The Smallmouth Bass Population and Fishery in a Northern Wisconsin Lake, with Implications for other Waters

Smallmouth bass (Micropterus dolomieui) were captured in fyke nets and tagged in Clear Lake (342 hectares), Oneida County, Wisconsin, and a creel survey of the sport fishery was conducted. The population, as indicated from catches in the nets and by anglers, was composed mainly of young, small fish; more than 95% were of ages I‐IV and less than 300 mm long. Their growth in this oligotrophic lake was slower than that in most other waters, and estimated production per unit recruitment, 1,265 g per 1,000 g, was less than in some other populations. Estimated annual fishing, natural, and total mortality rates were 56, 49, and 77.5%. The mean population estimate for smallmouth bass over 225 mm long was 8.7 fish per hectare, estimated fishing pressure was 36‐49 hours per hectare, the catch rate averaged 6 smallmouth bass per 100 hours of effort, and the harvest (estimated in two ways) was 2.1 and 3.8 fish per hectare. Calculation of equilibrium yield per unit recruitment indicated that reducing fishing mortality with minimum length limits of 240, 297, 322, and 354 mm would increase the weight harvested by 6, 13.5, 13.8, and 14.4% over that under a no‐limit regulation. Length regulations probably would benefit other inland smallmouth bass fisheries, many of which appear to have populations with mortality rates, catch rates, and size and age structures similar to those of the population in Clear Lake.