Use of Oxytetracycline to Determine the Contribution of Stocked Fingerling Walleyes

Abstract

Fingerlings of walleye Stizostedion vitreum were marked by immersion in 200 mg oxytetracycline/L for 8.5 h before stocking in Mosquito Lake, Ohio. The marks were used to evaluate the contribution of the stocked fingerlings relative to natural reproduction. On average, 74 fingerlings were stocked per hectare during early June in 1988 and 1989. Mark retention over summer, assessed in a hatchery pond during 1988, was 100%. Marks were found on 73 and 65% of the age-0 Mosquito Lake walleye otoliths sampled in early October, 1988 and 1989, respectively. Because stocked fish contributed more than half to each walleye year-class, the continuation of annual walleye stocking in Mosquito Lake is recommended.