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首页> 外文期刊>ICES Journal of Marine Science >Overfishing of marine resources: some lessons from the assessment of demersal stocks off Mauritania
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Overfishing of marine resources: some lessons from the assessment of demersal stocks off Mauritania

机译：海洋资源过度捕捞：评估毛里塔尼亚外海沉没种群的一些教训

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摘要

The recent, rapid development of fishing in Mauritania offers a good case study for a comparative approach of the resilience of the species exploited there, in the face of increasing fishing pressure. First, we assessed the health of 22 demersal stocks with differing ecological requirements, demographic strategies, and states of exploitation. A dynamic production model was fitted in a framework of Bayesian statistics to abundance indices estimated from scientific trawl surveys or commercial catch per unit efforts. We show that 12 of the 22 stocks assessed are overexploited and 3 are fully exploited. The combined assessment of all 22 stocks demonstrates an overall overexploitation, with total demersal biomass decreasing by similar to 75% since 1982 and fishing effort 30% higher than that at maximum sustained yield (40% higher for finfish). Second, relations between states of stocks and life history traits were analysed. The stocks of large and vulnerable species currently undergo the highest fishing pressure and are those that are the most overexploited. At the scale of the community represented by the stocks considered, surveys-based indictors of the mean intrinsic vulnerability, the mean maximum length, and the mean trophic level exhibit a significant decrease from 1990 to 2010. Changes observed in catch-based indicators depend on fishing strategies and are impacted by the recent development of the small-scale fishery. But indicators expressed as a function of a multiplier of fishing effort or fishing mortality clearly decrease, thus confirming that the intensification of exploitation leads to communities dominated by smaller species and lower trophic levels. We conclude that large and high trophic level species, such as white grouper, meagre, guitarfish, and smooth-hound, are markers of ecosystem health and should be considered as sentinel species.
机译：毛里塔尼亚近来捕捞业的迅速发展为面对捕捞压力不断增加的当地物种的复原力提供了一种比较方法的很好的案例研究。首先，我们评估了22种不同生态需求，人口统计学策略和开发状况的深海种群的健康状况。在贝叶斯统计框架内，采用了动态生产模型，以根据科学拖网调查或每单位努力的商业捕捞量估算出的丰度指数。我们显示，评估的22种股票中有12种被过度开发，其中3种被充分利用。对全部22种种群的综合评估表明，总体上过度捕捞，自1982年以来总沉没生物量减少了约75％，捕捞努力比最大持续产量高30％（有鳍鱼类增加40％）。其次，分析了股票状态与生活史特征之间的关系。当前，大型和脆弱物种的种群承受着最高的捕捞压力，并且是最被过度利用的种群。在所考虑的种群所代表的社区范围内，基于调查的指标的平均内在脆弱性，平均最大长度和平均营养水平在1990年至2010年期间显着下降。基于渔获量的指标的变化取决于捕捞策略，并受到近期小型渔业发展的影响。但是，表示为捕捞努力倍数或捕捞死亡率倍数的函数的指标明显下降，因此证实了剥削的加剧导致以较小物种和较低营养水平为主的社区。我们得出的结论是，大型和高营养水平的物种，例如白斑，石斑鱼，吉它鱼和猎犬，是生态系统健康的标志，应被视为前哨物种。

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