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The influence of species composition on behaviour in mixed‐species cyprinid shoals
Author(s) -
Allan J. R.
Publication year - 1986
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1986.tb05002.x
Subject(s) - shoal , biology , cyprinidae , competition (biology) , ecology , fishery , fish <actinopterygii> , oceanography , geology
Adult dace, minnows and gudgeon (50 of each) were studied in a fluvarium. Each possible paired‐and three‐species combination was compared with single‐species controls. Species position in the fluvarium and the behaviour of marked individuals were used to measure interactions. Individual behaviours were standardized for day‐to‐day changes in activity level. The presence of a second species caused significant increases in the frequency and total time of behaviours associated with positional change. Such behavioural changes may reduce competition by adjusting individual position within the shoal. Minnows moved higher in the water and downstream in the presence of dace. Gudgeon moved lower in the water and downstream in the presence of dace and of minnows. Dace made slight, but significant, movements downstream and higher in the water column in response to both minnows and gudgeon. These shifts were very distinct, and the resulting shoal structure mirrors the positions occupied in mixed‐species shoals of these species in the wild.