Diet of Juvenile Lake Trout in Southern Lake Ontario in Relation to Abundance and Size of Prey Fishes, 1979–1987
- 1 May 1991
- journal article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 120 (3) , 290-302
- https://doi.org/10.1577/1548-8659(1991)120<0290:dojlti>2.3.co;2
Abstract
We examined the diet of juvenile lake trout Salvelinus namaycush (<450 mm, total length) in Lake Ontario during four sampling periods (April–May, June, July–August, and October 1979–1987) in relation to changes in prey fish abundance in the depth zone where we caught the lake trout. Over all years combined, slimy sculpins Cottus cognatus contributed the most (39–52%) by wet weight to the diet, followed by alewives Alosa pseudoharengus (3–38%), rainbow smelt Osmerus mordax (17–43%), and johnny darters Etheostoma nigrum (2–10%). Over 90% of alewives eaten during April–May and June were age 1, and 98% of those eaten during October were age 0 (few alewives were eaten in July–August). Mean lengths of rainbow smelt and slimy sculpins in stomachs increased with size of lake trout. Juvenile lake trout generally fed opportunistically—seasonal and annual changes in diet usually reflected seasonal and annual changes in abundance of prey fishes near bottom where we captured the lake trout. Furthermore, diet ...Keywords
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