Relative importance of benthic and pelagic filter-feeders across a range of lake morphometry. Background:With both zooplankton and dreissenid mussels having a documented effect on water clarity through filter-feeding, we want to assess how the relative importance of these two groups is affected by season and by lake type. In estuarine systems, bivalves and other sessile filter-feeders are a major consumer of primary production. In lakes, the benthic filter feeders are not considered as important as zooplankton. This has changed with the arrival of dreissenid mussels.The relative importance of the two groups have to depend on lake morphometry and season. Zooplankton biomass change dramatically through the season, and so does their consumption. The spring clear water phase is due to the seasonal dynamics fast turnover organisms - algae and zooplankton. In contrast, mussels are long lived and their seasonal effect depend more on access to the water column, an access that change with stratification and decrease in summer. Their effect should be strongest during turnover. We have observed decreased spring blooms in our main study lake – Oneida Lake. Mussel effects should also be stronger in shallow and polymictic lakes than in stratified lakes. Finally, in lakes with deoxygenated hypolimnion, mussels will be restricted to the part of the bottom that has oxygen throughout the summer.We are looking for comparative data sets were both mussel and zooplankton data are available through at least one season. By combining such data sets with inferences from the GLM model on lake type, we hope to deduce the effect of lake type on the relative importance of the two filter-feeding groups.