Data from: Density and group size influence shoal cohesion, but not coordination in zebrafish (Danio rerio)

The formations made by gregarious animals can range from loose aggregates to highly synchronized and ordered structures. For very large, coordinated groups, both physical and social environments are important for determining the physical arrangement of individuals in the group. Here we tested whether physical and social factors are also important in determining the structure of small, loosely coordinated groups of zebrafish. We found that even though our fish were not crowded and did not use most of the available space, the distance between individual fish was explained primarily by the amount of available space (i.e., density). Zebrafish in a larger space spread out more and the total dimensions of the shoal were an additive function also of group size. We, however, did not find any impact of social or physical environment on the orientation of individual fish or shoal. Thus, both physical and social factors were important for shoal spatial arrangements, but not individual orientation and shoal alignment.

群居动物所形成的群体结构，可覆盖从松散聚集到高度同步且有序的多种形态。针对规模庞大且协作紧密的群体，物理环境与社会环境均对群体内个体的空间排布具有关键作用。本研究探究了物理与社会因素是否同样会影响小型、松散协作的斑马鱼(Zebrafish)群体的结构。研究发现，即便实验所用的斑马鱼并未处于拥挤状态，且未占用全部可用空间，个体间的距离主要由可用空间总量（即密度）主导决定。处于更大空间中的斑马鱼分布更为分散，而鱼群(Shoal)的整体尺寸同时随群体规模呈累加性变化。但本研究未发现社会或物理环境对斑马鱼个体或鱼群的朝向存在任何显著影响。综上，物理与社会因素对鱼群的空间排布至关重要，但对个体朝向及鱼群整体的定向对齐并无显著作用。