Midwest Fish & Wildlife Conference 2016

AUTHORS: Edward A Baker*, Michigan Department of Natural Resources; Kim T. Scribner, Michigan State University

ABSTRACT: Stocking is increasingly being employed to rehabilitate and restore lake sturgeon Acipenser fulvescens populations around the Great Lakes and elsewhere. However, there is little information available to guide stocking decisions such as the appropriate number or age/size of fish to stock, post-stocking survival, etc. As part of ongoing evaluations of a long-term lake sturgeon restoration stocking program in Black Lake, Michigan, we conducted a gillnet survey in 2013 and employed a multiple-mark multiple-recapture population abundance estimator. We collected demographic data and determined fish age based on the presence and location of coded wire tags and pectoral fin-ray cross sections. We determined year-class specific abundance, overall survival from the year of stocking to 2013 for six cohorts, and year-class specific survival from age-0 to age-1 of stocked fish based on the known number stocked and compositional age estimates of the survey catch. Survival from year of stocking to 2013 ranged from 0.03-0.53 across the cohorts sampled. Assuming constant survival for age-1 and older fish, post-stocking survival from age-0 to age-1 ranged from 0.05-0.84 and increased with increasing size of fish at stocking. Based on stocked fish abundance and survival estimates, annual stocking targets for the Black Lake population were established to meet long-term management goals for adult abundance.