Comparative Survival and Growth of Planted Wild, Hybrid, and Domestic Strains of Brook Trout (Salvelinus fontinalis) in Ontario Lakes

Abstract

Matched plantings of domestic strain and interstrain hybrid (or wild strain) brook trout (Salvelinus fontinalis) were made annually in nine small Precambrian Shield lakes during 1973–77. Recoveries of planted fish were made by gillnetting and/or angling during 1974–80. In six study lakes, hybrids (and wild strains) were recovered at rates two to four times greater than the domestic strain; in three lakes recoveries were similar. Most domestic strain trout were caught in the year following planting whereas recoveries of hybrids and wild strains were spread over 3–4 yr. Each kilogram of hybrid (or wild) planted yielded 5.6 kg (1.2–12.3); each kilogram of domestic strain planted yielded 0.8 kg (0.2–2.1). Lakes containing only minnows and sticklebacks yielded the highest returns of brook trout; lakes containing competitive species yielded low returns. Rapid growth of brook trout occurred in lakes containing only minnows and sticklebacks; slowest growth was noted in lakes supporting white suckers (Catostomus commersoni). Domestic strain brook trout and the matched hybrid grew at approximately the same rate within a lake and in seven of the nine lakes ate the same food. The performance of the Nipigon × domestic hybrid qualifies it for consideration as a replacement for the domestic brook trout presently planted in Ontario lakes.Key words: planting, brook trout, trout strain, hybrid, Precambrian Shield, survival, stock