Growth of walleye (Stizostedion vitreum vitreum, Mitchill) in stormwater retention ponds and overwinter survival of stocked fry and fingerlings in two man-made lakes in Winnipeg, Manitoba
The walleye Stizostedion vitreum vitreum (Mitchill) , is the most economically important of Canada's inland fish species. Canadian commercial fisheries harvest several hundred metric tonnes of walleyes annually (Scott and Crossman 1979). Similarly, an angler survey in Ontario revealed that walleyes were the most commonly sought species and the second most abundant in angler's catches (Scott and Crossman 1979). Exploitation of this resource and habitat deterioration have, however, combined to reduce the quality of both commercial and angling fisheries in Dauphin Lake, Manitoba (Gaboury 1985). Statistics for the Dauphin Lake commercial fishery, available from the Manitoba Department of Natural Resources, Fisheries Branch, indicate a two to three fold drop in walleye catch for the period 1931-1975. In an attempt to enhance such walleye fisheries, walleye propagation has a history dating back to the late 1800's. Artificially propagated fry have been planted into lakes in Minnesota since 1887 (Smith and Moyle 1945). In Wisconsin, Wistrom (1957 ) estimates that a fry stocking program began as early as 1910 and that by 1937 over 839 million walleye fry were produced for stocking. These plants were often ineffective, and as a result pond reared fingerling production programs were undertaken in 1940 in both Minnesota (Smith and Moyle 1945) and Wisconsin (Wistrom 1957). Since then cultured fingerling walleyes have been planted into many waters with natural populations. Assessment of both fry and fingerling stocking has revealed varying degrees of success (Carlander et al. 1960; Schneider 1969; Jennings 1970; Klingbeil 1971; Kempinger and Churchill 1972; Forney 1975; Ward and Clayton 1975; Schweigert et al. 1977). Therefore, due to decreasing walleye stocks and in association with the Prairie Provinces Fishery Enhancement program, young of the year walleye fry were planted in two manmade lakes and two stormwater retention ponds in Winnipeg, Manitoba in 1982. The objectives of the research were: 1. To study the factors controlling growth and production in rearing ponds and, 2. To study the effects of time and size of transfers on subsequent survival in two man-made lakes. The first chapter deals with growth and production in rearing ponds and the second chapter concerns their subsequent survival after transfer into Fort Whyte Lakes 3 and 4.