Holubová Michaela, Čech Martin, Vašek Mojmír, Peterka Jiří
Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.
Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
PeerJ. 2019 Feb 4;7:e6378. doi: 10.7717/peerj.6378. eCollection 2019.
Grouping behaviour, as fascinating as it is unclear, has lately drawn the attention of numerous researchers. While most of the authors focused their work on a mechanistic approach to the matter of schooling, this study explores the issue from a population point of view. Present camera observation study on the fish community carried out in the epipelagic habitat of a European temperate reservoir in the Czech Republic explored the relationship between density and aggregative features of predominantly cyprinid fish stock. Results demonstrated that schooling behaviour is triggered by the 'critical density' of fish in the habitat. School size as well as counts of schools and proportion of schooling individuals increased with the density of fish. Counts of clusters (observed units in time, including singletons, pairs and schools) and cluster size, on the other hand, showed a slowing tendency to increase. The slower increase implies the tendency of fish for not being frequent but rather to create larger groups. Altogether, our findings suggest that fish density is a triggering factor in the formation of large fish schools. As the tendency of cyprinid species for school formation could be an evolutional advantage responsible for dominance in later succession phases of water bodies, we suggest that more in situ studies should be encouraged for the proper understanding of the ecological interactions that drive the structure of aquatic ecosystems and for ensuring unbiased assessment.
群体行为，尽管其本身令人着迷却又不甚明了，近来已吸引了众多研究人员的关注。虽然大多数作者将工作重点放在对鱼群行为机制的研究上，但本研究从种群角度探讨了这一问题。在捷克共和国一个欧洲温带水库的上层水域栖息地对鱼类群落进行的当前摄像观察研究，探究了以鲤科鱼类为主的鱼群密度与聚集特征之间的关系。结果表明，鱼群行为是由栖息地中鱼类的“临界密度”触发的。鱼群规模以及鱼群数量和群居个体的比例随鱼类密度的增加而增加。另一方面，集群数量（在特定时间观察到的单位，包括单独个体、成对个体和鱼群）和集群规模呈现出增长趋势变缓的情况。增长变缓意味着鱼类倾向于不频繁形成小群体，而是形成更大的群体。总体而言，我们的研究结果表明鱼类密度是大鱼群形成的触发因素。由于鲤科鱼类形成鱼群的倾向可能是一种进化优势，使其在水体后期演替阶段占据主导地位，我们建议应鼓励开展更多实地研究，以正确理解驱动水生生态系统结构的生态相互作用，并确保进行无偏评估。
