Impact of forest harvesting on larval and juvenile growth of yellow perch (Perca flavescens) in boreal lakes

Any factor modifying early growth in fishes could lead to large recruitment variations. We investigated the impact of forest harvesting on growth rate and length-at-age of larval and juvenile yellow perch (Perca flavescens) and on the trophodynamics in small oligotrophic Canadian Boreal Shield lakes. Yellow perch, phytoplankton, and zooplankton were sampled in August or early September in three consecutive years (2003, 2004 and 2005) from three unperturbed lakes and from three lakes that had had logging in their watershed catchment zones after the first year of sampling. Two years after the perturbation, larval and juvenile growth rate and length-at-age of yellow perch, as well as Chl a, were significantly higher in lakes perturbed by forest harvesting than in unperturbed ones. Our results support the hypothesis that early growth of yellow perch has been favoured in perturbed lakes. This may have been due to post-harvest enhancements in nutrients and dissolved organic carbon concentrations, likely generating bottom-up changes in larval and juvenile yellow perch feeding conditions such as increased prey abundance and visibility thus, stimulating growth.