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Fisheries Behavioral Ecology - Abstracts

Ryer, C.H. and B.L. Olla. 1995. Influences of food distribution on fish foraging behaviour. Animal Behaviour 49:411-418.


Juvenile walleye pollock, Theragra chalcogramma, use group foraging, mediated by local enhancement, when searching for prey that are clumped in time and space. Local enhancement occurs when fish are attracted to the site where another fish has discovered food. Experiments were conducted to determine whether fish forage as individuals when food is widely dispersed in time and space. When acclimatized to dispersed food, juvenile walleye pollock foraged as individuals and did not respond to the food discovery of others. Some fish appeared to aggressively defend areas of their tank, a behaviour not seen in fish foraging for clumped food. In a second experiment, examining the role of prior experience in fish foraging, fish were first acclimatized to clumped food and then suddenly switched to dispersed food. Fish continued to use group foraging, mediated by local enhancement, with no change over 20 food discovery events. These results indicate that social aspects of fish foraging strategies are flexible, but are also influenced by prior experience with resource distribution.


Last updated 31 March, 2009

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