Shoal size as a key determinant of vulnerability to capture under a simulated fishery scenario

Thambithurai, D., Hollins, J., Van Leeuwen, T., Rácz, A., Lindström, J. , Parsons, K. and Killen, S. S. (2018) Shoal size as a key determinant of vulnerability to capture under a simulated fishery scenario. Ecology and Evolution, 8(13), pp. 6505-6514. (doi: 10.1002/ece3.4107) (PMID:30038752) (PMCID:PMC6053581)

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Group living is widespread among animals and has a range of positive effects on individual foraging and predator avoidance. For fishes, capture by humans constitutes a major source of mortality, and the ecological effects of group living could carry‐over to harvest scenarios if fish are more likely to interact with fishing gears when in social groups. Furthermore, individual metabolic rate can affect both foraging requirements and social behaviors, and could, therefore, have an additional influence on which fish are most vulnerable to capture by fishing. Here, we studied whether social environment (i.e., social group size) and metabolic rate exert independent or interactive effects on the vulnerability of wild zebrafish (Danio rerio) to capture by a baited passive trap gear. Using video analysis, we observed the tendency for individual fish to enter a deployed trap when in different shoal sizes. Fish in larger groups were more vulnerable to capture than fish tested individually or at smaller group sizes. Specifically, focal fish in larger groups entered traps sooner, spent more total time within the trap, and were more likely to re‐enter the trap after an escape. Contrary to expectations, there was evidence that fish with a higher SMR took longer to enter traps, possibly due to a reduced tendency to follow groupmates or attraction to conspecifics already within the trap. Overall, however, social influences appeared to largely overwhelm any link between vulnerability and metabolic rate. The results suggest that group behavior, which in a natural predation setting is beneficial for avoiding predators, could be maladaptive under a trap harvest scenario and be an important mediator of which traits are under harvest associated selection.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Lindstrom, Dr Jan and Killen, Professor Shaun and Thambithurai, Davide and Hollins, Jack and Van Leeuwen, Dr Travis and Racz, Miss Anita and Parsons, Dr Kevin
Authors: Thambithurai, D., Hollins, J., Van Leeuwen, T., Rácz, A., Lindström, J., Parsons, K., and Killen, S. S.
College/School:College of Medical Veterinary and Life Sciences
Journal Name:Ecology and Evolution
ISSN (Online):2045-7758
Published Online:11 June 2018
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in Ecology and Evolution 8(13): 6505-6514
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
594261The Influence of Individual Physiology on Group Behaviour in Fish SchoolsShaun KillenNatural Environment Research Council (NERC)NE/J019100/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED