Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
The European eel (Anguilla anguilla) is endangered due to its peculiar life-history cycle, fishing pressure and difficulty in global population management. To improve our understanding of the population dynamics and refine conservation policies, an extended mark and recapture experiment and glass eel stocking were conducted in the River Rhône Delta (France) over 8 years. Around 1100 yellow eels were PIT-tagged and released in 2007, 2.5 kg of glass eels were released each year from 2008 to 2012, and the population was monitored using fishing between 2007 and 2015. After capture or recapture, the body parameters, sex and maturity were assessed. Age was estimated from otolith growth rings. At the end of the experiment, silver eels were between 352 and 875 mm long (age 17 to 185 months) and yellow eels between 170 and 868 mm long (age 12 to 123 months). Age estimates were validated using mark and recapture and showed 16% age underestimates and 5% inaccurate ages. The growth rates were extremely variable with lengths ranged by 2-fold at a given age. These results highlight the difficulty of eel population management, at least in the Mediterranean area.

中文翻译：

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在法国南部进行的延长标记和重新捕获实验揭示了欧洲鳗鱼生长的极端变化以及对管理的影响

加拿大渔业和水生科学杂志，印刷前。
欧洲鳗鱼（Anguilla anguilla）因其独特的生活史周期、捕捞压力和全球种群管理困难而濒临灭绝。为了提高我们对种群动态的了解并完善保护政策，在罗纳河三角洲（法国）进行了为期 8 年的扩展标记和重新捕获实验以及玻璃鳗鱼放养。2007 年对大约 1100 条黄鳗进行了 PIT 标记和放流，2008 年至 2012 年每年释放 2.5 公斤玻璃鳗，并在 2007 年至 2015 年期间通过捕鱼对其种群进行监测。捕获或重新捕获后，其身体参数、性别和成熟度进行了评估。根据耳石生长环估计年龄。在实验结束时，银鳗长 352 至 875 毫米（17 至 185 个月龄），黄鳗长 170 至 868 毫米（12 至 123 个月龄）。使用标记和重新捕获验证了年龄估计，并显示 16% 的年龄低估和 5% 的年龄不准确。在给定年龄，生长速率变化很大，长度范围为 2 倍。这些结果突出了鳗鱼种群管理的困难，至少在地中海地区是这样。