Abstract

How do we assess the performance of national and international fisheries management organizations? Many organizations produce measures of the extent of overfishing, typically classifying individual stocks as overfished if they are below some biomass threshold. Most agencies then report their overall status (i.e. percentage overfished, fully exploited, etc.) by giving equal weight to all stocks, regardless of stock size or potential yield. We review the range of indices used to assess overfishing levels and apply them to the data from US fisheries to show how they depict very different performance of fisheries. Given that overfishing is a concept imbedded in the maximization of long-term harvest, we evaluate how well these indices reflect the extent to which fisheries have maximized sustainable yield. Indices that are weighted by the potential yield of the stock much better reflect the regional performance of fisheries but are still limited by the arbitrary use of a threshold abundance. For the United States, weighting by maximum sustainable yield or value suggests that the losses from overfishing are less than existing methods using equal weighting and that underfishing is much more common than overfishing.

中文翻译：

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衡量渔业管理绩效

摘要

我们如何评估国家和国际渔业管理组织的绩效？许多组织制定了过度捕捞程度的度量标准，通常将单个种群如果低于某些生物量阈值，则分类为过度捕捞。然后，大多数机构通过对所有种群给予同等权重来报告其总体状况（即，过度捕捞，充分开发的百分比等），而不论种群大小或潜在产量。我们回顾了用于评估过度捕捞水平的指数范围，并将其应用于美国渔业数据中，以显示它们如何描绘出完全不同的渔业表现。鉴于过度捕捞是长期捕捞最大化的一个根基，我们评估这些指标在多大程度上反映了渔业实现可持续产量最大化的程度。由种群的潜在产量加权的指数能更好地反映渔业的区域表现，但仍然受到任意使用阈值丰度的限制。对于美国，按最大可持续产量或价值进行加权表明，过度捕捞造成的损失要小于采用相同加权的现有方法，而过度捕捞比过度捕捞更为普遍。