Fish swimming in schools save energy regardless of their spatial position

Marras, S., Killen, S. S. , Lindström, J. , McKenzie, D. J., Steffensen, J. F. and Domenici, P. (2014) Fish swimming in schools save energy regardless of their spatial position. Behavioral Ecology and Sociobiology, 69(2), pp. 219-226. (doi: 10.1007/s00265-014-1834-4) (PMID:25620833) (PMCID:PMC4293471)

Abstract

For animals, being a member of a group provides various advantages, such as reduced vulnerability to predators, increased foraging opportunities and reduced energetic costs of locomotion. In moving groups such as fish schools, there are benefits of group membership for trailing individuals, who can reduce the cost of movement by exploiting the flow patterns generated by the individuals swimming ahead of them. However, whether positions relative to the closest neighbours (e.g. ahead, sided by side or behind) modulate the individual energetic cost of swimming is still unknown. Here, we addressed these questions in grey mullet Liza aurata by measuring tail-beat frequency and amplitude of 15 focal fish, swimming in separate schools, while swimming in isolation and in various positions relative to their closest neighbours, at three speeds. Our results demonstrate that, in a fish school, individuals in any position have reduced costs of swimming, compared to when they swim at the same speed but alone. Although fish swimming behind their neighbours save the most energy, even fish swimming ahead of their nearest neighbour were able to gain a net energetic benefit over swimming in isolation, including those swimming at the front of a school. Interestingly, this energetic saving was greatest at the lowest swimming speed measured in our study. Because any member of a school gains an energetic benefit compared to swimming alone, we suggest that the benefits of membership in moving groups may be more strongly linked to reducing the costs of locomotion than previously appreciated.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lindstrom, Dr Jan and Killen, Professor Shaun
• Authors: Marras, S., Killen, S. S., Lindström, J., McKenzie, D. J., Steffensen, J. F., and Domenici, P.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Behavioral Ecology and Sociobiology
• Publisher: Springer Berlin Heidelberg
• ISSN: 0340-5443
• ISSN (Online): 1432-0762
• Copyright Holders: Copyright © 2014 Springer-Verlag Berlin Heidelberg
• First Published: First published in Behavioral Ecology and Sociobiology 2014
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
59426	1	The Influence of Individual Physiology on Group Behaviour in Fish Schools	Shaun Killen	Natural Environment Research Council (NERC)	NE/J019100/1	RI BIODIVERSITY ANIMAL HEALTH & COMPMED