Institute of Environmental Science and Technology, ICTA, Universitat Autònoma de Barcelona, Barcelona, Spain.
PLoS One. 2013 Jul 26;8(7):e69959. doi: 10.1371/journal.pone.0069959. Print 2013.
The Eastern Atlantic and Mediterranean stock of Bluefin tuna Thunnus thynnus (BFTE) has long been considered overfished and at risk of collapse. Although ICCAT quotas for this stock have decreased considerably over the past years, uncertainty exists about the degree of catch beyond this quota. The extent of such catch is an important piece of information in stock assessment models as well as being an indicator of the effectiveness of fisheries management. We present a model using Bluefin tuna trade data to infer actual catches. Basing our calculations on 25 countries involved in BFTE trade, we estimate that between 2005 and 2011, allowable quotas were exceeded by 44 percent. This gap between catch and quotas has slightly increased over past years, leading to estimated excess catches of 57 percent for the period between 2008 and 2011. To improve assessments, preparation and design of BFTE management, we suggest that the estimated total removals reported in this paper be included in stock assessment models for BFTE. An implication of our findings is that ICCAT member states should take stronger measures to monitor and enforce compliance with quotas.
东大西洋和地中海金枪鱼种群（BFTE）长期以来一直被认为过度捕捞，处于崩溃的危险之中。尽管 ICCAT 对该种群的配额在过去几年中大幅减少，但仍存在超过该配额的捕捞量的不确定性。这种捕捞的程度是库存评估模型中的一个重要信息，也是渔业管理有效性的一个指标。我们提出了一个使用金枪鱼贸易数据来推断实际捕捞量的模型。我们的计算基于 25 个参与 BFTE 贸易的国家，估计 2005 年至 2011 年期间，允许的配额被超额捕捞了 44%。过去几年中，这种捕捞量与配额之间的差距略有增加，导致 2008 年至 2011 年期间的估计过度捕捞量为 57%。为了改善评估，我们建议在 BFTE 管理的准备和设计中，将本文报告的估计总捕捞量纳入到 stock assessment models 中。我们研究结果的一个含义是，ICCAT 成员国应采取更强有力的措施来监测和执行配额。
