Survival and Growth of Intensively Reared Large Walleye Fingerlings and Extensively Reared Small Fingerlings Stocked Concurrently in Small Lakes

Abstract

Size of walleyes Stizostedion vitreum at the time of stocking is thought to play a key role in determining the success of stocking programs. Because starvation and predation risk are size-dependent processes, fingerlings stocked at larger sizes are expected to survive better than fingerlings stocked at smaller sizes. However, large fingerlings often require different culture techniques that make them more expensive to produce. Therefore, large fingerlings should only be used if returns are high enough to offset costs. We evaluated the relative success of two sizes of stocked walleye fingerlings in four lakes in New York State. For four consecutive years (1993–1996), each lake was stocked with equal densities (50 fish/ha) of small (30–50-mm), extensively reared pond fingerlings in June and large (120–140-mm), intensively reared fall fingerlings in September. In October, we electrofished each lake to determine growth and survival of stocked fingerlings. Despite being stocked at a much later date, average catch rates of fall fingerlings were not significantly higher than pond fingerlings. The relative survival of fingerlings varied among lakes, and in two lakes survival of fall fingerlings was actually lower than pond fingerlings. Similar patterns of survival were observed for walleyes caught as yearlings and for catches of older walleyes in gill nets. Fall fingerlings were also significantly smaller than pond fingerlings at the end of the first growing season, and this disparity persisted 3 years after stocking. Overall, our results indicate that relative success of the two sizes of stocked walleyes varies among lakes and that stocking large walleye fingerlings will not necessarily lead to higher returns.