Population parameters and bioenergetic demands of walleye, Stizostedion vitreum vitreum (Mitchill), in relation to their trophic dynamic ecology, West Blue Lake, Manitoba

Abstract

During 1969-ZO, 569 walleye age II and older were marked in West Blue Lake of which 56 were recaptured. No short term mortality was found in conjunction with mark and release periods. As well, distribution of marked fish was essentially random, and similar segments (by age) of the population were under examination at all times. Frequency distributions and x2 tests indicate that net selection was not by age and unlikely to be by size. The May 1969 population, 1090 walleye, decreased to 819 individuals in May 19?0, but was augmented by 2100 Rew recruits in September, 1969, Petersen estimates, the Jolly (1965) approach, and the triple-catch trellis provided similar descriptions of the population. Mortality on a per day basis was small, mean i = 0.0045, and was greatest during fall and winter. Growth, and consequently production, was greatest between June and September. Biomass, approximately 800 kg, was stable from year to year, and. production, 34O kg, was primarily from younger fish... Walleye assimilation efficiency was dependent upon diet type (1east efficient for invertebrates, and most efficient for fish), and fish size. Maintenance per unit walleye was independent of size but was affected by temperature. Maintenance requirements, all converted to 20C for various age walleye approximates Winberg's (1956)... Laboratory conversion and assimilation efficiency was applied to the natural diet of walleye for an estimation of population intake. The resident population required from 40 to 1860 K cal/kg/day for production, and the intake depended upon season and population structure.