The impact of marine recreational fishing on key fish stocks in European waters
The impact of marine recreational fishing on key fish stocks in European waters
复制标题
海洋休闲捕鱼对欧洲水域主要鱼类种群的影响
作者：
Zachary Radford;K. Hyder;L. Zarauz;E. Mugerza;K. Ferter;R. Prellezo;H. Strehlow;B. Townhill;Wolf;M. S. Weltersbach
海洋休闲捕鱼（MRF）已被证明是海洋鱼类捕捞死亡率的主要原因。然而，欧洲管理成果框架的渔获量仅对少数种群进行了量化，因此不清楚是否有很大一部分渔捞死亡率被排除在种群评估之外。这项研究估计：（一）欧洲的管理参考框架清除量，其定义为上岸量加上死鱼释放量;（二）通过比较管理参考框架和商业捕鱼对总清除量的贡献百分比，说明对种群的影响。由于一些欧洲国家的管理成果框架数据有限，因此采用平均释放比例、平均鱼重和利用提供渔获量估计数的最近国家的渔民人均渔获量进行外推的混合方法来重建渔获量。如果渔获量重建超过50%，则将数据排除在进一步分析之外。此外，由于管理成果框架调查方法可能是可变的，因此计算了每种鱼类的偏倚和误差的半定量估计数。在本研究评估的20个种群中，只有10个种群有足够的管理成果框架数据，可以作出充分可靠的估计。MRF对总清除量（MRF +商业清除量）的贡献百分比在北海和斯卡格拉克的大西洋鲭鱼的2%和凯尔特海和英吉利海峡的大西洋鳕鱼的43%之间。被清除的生物量在297（± 116）吨（英吉利海峡西部和凯尔特海南部的大西洋鳕鱼）和4820（± 1889）吨（北海和斯卡格拉克的大西洋鲭鱼）之间，但误差很大。此外，在估计清除量的偏差是低的，为大多数股票，与一些积极的偏差found. The研究表明，MRF清除量可以代表一个高比例的总清除量的一些欧洲海洋鱼类种群，所以列入种群评估应该是例行的。为此，需要定期调查管理成果框架，以收集对种群评估至关重要的数据。
Marine recreational fishing (MRF) has been shown to substantially contribute to fishing mortality of marine fish. However, European MRF catches are only quantified for a small number of stocks, so it is unclear whether a significant part of fishing mortality is excluded from stock assessments. This study estimated: (i) European MRF removals, which were defined as landings plus dead releases; and (ii) impact at stock level by comparing the percentage contribution to total removal by MRF and commercial fishing. As MRF data were limited for some European countries, catches were reconstructed using a mixture of average release proportions, average fish weights, and extrapolation using the catch per fisher of the nearest country providing catch estimates. Where catch reconstructions exceeded 50%, data were excluded from further analysis. Furthermore, as MRF survey methodology can be variable, semi-quantitative estimates of bias and error were calculated for each stock. Only 10 of the 20 stocks assessed in this study had sufficient MRF data for full reliable estimates. Percentage contribution to total removals (MRF + commercial removals) by MRF ranged between 2% for Atlantic mackerel in the North Sea and Skagerrak and 43% for Atlantic pollack in the Celtic Seas and English Channel. The biomass removed ranged between 297 (± 116) tonnes (Atlantic cod in the western English Channel and southern Celtic seas) and 4820 (± 1889) tonnes (Atlantic mackerel in the North Sea and Skagerrak), but the errors were substantial. Additionally, the bias in the estimated removals was low for most stocks, with some positive biases found. The present study indicates that removals by MRF can represent a high proportion of the total removals for some European marine fish stocks, so inclusion in stock assessments should be routine. To achieve this, regular surveys of MRF are required to collect data essential for stock assessments.