Munday Emily S, Tissot Brian N, Heidel Jerry R, Miller-Morgan Tim
School of the Environment, Washington State University Vancouver , Vancouver, WA , USA.
Marine Laboratory, Humboldt State University , Trinidad, CA , USA.
PeerJ. 2015 Feb 17;3:e756. doi: 10.7717/peerj.756. eCollection 2015.
Each year, over 45 countries export 30 million fish from coral reefs as part of the global marine ornamental aquarium trade. This catch volume is partly influenced by collection methods that cause mortality. Barotrauma in fish resulting from forced ascent from depth can contribute to post-collection mortality. However, implementing decompression stops during ascent can prevent barotrauma. Conversely, venting (puncturing the swim bladder to release expanded internal gas) following ascent can mitigate some signs of barotrauma like positive buoyancy. Here, we evaluate how decompression and venting affect stress and mortality in the Yellow Tang (Zebrasoma flavescens). We examined the effects of three ascent treatments, each with decompression stops of varying frequency and duration, coupled with or without venting, on sublethal effects and mortality using histology and serum cortisol measurements. In fish subjected to ascent without decompression stops or venting, a mean post-collection mortality of 6.2% occurred within 24 h of capture. Common collection methods in the fishery, ascent without decompression stops coupled with venting, or one long decompression stop coupled with venting, resulted in no mortality. Histopathologic examination of heart, liver, head kidney, and swim bladder tissues in fish 0d and 21d post-collection revealed no significant barotrauma- or venting-related lesions in any treatment group. Ascent without decompression stops resulted in significantly higher serum cortisol than ascent with many stops, while venting alone did not affect cortisol. Future work should examine links in the supply chain following collection to determine if further handling and transport stressors affect survivorship and sublethal effects.
作为全球海洋观赏水族贸易的一部分，每年有超过45个国家从珊瑚礁出口3000万条鱼类。这个捕捞量部分受到导致鱼类死亡的捕捞方法的影响。鱼类因从深处被迫上升而产生的气压伤会导致捕捞后死亡。然而，在上升过程中实施减压停留可以预防气压伤。相反，上升后排气（刺破鱼鳔以释放膨胀的内部气体）可以减轻一些气压伤的症状，如正浮力。在这里，我们评估减压和排气如何影响黄尾吊（黄高鳍刺尾鱼）的应激和死亡率。我们研究了三种上升处理方式的效果，每种方式都有不同频率和持续时间的减压停留，再加上或不加上排气，通过组织学和血清皮质醇测量来研究对亚致死效应和死亡率的影响。在没有减压停留或排气的上升处理的鱼类中，捕获后24小时内平均捕捞后死亡率为6.2%。渔业中常见的捕捞方法，即没有减压停留加上排气的上升，或一次长时间减压停留加上排气，均未导致死亡。对捕捞后0天和21天的鱼类心脏、肝脏、头肾和鱼鳔组织进行组织病理学检查发现，任何处理组均未出现与气压伤或排气相关的明显病变。没有减压停留的上升导致血清皮质醇水平显著高于多次减压停留的上升，而单独排气对皮质醇没有影响。未来的工作应该研究捕捞后供应链中的联系，以确定进一步的处理和运输应激源是否会影响存活率和亚致死效应。
