We examined the effects of rearing method and size at stocking on the survival of muskellunge Esox masquinongy in Chautauqua Lake, New York. Since 1961, changes in rearing methods have coincided with declining abundance of adult muskellunge. In particular, a change from pond rearing to trough rearing coincided with declining catches of adult muskellunge in pound nets. The decline was only partly reversed by changes from trough rearing to pond finishing of fingerlings. Changes in survival to age 5 from 1961 to 1996 indicated that both rearing method and stocking length significantly affected survival. Greater length at stocking resulted in higher survival rates. After accounting for length at stocking, survival was highest for pond‐reared fingerlings, intermediate for pond‐finished fingerlings, and lowest for trough‐reared fingerlings. A modified Ricker stock–recruitment model indicated that survival of fingerlings declined over time. Increases in the adult stock of walleye Stizostedion vitrium since the 1960s may have increased predatory pressure on fingerlings and increased the importance of greater length at stocking.
Black crappies Pomoxis nigromaculatus and white crappies P. annularis were introduced to Chautauqua Lake from Sodus Bay of Lake Ontario (New York) in the late 1920s to establish a recreational fishery. The abundance of both species rapidly increased, and an intensive recreational fishery developed. Anecdotal accounts from the recreational fishery and catches in pound nets indicate that both species remained at high levels of abundance until the 1970s. However, the catch of age‐2 crappies in gill‐net samples has declined since 1978. Index trawling from 1978 to 1999 indicated that the year‐class strength of black and white crappies was synchronized and fixed between fall of age 0 and fall of age 1. Age‐0 crappie abundance was positively associated with the biomass of walleye prey (yellow perch Perca flavescens, sunfish Lepomis spp., and white perch Morone americana) and negatively associated with that of walleye Stizostedion vitreum, showing that availability of alternative prey affects walleye predation on crappies. The mortality of crappies from fall of age 0 to fall of age 1 was not related to winter severity, predation, or prey abundance. Low abundance of age‐2 crappies and the lack of any significant relation between the adult stock and age‐0 abundance showed that the recreational fishery or transfers of adult crappies from Chautauqua Lake were unlikely causes for poor recruitment to the crappie populations.
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