Madison, Wisconsin: Wisconsin Department of Natural Resources
Summary
A sample of 161 female brown trout (Salmo trutta) from 8 central and northern Wisconsin streams were collected between 1966 and 1981 to determine age and size at maturity and length-fecundity relationships. The smallest mature female examined was 7.8 inches. Sexually mature females comprised 4% of the 7.0-7.9 inch size group, 27% of the 8.0-8.9 inch size group, 71% of the 9.0-9.9 inch size group, 92% of fish between 10-12.9 inches, and 100% of fish 13.0 inches and larger. No age I, 70% of age II, 95% of age III, and 100% of age IV and older trout were mature. Within a size group, more old females were sexually mature than young females.