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Ontogeny of energy allocation reveals selective pressure promoting risk-taking behaviour in young fish cohorts

journal contribution
posted on 2005-07-22, 00:00 authored by Peter BiroPeter Biro, J Post, M Abrahams
Given limited food, prey fishes in a temperate climate must take risks to acquire sufficient reserves for winter and/or to outgrow vulnerability to predation. However, how can we distinguish which selective pressure promotes risk-taking when larger body size is always beneficial? To address this question, we examined patterns of energy allocation in populations of age-0 trout to determine if greater risk-taking corresponds with energy allocation to lipids or to somatic growth. Trout achieved maximum growth rates in all lakes and allocated nearly all of their acquired energy to somatic growth when small in early summer. However, trout in low-food lakes took greater risks to achieve this maximal growth, and therefore incurred high mortality. By late summer, age-0 trout allocated considerable energy to lipids and used previously risky habitats in all lakes. These results indicate that: (i) the size-dependent risk of predation (which is independent of behaviour) promotes risk-taking behaviour of age-0 trout to increase growth and minimize time spent in vulnerable sizes; and (ii) the physiology of energy allocation and behaviour interact to mediate growth/mortality trade-offs for young animals at risk of predation and starvation.

History

Journal

Royal society of London. Proceedings B. Biological sciences

Volume

272

Issue

1571

Pagination

1443 - 1448

Publisher

Royal Society Publishing

Location

London, England

ISSN

0962-8452

eISSN

1471-2954

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2005, The Royal Society