Collective gradient sensing in fish schools

TL;DR

This study investigates how fish schools navigate noisy environments by balancing social cues and environmental sensing, revealing species differences and the importance of information weighting for optimal group behavior.

Contribution

It provides experimental evidence of collective gradient sensing in fish and explores how social and environmental information integration affects group performance.

Findings

Rummy nose tetras outperform golden shiners in gradient sensing.

Group performance depends on the balance of social and environmental information.

Optimal group morphology arises from proper weighting of social and environmental cues.

Abstract

Throughout the animal kingdom, animals frequently benefit from living in groups. Models of collective behaviour show that simple local interactions are sufficient to generate group morphologies found in nature (swarms, flocks and mills). However, individuals also interact with the complex noisy environment in which they live. In this work, we experimentally investigate the group performance in navigating a noisy light gradient of two unrelated freshwater species: golden shiners (Notemigonus crysoleucas) and rummy nose tetra (Hemigrammus bleheri). We find that tetras outperform shiners due to their innate individual ability to sense the environmental gradient. Using numerical simulations, we examine how group performance depends on the relative weight of social and environmental information. Our results highlight the importance of balancing of social and environmental information to promote optimal group morphologies and performance.