Krause J, Hoare D J, Croft D, Lawrence J, Ward A, Ruxton G D, Godin J G, James R
School of Biology, University of Leeds, UK.
Proc Biol Sci. 2000 Oct 7;267(1456):2011-7. doi: 10.1098/rspb.2000.1243.
Observations were made on three fish species (banded killifish (Fundulus diaphanus), golden shiner (Notemigonus crysoleucas) and white sucker (Catostomus commersoni)) in a temperate lake (New Brunswick, Canada) in order to investigate the relationship between shoal choice behaviour of individual fishes and shoal composition. Encounters between shoals were observed to take place every 1.1 min per shoal and an encounter lasted 3.7 s on average. The duration of shoal encounters was influenced by shoal size but not by differences between shoals in either body length or species. Conversely, the outcome of shoal encounters (i.e. ences between shoals in either body length or species. Conversely, the outcome of shoal encounters (i.e. whether or not an individual changes shoal) was influenced by body length and species differences but not by shoal size. Together, these results suggest that encounter duration itself is unlikely to have an important influence on encounter outcome. The collection of ten entire fish shoals showed that they were assorted by species and body length. A simulation model demonstrated that individual shoal choice behaviour alone could account for the generation and maintenance of the observed levels of size assortedness of shoals without invoking the existence of other sorting mechanisms such as differential swimming speeds. However, the generation of species assortedness was not predicted by the model. Furthermore, our data suggest that fish density acts as a constraint on shoal choice, influencing both shoal size and composition. This work has implications for studies on information transfer and reciprocal altruism within populations.
为了研究个体鱼类的鱼群选择行为与鱼群组成之间的关系，对加拿大新不伦瑞克省一个温带湖泊中的三种鱼类（带纹鳉鱼（Fundulus diaphanus）、金色闪光鱼（Notemigonus crysoleucas）和白亚口鱼（Catostomus commersoni））进行了观察。观察发现，鱼群之间的相遇平均每1.1分钟发生一次，每次相遇平均持续3.7秒。鱼群相遇的持续时间受鱼群大小的影响，但不受鱼群在体长或物种上差异的影响。相反，鱼群相遇的结果（即个体是否更换鱼群）受体长和物种差异的影响，但不受鱼群大小的影响。综合来看，这些结果表明相遇持续时间本身不太可能对相遇结果产生重要影响。收集的十个完整鱼群显示，它们按物种和体长进行了分类。一个模拟模型表明，仅个体的鱼群选择行为就可以解释观察到的鱼群大小分类水平的产生和维持，而无需调用其他分类机制，如不同的游泳速度。然而，该模型并未预测物种分类的产生。此外，我们的数据表明，鱼类密度对鱼群选择起到了限制作用，影响了鱼群的大小和组成。这项工作对种群内信息传递和互惠利他行为的研究具有启示意义。
