We analyse the dynamics of fishing vessels with different home ports in an area where these vessels, in choosing where to fish, are influenced by their own experience in the past and by their current observation of the locations of other vessels in the fleet. Empirical data from the boats near Ancona and Pescara shows stylized statistical properties that are reminiscent of Kirman and Föllmer’s ant recruitment model, although with two ant colonies represented by the two ports. From the point of view of a fisherman, the two fishing areas are not equally attractive, and he tends to prefer the one closer to where he is based. This piece of evidence led us to extend the original ants model to a situation with two asymmetric zones and finite resources. We show that, in the mean-field regime, our model exhibits the same properties as the empirical data. We obtain a phase diagram that separates high and low herding regimes, but also fish population extinction. Our analysis has interesting policy implications for the ecology of fishing areas. It also suggests that herding behaviour here, just as in financial markets, will lead to significant fluctuations in the amount of fish landed, as the boat concentration on one area at a given point in time will diminish the overall catch, such loss not being compensated by the reproduction of fish in the other area. In other terms, individually rational behaviour will not lead to collectively optimal results.

我们分析了在一个区域内拥有不同母港的渔船的动态，这些渔船在选择在哪里捕鱼时受到他们过去的经验和他们目前对船队中其他船只位置的观察的影响。来自 Ancona 和 Pescara 附近船只的经验数据显示了程式化的统计特性，让人想起 Kirman 和 Föllmer 的蚂蚁招募模型，尽管两个港口代表了两个蚁群。从渔民的角度来看，这两个钓鱼区的吸引力并不相同，他往往更喜欢离自己所在地较近的一个。这条证据使我们将原始蚂蚁模型扩展到具有两个不对称区域和有限资源的情况。我们表明，在平均场范围内，我们的模型表现出与经验数据相同的属性。我们获得了一个相图，它将高和低放牧制度以及鱼类种群灭绝分开。我们的分析对渔区生态具有有趣的政策意义。它还表明，这里的放牧行为，就像金融市场一样，将导致上岸鱼量的显着波动，因为在给定时间点集中在一个区域的船只会减少总捕捞量，这种损失没有得到补偿通过其他地区的鱼类繁殖。换句话说，个人理性的行为不会导致集体最优的结果。就像在金融市场中一样，这将导致上岸鱼量的显着波动，因为在给定时间点船只集中在一个区域会减少总捕获量，这种损失无法通过另一个区域的鱼类繁殖来补偿区域。换句话说，个人理性的行为不会导致集体最优的结果。就像在金融市场中一样，这将导致上岸鱼量的显着波动，因为在给定时间点船只集中在一个区域会减少总捕获量，这种损失无法通过另一个区域的鱼类繁殖来补偿区域。换句话说，个人理性的行为不会导致集体最优的结果。