We used long-term data on Oneida Lake, New York, to evaluate hypotheses about the effects of introduced zebra mussels (Dreissena polymorpha) on yellow perch (Perca flavescens). We detected no change in survival, diet, or numbers of young-of-the-year (YOY) yellow perch. YOY growth increased in association with zebra mussel introduction and was marginally correlated with zooplankton size, which increased after zebra mussel introduction. Low numbers of YOY in recent years did not explain their increased growth rate. The percentage of age 3 and older yellow perch that consumed zooplankton and benthos increased after zebra mussel introduction. Water clarity, which has increased since zebra mussel introduction, was inversely related to the percentage of the adult population with empty stomachs and positively related to the percentage that consumed benthos. The percentage of adult yellow perch that consumed zooplankton was positively related to zooplankton size. Despite the increase in percentage of adults consuming both types of invertebrate prey, we detected no changes in adult growth associated with zebra mussel introduction. This suggests that the principal effects of zebra mussels on yellow perch in Oneida Lake were not via benthic pathways but through modifications of water clarity and zooplankton. Thus far, these effects have not been negative for the yellow perch population.
Will the Displacement of Zebra Mussels by Quagga Mussels Increase Water Clarity in Shallow Lakes during Summer? Results from a Mesocosm Experiment