Body length assortative shoaling in the European minnow, Phoxinus phoxinus

Citation
Ajw. Ward et J. Krause, Body length assortative shoaling in the European minnow, Phoxinus phoxinus, ANIM BEHAV, 62, 2001, pp. 617-621
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences","Neurosciences & Behavoir
Journal title
ANIMAL BEHAVIOUR
ISSN journal
0003-3472 → ACNP
Volume
62
Year of publication
2001
Part
4
Pages
617 - 621
Database
ISI
SICI code
0003-3472(200110)62:<617:BLASIT>2.0.ZU;2-J
Abstract
We investigated the functional aspects of active shoal choice behaviour and its role in generating body length assortative fish shoals. We presented s ingle European minnows with a choice between two conspecific shoals of equa l number, one of which consisted of fish of similar body length and the oth er of fish that were smaller or larger than the focal fish. The preference of the focal fish for the matched shoal increased with increasing differenc e in body length between itself and the unmatched shoal. To test a potentia l function of this, we used feeding trials to investigate the competitive a bility of a focal fish in a shoal of smaller or larger conspecifics. As bod y length differences between the focal fish and its shoalmates increased, t he focal fish took fewer prey items and took longer to take the first one. Collection of free-ranging fish shoals at the study site showed a within-sh oal variation of body length consistent with the preference behaviour obser ved in the laboratory. We discuss the importance of this work in the contex t of body length distributions in free-ranging shoals. (C) 2001 The Associa tion for the Study of Animal Behaviour.