Evaluation of Walleye Stocking in Two Large Missouri Reservoirs

摘要

Walleyes Sander vitreus are commonly stocked into reservoirs across North America, but success of these stockings has been variable, and few stockings have been thoroughly evaluated. We examined six factors that may affect survival of small walleye fmgerlings (25—50 mm total length) stocked into two large Missouri reservoirs: (l) initial health of stocked fish, (2) handling and transportation stress, (3) water temperature in transport and receiving waters, (4) prey abundance in receiving waters, (5)losses from predation, and (6) growth of stocked fish. Fin-gerlings were marked with oxytetracycline hydrochloride and stocked into Smith-ville and Stockton lakes in alternate years from 1998 to 2006, usually at a rate of 70-80 fish/ha. None of the measured survival factors was related to a relative survival index (ratio of the number of age-0 captured/h of October electrofishing to the number stocked/ha). We also assessed whether stockings increased age-0 and adult abundance and angler catch and harvest of walleyes. For stocking years, , the majority of age-0 walleyes collected in October originated from stocking for both Smithville (63-100% marked, mean = 91%) and Stockton (62-100% marked, mean = 88%) lakes. Electrofishing catch of age-0 walleyes inOctober was higher in stocking than in nonstocking years. Following stocking, adult abundance and angler catch and harvest of walleyes increased. Fingerling stockings improved the sport fishery for walleyes in both lakes. However, stocking will have tocontinue to maintain the fisheries because natural recruitment of walleyes did not increase as a result of increased adult abundance.