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Size‐assortative Schooling in Free‐ranging Sticklebacks
Author(s) -
Peuhkuri Nina,
Ranta Esa,
Seppä Perttu
Publication year - 1997
Publication title -
ethology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.739
H-Index - 74
eISSN - 1439-0310
pISSN - 0179-1613
DOI - 10.1111/j.1439-0310.1997.tb00021.x
Subject(s) - gasterosteus , stickleback , foraging , fish <actinopterygii> , juvenile , biology , assortative mating , ecology , zoology , fishery , mating
Schooling behaviour is known to be advantageous for individual fish in many respects, including both foraging and predator avoidance. It has been repeatedly predicted by theory that to benefit most from schooling, individuals should associate together non‐randomly according to their phenotype. Obeying the predictions of theory, several fish species exhibit size‐assortative schooling in the laboratory, but unequivocal evidence for size‐assorted schools in the wild is largely lacking. To ascertain the existence of size‐assorted schools in the wild, we quantified the body‐size distribution of individuals in schools of wild threespine stickleback. Gasterosteus aculeatus , a species that is known to readily form size‐assorted schools under experimental conditions. Data were collected from 24 separate schools of juvenile fish in late summer 1994. The fish in those wild schools were size‐assorted, confirming the previous laboratory findings and, in accordance with current theory, suggesting that the phenotypic characteristics of individuals may be of importance when schools are formed.