Abstract Classical fisheries biology aims to optimise fisheries-level outcomes, such as yield or profit, by controlling the fishing effort. This can be adjusted to allow for the effects of environmental stochasticity, or noise, in the population dynamics. However, when multiple fishing entities, which could represent countries, commercial organisations, or individual vessels, can autonomously determine their own fishing effort, the the optimal action for one fishing entity depends on the actions of others. Coupled with noise in the population dynamics, and with decisions about fishing effort made repeatedly, this becomes an iterated stochastic game. We tackle this problem using the tools of stochastic optimisation, first for the monopolist’s problem and then for the duopolist’s problem. In each case, we derive optimal policies that specify the best level of fishing effort for a given stock biomass. Under these optimal policies, we can calculate the equilibrium stock biomass, the expected long-term return from fishing and the probability of stock collapse. We also show that there is a threshold stock biomass below which it is optimal to stop fishing until the stock recovers. We then develop an agent-based model to test the effectiveness of simple strategies for responding to deviations by an opponent from a cooperative fishing level. Our results show that the economic value of the fishery to a monopolist, or to a consortium of fishing agents, is robust to a certain level of noise. However, without the means of making agreements about fishing effort, even low levels of noise make sustained cooperation between autonomous fishing agents difficult.

中文翻译：

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具有环境随机性的共同可再生资源开发中的合作与非合作行为

摘要 经典渔业生物学旨在通过控制捕捞努力来优化渔业层面的结果，例如产量或利润。这可以进行调整，以考虑到种群动态中的环境随机性或噪声的影响。然而，当代表国家、商业组织或个别船只的多个捕捞实体可以自主决定自己的捕捞努力时，一个捕捞实体的最佳行动取决于其他捕捞实体的行动。再加上种群动态中的噪音，以及反复做出的捕捞努力决策，这成为一个迭代的随机博弈。我们使用随机优化工具来解决这个问题，首先针对垄断者的问题，然后针对双头垄断者的问题。在每种情况下，我们推导出最佳政策，指定给定种群生物量的最佳捕捞努力水平。在这些最优策略下，我们可以计算平衡种群生物量、渔业的预期长期收益和种群崩溃的概率。我们还表明，存在一个阈值种群生物量，低于该阈值是停止捕捞直至种群恢复的最佳选择。然后我们开发了一个基于代理的模型来测试简单策略的有效性，以响应对手从合作捕鱼水平的偏差。我们的结果表明，渔业对垄断者或渔业代理财团的经济价值在一定水平的噪音下是稳健的。然而，如果没有就捕捞努力达成一致的手段，即使是低水平的噪音也会使自主捕捞代理之间的持续合作变得困难。