore spatial-temporal mitigation approaches should be prioritized over control of on-board temperatures.
热应激会影响捕获后放流鱼类的恢复情况。利用反射和行为反应进行的活力评估要求能够可靠地观察到反应，且不受温度影响。在此，我们测试了桁拖网捕捞并丢弃的欧洲鲽（）的反射和行为损伤以及存活率是否不受季节性空气和水温偏差的影响。总共324尾桁拖网捕捞的鲽（夏季196尾，冬季128尾）接受了两种空气温度处理和两种水温处理（即改良温度和环境温度）。改良处理（即夏季降温，冬季升温）代表了鱼类放回水中时可能经历的热冲击。所有反射和测试行为均受环境温度影响，夏季损伤程度较高。没有任何反射仅受温度冲击影响，只有身体弯曲受影响。在每种暴露组合下，身体弯曲的损伤程度都很高。鱼的大小和暴露在空气中的持续时间进一步影响了诸如头部复合体和抓尾等反射的损伤程度。更普遍地说，放流后的存活率在夏季评估为21% [95%置信区间：16 - 28%]，在冬季为99% [97 - 100%]。夏季桁拖网捕捞很可能会导致丢弃的鲽出现高度反射损伤和死亡，因此时空缓解措施应优先于船上温度控制。
