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Diet composition and feeding periodicity of wild and hatchery subyearling Chinook salmon in Lake Ontario

Journal of Great Lakes Research

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DOI: 10.3394/0380-1330-34.4.590

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Abstract

Diel feeding periodicity, daily ration, and diet composition of wild and hatchery subyearling Chinook salmon Oncorhynchus tshawytscha were examined in Lake Ontario and the Salmon River, New York. The diet of wild riverine salmon was composed mainly of aquatic invertebrates (63.4%), mostly ephemeropterans (25.8%), chiromomids (15.8%), and trichopterans (8.3%). The diet of riverine Chinook was more closely associated with the composition of drift samples rather than bottom samples, suggesting mid-water feeding. In Lake Ontario terrestrial invertebrates were more important in the diet of hatchery Chinook (49.0%) than wild salmon (30.5%) and diet overlap between hatchery and wild salmon was low (0.46%). The diet of both hatchery and wild Chinook salmon was more closely associated with the composition of mid-water invertebrate samples rather than benthic core samples, indicating mid-water and surface feeding. Hatchery Chinook salmon consumed significantly less food (P < 0.05) than wild Chinook salmon in the lake and in the river, and wild salmon from Lake Ontario consumed more food than wild salmon in the Salmon River. Peak feeding of wild Chinook salmon occurred between 1200-1600 hours in Lake Ontario and between 1600-2000 hours in the Salmon River; there was no discernable feeding peak for the hatchery Chinook in Lake Ontario. Hatchery Chinook salmon also had the least diverse diet over the 24-hour sample period. These results suggest that at 7 days post-stocking hatchery Chinook salmon had not yet fully adapted to their new environment.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Diet composition and feeding periodicity of wild and hatchery subyearling Chinook salmon in Lake Ontario
Series title:
Journal of Great Lakes Research
DOI:
10.3394/0380-1330-34.4.590
Volume
34
Issue:
4
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Great Lakes Research
First page:
590
Last page:
598
Number of Pages:
9