Growth and food consumption of vendace (Coregonus albula (L.)) in Lake Pyhäjärvi, SW Finland: a bioenergetics modeling analysis

We used a bioenergetics model to estimate daily food consumption of young-of-the-year (YOY) and adult vendace in the mesotrophic Lake Pyhajarvi. Weekly samples of fish and zooplankton, plus temperature data, were collected from May to October 1987, to describe the growth and diet of vendace. The estimates of population size were based on spring abundance of YOY and catch statistics. Information on the physiological energetics of vendace was derived from literature sources. The YOY showed steady growth throughout the summer, but the adults did not grow at all from late July to late August. The calculated daily food consumption of the vendace population was the highest in August. After mid-June, the YOY were the dominant consumers and were responsible for 83% of the cumulative food consumption of the whole vendace population in June–October. This consumption, 22 g wet mass m−2, was only 13% of the total crustacean zooplankton production, but about twice the production ofBosmina orEudiaptomus, the two most important single prey taxa. At certain times the food consumption of vendace was high enough to influence the population dynamics of its major prey species.