Some Aspects of the Organization of Fish Schools

Publisher Website
Google Scholar
Abstract
The objective of this study was to describe the organization of schools of the pelagic marine fishes Scomber japonicus, Trachurus symmetricus, Engraulis mordax, Atherinopsis californiensis, and Atherinops affinis. Organization was studied in larval through adult stages by analysis of spatial and angular relations among fish in dorsal photographs of schools.In all species, schools of young fish, larval and juveniles, were typically less compact and showed greater differences in angular headings than did schools of adult fish. The rate at which school structure changed with size varied among species; it was rapid in Scomber and the atherinids and slower in Engraulis and Trachurus. School organization differed among species at the adult stage. Schools of Scomber were typically the most compact and organized; Trachurus and Engraulis schools were intermediate in their organization and Atherinops schools were the least organized.Spatial and angular measurements were also used to develop inferences regarding the "following reaction" in four of the species. The similarity in angular headings between fish was used as the criterion of following. These analyses showed that the similarities in headings between two fish in a school decreased with the distance they were apart. The headings most alike between adjacent fish in a school were between those in file. These results suggested that the neighbor directly ahead of a given fish in a school is used more frequently as an angular reference for the following reaction than ones to the side.Analysis of the distances between neighbors in the four species indicated that fish were closer to adjacent neighbors in the file than they were to ones in rank. This suggested that spacing in the horizontal plane might be related to tail movement.

This publication has 1 reference indexed in Scilit: