IFREMER, Unité de Sciences et Technologies halieutiques, Laboratoire de Technologie et Biologie Halieutique, 8 rue François Toullec, F-56100, Lorient, France.
IFREMER, Unité de Sciences et Technologies halieutiques, Laboratoire de Technologie et Biologie Halieutique, 8 rue François Toullec, F-56100, Lorient, France.
J Environ Manage. 2017 Dec 15;204(Pt 1):404-412. doi: 10.1016/j.jenvman.2017.08.046. Epub 2017 Sep 12.
Species that have a high likelihood of surviving the discarding process have become great concern since the European Union reformed the Common Fisheries Policy and enacted a landing obligation prohibiting the discarding any individuals of species under quota. Among species presenting an elevated survival potential, plaice (Pleuronectes platessa) is one of the most discarded in the coastal otter trawl fishery in the English Channel. The objective of this study is to provide the most reliable estimates of plaice survival after release in commercial conditions, and to identify the factors that influence survival rates. A captivity experiment was conducted in January-February in the English fishery to assess the survival of discarded plaice as a function of a semi-quantitative index of fish vitality, which has been demonstrated to be a good proxy of fish survival in comparable fishing and environmental conditions. This study examined the potential of this index to estimate discard survival in three trials from the English and French fisheries and at three different seasons. The vitality index was then used to analyse the influence of several factors (fishing practices, environmental conditions and fish biological characteristics) on the discard survival. The survival rates for plaice were accurately estimated at 62.8% in January-February, 66.6% in November and 45.2% in July. While these rates remained substantial whatever the fishing, environmental or fish biological conditions, the time fish spent on the deck, the bottom and air temperatures, the tow depth and the fish length had a significant influence on plaice survival. In practice, plaice survival could be enhanced by releasing the fish early during catch sorting and avoiding exposure to extreme air temperatures.
物种在丢弃过程中有很高的存活可能性，这引起了极大的关注，因为欧盟改革了共同渔业政策，并颁布了一项上岸义务，禁止丢弃任何配额内的个体。在具有高存活潜力的物种中，欧鲽（Pleuronectes platessa）是在英吉利海峡沿海延绳钓渔业中丢弃最多的物种之一。本研究的目的是提供商业条件下欧鲽释放后存活的最可靠估计，并确定影响存活率的因素。在一月至二月的英国渔业中进行了一项圈养实验，以评估丢弃的欧鲽的存活率，作为鱼类活力的半定量指数的函数，该指数已被证明是在类似的捕捞和环境条件下评估鱼类存活率的良好替代指标。本研究在英、法渔业的三次试验中检验了该指数在三种不同季节估算丢弃存活率的潜力。然后，利用活力指数分析了几个因素（捕捞实践、环境条件和鱼类生物学特性）对丢弃存活率的影响。在一月至二月、十一月和七月，欧鲽的存活率分别准确估计为 62.8%、66.6%和 45.2%。尽管这些存活率在任何捕捞、环境或鱼类生物学条件下都很高，但鱼在甲板上、底部和空气中停留的时间、拖网深度和鱼的长度对欧鲽的存活有显著影响。实际上，通过在捕捞分拣时尽早释放鱼并避免暴露在极端的空气温度下，可以提高欧鲽的存活率。
