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Contribution and Relative Survival of Age‐0 Walleyes Stocked at Two Sizes in Six Eastern Ontario Lakes
Author(s) -
Pratt Thomas C.,
Fox Michael G.
Publication year - 2003
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/m01-185
Subject(s) - stocking , stizostedion , fishery , biology , fish <actinopterygii> , zoology
Size at stocking is believed to be a critical factor in determining the success of stocking events for many species. We examined the relative performance of summer (reared extensively, planted in June, average weight < 1 g) and fall (reared intensively, planted in September, average weight ∼ 10 g) walleye Stizostedion vitreum fingerlings stocked at a 5:1 summer‐to‐fall fingerling ratio into six small lakes in Eastern Ontario. One lake was stocked concurrently during 1990‐1993, and three lakes were given paired plants in 1992 and 1993; stocking assessments occurred at age 1 and as adults in 1997. Two additional lakes were stocked in 1998; in one the stocking failed, and in the other the stocking was assessed at age 1. Walleyes planted as summer fingerlings were significantly larger at first annulus formation than those planted as fall fingerlings, but these size differences disappeared in the adult fish recovered 4‐7 years after the paired plants. By the time the fish were adults, summer fingerlings were more abundant in the samples of all four lakes assessed to that stage. After accounting for the difference in stocking ratios, the relative survival to adulthood did not differ between the two fingerling types, except in Warrens Lake where summer fingerlings had a greater probability of survival. Given the relatively high cost of raising walleyes to the fall fingerling stage, we recommend that summer fingerlings be used when stocking walleyes into small, inland lakes.