Effect of aquatic macrophyte cover and fetch on spatial variability in the biomass and growth of littoral fishes in bays of Prince Edward County, Lake Ontario

Biomass and growth of Pumpkinseed ( Lepomis gibbosus), Yellow Perch ( Perca flavescens) and cohabiting species varied among different bays of Prince Edward County in eastern Lake Ontario. Biomass (B) and a calculated fish production (P) index of fishes, estimated as the product of average seasonal biomass and P/B, was about 6x higher at the electrofishing transects with medium to high macrophyte cover and low fetch than at sites where macrophytes were absent or sparse and fetch was high. The production index -aquatic plant relationship was species-dependent. The biomass component of fish production was related to macrophyte cover but the growth component and P/B (determined by allometry with body size) was not. Biomass and inferred production could be predicted from fetch, macrophyte abundance and water temperature, but with low precision. Results were consistent with index trawling in showing that changes in aquatic vegetation following Dreissena colonization in the Bay of Quinte and vicinity have affect...