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Density, aggregation, and body size of northern pikeminnow preying on juvenile salmonids in a large river

Journal of Fish Biology

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DOI: 10.1006/jfbi.2000.1524

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Abstract

Predation by northern pikeminnow Ptychocheilus oregonensis on juvenile salmonids Oncorhynchus spp. occurred probably during brief feeding bouts since diets were either dominated by salmonids (>80% by weight), or contained other prey types and few salmonids (<5%). In samples where salmonids had been consumed, large rather than small predators were more likely to have captured salmonids. Transects with higher catch-per-unit of effort of predators also had higher incidences of salmonids in predator guts. Predators in two of three reservoir areas were distributed more contagiously if they had preyed recently on salmonids. Spatial and temporal patchiness of salmonid prey may be generating differences in local density, aggregation, and body size of their predators in this large river.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Density, aggregation, and body size of northern pikeminnow preying on juvenile salmonids in a large river
Series title:
Journal of Fish Biology
DOI:
10.1006/jfbi.2000.1524
Volume
58
Issue:
4
Year Published:
2001
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Fish Biology
First page:
1137
Last page:
1148
Number of Pages:
12