Fisheries for forage fish may affect the survival and reproduction of piscivorous predators, especially seabirds. However, seabirds have evolved life history strategies to cope with natural fluctuations in prey and it is difficult to separate effects of fishing on seabirds from impacts of natural variability. To date, potential impacts of forage fisheries on seabirds have mainly been explored using ecosystem models that simplify seabird–forage-fish dynamics. We sought to explore how different forage fish harvest policies affect seabirds, accounting for structured population dynamics, life history specifics, and variation in forage fish dependencies across life stages; and how impacts vary across seabird and forage fish life histories. To explore these impacts, we developed an age-stage structured seabird model that incorporates seabird diet specialization, foraging behavior, and reproductive strategy, as well as different functional responses between prey availability and adult survival, juvenile survival, reproductive success, and breeder propensity. We parameterized this model for two contrasting seabird life histories: (1) a low fecundity, limited foraging range, diet specialist (“restricted”); and (2) a high fecundity, wide ranging, diet generalist (“flexible”). Each was paired with two different forage fish prey archetypes that were fished under various control rules. The restricted seabird population was expectedly less robust to constant fishing pressure than the flexible seabird, and this sensitivity was mainly due to functional response parameterization, rather than other life history parameters. Particularly, the restricted seabird was highly sensitive to the relationship between prey availability and adult survival but was not sensitive to the relationship between prey and reproductive success. An adaptive biomass-limit harvest rule for forage fish resulted in substantially higher seabird abundance compared to constant fishing across all scenarios, with minimal trade-offs to the fishery (depending on fishery management objectives). However, mechanisms governing the impact of the forage fish fishery on the seabird varied by forage fish type. Therefore, tailoring forage fish management strategies to forage fish life history can lead to mutually acceptable outcomes for fisheries and seabirds. If data or time are limited, an adaptive control rule is likely a safe bet for meeting seabird conservation objectives with limited impacts to fisheries.

中文翻译：

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结构化海鸟种群模型揭示了替代饲料鱼控制规则如何使海鸟和渔业受益

捕食饲料鱼可能会影响食肉性捕食者，尤其是海鸟的生存和繁殖。然而，海鸟已经进化出生活史策略来应对猎物的自然波动，很难将捕鱼对海鸟的影响与自然变化的影响区分开来。迄今为止，主要使用简化海鸟-饲料-鱼类动态的生态系统模型来探索饲料渔业对海鸟的潜在影响。我们试图探索不同的饲料鱼收获政策如何影响海鸟，解释结构化的种群动态、生活史细节以及不同生命阶段饲料鱼依赖性的变化；以及海鸟和饲料鱼生活史的影响如何变化。为了探索这些影响，我们开发了一个年龄阶段的结构化海鸟模型，该模型结合了海鸟饮食专业化、觅食行为和繁殖策略，以及猎物可用性与成年存活、幼年存活、繁殖成功和繁殖倾向之间的不同功能反应。我们为两种截然不同的海鸟生活史参数化了这个模型：（1）繁殖力低，觅食范围有限，饮食专家（“受限”）；(2) 繁殖力高、范围广、饮食通才（“灵活”）。每个都与两种不同的饲料鱼猎物原型配对，这些鱼在各种控制规则下捕捞。与灵活的海鸟相比，受限制的海鸟种群对恒定捕捞压力的稳健性较低，这种敏感性主要是由于功能响应参数化，而不是其他生活史参数。特别是，受限海鸟对猎物可用性和成虫存活率之间的关系高度敏感，但对猎物和繁殖成功率之间的关系不敏感。与所有情景中的持续捕捞相比，饲料鱼的适应性生物量限制捕捞规则导致海鸟丰度显着增加，对渔业的权衡最小（取决于渔业管理目标）。然而，管理饲料鱼渔业对海鸟影响的机制因饲料鱼类型而异。因此，根据饲料鱼的生活史调整饲料鱼管理策略可以为渔业和海鸟带来相互可接受的结果。如果数据或时间有限，