Abstract

Fisheries managed with explicit annual catch limits often have realized catches below the total allowable catch. Carry-over provisions allowing aggregate or individual carry-forward of catch underages are included in many fishery management systems, but the ramifications of these provisions on different fishery management objectives such as average catch, variability in catch, and probability and degree of overfishing are not well understood. We developed a management strategy evaluation simulation to explore performance of alternative carry-over policies assuming different life histories and under different causes of catch underages. We evaluated the impacts of the carry-overs across common management objectives to understand the trade-offs associated with different amounts of allowable carry-over. We find that carry-overs can increase yield to the fishery but can also increase the risks of overfishing, low stock biomass, low catch, and the interannual variability in catch. All of these risk measures increase with the amount of carry-over allowed in most cases, but for cases of low stock productivity or positively biased stock assessment estimates, larger carry-over allowances resulted in similar or lower yield compared to smaller allowances. The analysis suggests that some benefits of carry-over can be maintained and risks can be limited by restricting the maximum carry-over allowed.

中文翻译：

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允许在年限之间结转限额时在渔业管理目标中进行权衡

摘要

有明确的年度捕捞限额管理的渔业通常实现的捕捞量低于允许的总捕捞量。许多渔业管理系统都包括允许全部或单独捕捞未成年者的结转规定，但这些规定对不同渔业管理目标（例如平均产量，产量变化以及过度捕捞的可能性和程度）的影响并未包括在内。非常明白。我们开发了一种管理策略评估模拟，以探索假设不同的生活历史和不同的捕获不足年龄原因的替代结转政策的绩效。我们评估了共同管理目标中结转的影响，以了解与不同数量的允许结转相关的权衡。我们发现，残留物可以增加渔业产量，但也可能增加过度捕捞，种群生物量低，捕捞量低以及捕捞量年际变化的风险。在大多数情况下，所有这些风险措施都会随着允许的结转数量而增加，但是，对于较低的库存生产率或正的库存评估估计而言，与较小的准备金相比，较大的结转准备金会导致相似或较低的收益。分析表明，可以限制结转的最大结余，从而可以保留结转的某些收益，并可以限制风险。但是对于低股票生产率或正偏存量评估估计的情况，与较小的备抵相比，较大的结转津贴导致了相似或较低的收益。分析表明，可以限制结转的最大结余，从而可以保留结转的某些收益，并可以限制风险。但是对于低库存生产率或正偏存量评估估计的情况，与较小的备抵相比，较大的结转津贴导致了相似或较低的收益。分析表明，可以限制结转的最大结余，从而可以保留结转的某些收益，并可以限制风险。