Raikow, D.F.
Presented at the ASM at Snowbird (2000-08-02 to 2017-12-05 )
Among the possible effects that the invasive zebra mussel (ZM) might have on the ecosystems of inland lakes is a detrimental impact on the larval stages of some fish due to competition for food. Larval bluegill (BG) are gape limited and rely on microzooplankton during the first weeks of life. Zebra mussels consume microzooplankton and have been shown to have a large impact on both the total biomass and relative abundance of zooplankton in systems other than inland lakes. To test whether and how zebra mussels might affect the growth of larval bluegill, a mesocosm experiment with three replicates of four treatments (ZM, BG, ZM + BG, and control) was conducted. Hatchling bluegill were collected from local lakes, reared in the lab, and upon reaching the swimming stage transferred to 1,500 L mesocosms. After two weeks the standard length of fish in the presence of zebra mussels was shorter: BG = 9.3 mm (SE= 0.15); BG + ZM = 8.4 (SE=0.02); separate variances t = -5.541, df = 2.1, p = 0.03. Zebra mussels increased transparency and reduced chlorophyll-a sestonic C and N, and particulate P.
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