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Group foraging by a stream minnow: shoals or aggregations?

Animal Behaviour

By:
and
DOI: 10.1016/0003-3472(92)90050-J

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Abstract

The importance of social attraction in the formation of foraging groups was examined for a stream-dwelling cyprinid, the rosyside dace, Clinostomus funduloides. Dace arrivals and departures at natural foraging sites were monitored and tested for (1) tendency of dace to travel in groups, and (2) dependency of arrival and departure rates on group size. Dace usually entered and departed foraging sites independently of each other. Group size usually affected neither arrival rate nor departure probability. Thus, attraction among dace appeared weak; foraging groups most often resulted from dace aggregating in preferred foraging sites. The strongest evidence of social attraction was during autumn, when dace departure probability often decreased with increasing group size, possibly in response to increased threat of predation by a seasonally occurring predator. Dace also rarely avoided conspecifics, except when an aggressive individual defended a foraging site. Otherwise, there was little evidence of exploitative competition among dace for drifting prey or of foraging benefits in groups, because group size usually did not affect individual feeding rates. These results suggest that the benefits of group foraging demonstrated under laboratory conditions in other studies may not always apply to field conditions.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Group foraging by a stream minnow: shoals or aggregations?
Series title:
Animal Behaviour
DOI:
10.1016/0003-3472(92)90050-J
Volume
44
Issue:
3
Year Published:
1992
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
393-403
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Animal Behaviour
First page:
393
Last page:
403
Number of Pages:
11