Strains differences in the collective behaviour of zebrafish (Danio rerio) in heterogeneous environment

TL;DR

This study compares the collective behavior of two zebrafish strains in a heterogeneous environment, revealing differences in landmark preference, cohesion, and spatial distribution, highlighting the importance of strain variability in behavioral studies.

Contribution

It provides new insights into how different zebrafish strains exhibit distinct collective behaviors and responses to environmental cues, emphasizing the need to consider strain differences in behavioral research.

Findings

AB zebrafish spend more time near landmarks than TL zebrafish.

TL zebrafish exhibit higher group cohesion than AB.

Both strains transit between landmarks without long-term preference.

Abstract

Recent studies show differences in individual motion and shoaling tendency between strains of the same species. Here, we analyse the collective motion and the response to visual stimuli in two morphologically different strains (TL and AB) of zebrafish. For both strains, we observe 10 groups of 5 and 10 zebrafish swimming freely in a large experimental tank with two identical attractive landmarks (cylinders or disks) for one hour. We track the positions of the fish by an automated tracking method and compute several metrics at the group level. First, the probability of presence shows that both strains avoid free space and are more likely to swim in the vicinity of the walls of the tank and the attractive landmarks. Second, the analysis of landmarks occupancy shows that AB zebrafish are more present in their vicinity than TL zebrafish and that both strains regularly transit from one landmark to the other with no preference on the long duration. Finally, TL zebrafish show a higher cohesion than AB zebrafish. Thus, landmarks and duration of the repicates allow to reveal collective behavioural variabilities among different strains of zebrafish. These results provide a new insight into the need to take into account individual variability of zebrafish strains for studying collective behaviour.