Age, Growth, and Production of the Lake Sturgeon (Acipenser Fulvescens) in the Lake Winnebago Region, Wisconsin

Lake sturgeon populations, markedly reduced throughout most of their range, now support commercial or sport fisheries in few regions. A sport fishery in the Lake Winnebago area annually attracts approximately 2,000 spearers who take from about 400 to more than 2,800 fish. When spearing conditions are favorable more persons participate in the sport and enjoy a greater rate of success. The estimated catch of 2,828 lake sturgeon speared in 1953, weighing approximately 100,000 pounds, represented the largest catch on record. This annual yield of lake sturgeon is exceeded in North America only by commercial fisheries for white and green sturgeon in the States of Washington and Oregon. Lengths of lake sturgeon speared ranged from 30 to 79 inches; fish from 37 to 40 inches long were most abundant in the catch. Age determinations were accomplished by examining transverse sections of the marginal ray of the pectoral fin. Age-groups from 0 to LXXXII were represented in collections made in the Lake Winnebago area with age-groups XV to XXX most numerous. Growth in length is rather rapid during the first few years with the fish attaining the former legal size of 30 inches in about 7 years. A 40-inch sturgeon would be approximately 13 years old and a 50-inch fish, 20 years. No difference was noted in growth of the sexes. The length-weight relationship of lake sturgeon in the Lake Winnebago area was computed to be: log W = −4.17096 + 3.30367 log L, where W is weight in pounds and L is total length in inches. Female lake sturgeon live longer and thus grow to larger sizes than do the males. Females made up 96 percent of the total catch of fish over 60 inches long. Tendepedid larvae were the most important food item taken by the lake sturgeon in Lake Winnebago. In the smaller lakes, mayflies and aquatic sow bugs were also taken frequently.