In this paper, we present a simple theoretical, steady-state equilibrium, predator-prey model for the joint management of marine mammals and a fish species. As an empirical case, we choose cod and grey seals in the Nordic-Baltic Sea countries, and several benefits and costs related to the latter are considered. We show that the optimal grey seal population is much lower than the actual population, and this result is robust to variations in relevant parameter values. This result can be explained by the fact that the profit from harvesting cod is much higher than the net benefits from grey seals.

中文翻译：

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海洋哺乳动物和鱼类的联合管理：以北欧-波罗的海国家的鳕鱼和灰海豹为例

在本文中，我们提出了一个简单的理论、稳态平衡、捕食者-猎物模型，用于海洋哺乳动物和鱼类的联合管理。作为一个经验案例，我们选择了北欧-波罗的海国家的鳕鱼和灰海豹，并考虑了与后者相关的一些收益和成本。我们表明，最佳灰海豹种群远低于实际种群，并且该结果对相关参数值的变化具有鲁棒性。这一结果可以解释为捕捞鳕鱼的利润远高于灰海豹的净收益。