DEVELOPMENT AND APPLICATION OF A BIOENERGETICS MODEL FOR JUVENILE WALLEYE POLLOCK

A bioenergetics model was parameterized for age-0 walleye pollock, The ragra chalcogramma, based on a synthesis of literature data. The sensi tivity of the new parameters was tested by individual parameter pertur bation (IPP) analysis. The model was applied to estimate individual an d total cohort food consumption of age-0 pollock in two areas of high pollock density in the Gulf of Alaska during the summer of 1990. Total cohort consumption was compared with zooplankton biomass and producti on estimates for the same areas and times of the year. The model was a lso used to examine the bioenergetic implications of age-0 pollock die l vertical migration through a thermal gradient. During a 1-month bioe nergetics simulation, individual daily consumption decreased from 16.0 to 6.0% of wet body weight. Daily ration estimates corresponded well with independent field estimates of daily ration for the same areas an d time of the year. Comparison of total cohort consumption with prey a vailability (production and biomass) indicated minimal potential for f ood limitation. Bioenergetic optimization of growth can be a potential benefit of diel vertical migration to age-0 pollock, however more inf ormation on prey density and distribution is needed to test this hypot hesis thoroughly. (C) 1998 The Fisheries Society of the British Isles.