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Lakewide estimates of alewife biomass and Chinook salmon abundance and consumption in Lake Ontario, 1989–2005: implications for prey fish sustainability

Transactions of the American Fisheries Society

By:
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DOI: 10.1577/T08-216.1

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Abstract

Stocking levels of Chinook salmon Oncorhynchus tshawytscha for Lake Ontario have been highly controversial since the early 1990s, largely because of uncertainties about lakewide abundance and rates of prey consumption. Previous estimates have focused on years before 1995; since then, however, the Lake Ontario ecosystem has undergone substantial changes, and there is new evidence of extensive natural recruitment. Presented here are new abundance estimates of Chinook salmon and alewives Alosa pseudoharengus in Lake Ontario and a reevaluation of the potential risk of alewife population collapse. We found that Lake Ontario has been supporting, on average (1989–2005), 1.83 × 106 (range, 1.08 × 106 to 3.24 × 106) Chinook salmon of ages 1–4, amounting to a mean annual biomass of 11.33 × 103 metric tons (range, 5.83 × 103 to 23.04 × 103 metric tons). During the same period (1989–2005), the lake supported an alewife biomass of 173.66 × 103 metric tons (range, 62.37 × 103 to 345.49 × 103 metric tons); Chinook salmon of ages 1–4 consumed, on average, 22% (range, 11–44%) of the alewife biomass annually. Because our estimates probably underestimate total consumption and because Chinook salmon are only one of several salmonine species that depend on alewives, predation pressure on the Lake Ontario alewife population may be high enough to raise concerns about long-term stability of this predator–prey system.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Lakewide estimates of alewife biomass and Chinook salmon abundance and consumption in Lake Ontario, 1989–2005: implications for prey fish sustainability
Series title:
Transactions of the American Fisheries Society
DOI:
10.1577/T08-216.1
Volume
139
Issue:
1
Year Published:
2010
Language:
English
Publisher:
Taylor & Francis Group
Publisher location:
London, UK
Contributing office(s):
Great Lakes Science Center
Description:
18 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Transactions of the American Fisheries Society
First page:
223
Last page:
240
Country:
United States
Other Geospatial:
Lake Ontario