Population dynamics of rainbow smelt (Osmerus mordax) in Lakes Ontario and Erie: a modeling analysis of cannibalism effects

Abstract

We used a stochastic stage-based matrix model (annual time step) and a bioenergetics model (daily time step) to simulate population dynamics, production, consumption, and conversion efficiency for rainbow smelt (Osmerus mordax) populations in Lakes Ontario and Erie. Cannibalism on young-of the-year (YOY) smelt by yearlings was the only scenario that reproduced alternate-year recruitment cycles observed in Lakes Ontario and Erie. Assuming constant survivorship and 5% variation in cannibalism, less than one YOY consumed per yearling smelt per year in both lakes could produce fluctuations greater than those observed. We found that at estimated daily mortality rates and during the pelagic phase of larvae only, 2% of the yearling smelt in Lake Erie and 5.1% in Lake Ontario need to consume one YOY per day to induce the observed abundance fluctuations. Bioenergetics simulations of alternating recruitment produced fluctuations in simulated values for annual gross production of approximately 6-7 and 31-59% for the Lake Ontario and Lake Erie smelt populations, respectively.