title: Filtering impacts of larval and sessile zebra mussels (Dreissena polymorpha) in western Lake Erie.
abstract: We assessed the feeding biology of veliger larvae of the introduced zebra mussel (Dreissena polymorpha Pallas) in laboratory experiments using inert microspheres as food analogues. Mean clearance rate on 2.87-μm beads ranged between 247 and 420 μL veliger-1day-1. Clearance rate was unrelated to bead concentration up to 100 beads μL-1, but was positively correlated with veliger shell length. Clearance rates of Dreissena veligers are within the range of those reported for marine bivalve veligers of similar size and for herbivorous Great Lakes microzooplankton, but are orders of magnitude lower than those of settled, conspecific adults. The impact of settled zebra mussel grazing activities on phytoplankton stocks may be up to 1162 times greater than that exerted by veliger populations in western Lake Erie. Based on 1990 size-frequency distributions and associated literature-derived clearance rates, reef-associated Dreissena populations in western Lake Erie (mean depth ∼7 m) possess a tremendous potential to filter the water column (up to 132 m3m-2day-1) and redirect energy from pelagic to benthic foodwebs. Preliminary analyses indicate that chlorophyll a concentration is strongly depleted (<1 μg L-1) above Dreissena beds in western Lake Erie.
authors.affiliation: Department of Zoology, University of Toronto, Erindale College, L5L 1C6, Mississauga, Ontario, Canada.
authors.forename: Hugh J
authors.initials: HJ
authors.lastname: MacIsaac
authors.affiliation: Department of Zoology, University of Toronto, Erindale College, L5L 1C6, Mississauga, Ontario, Canada.
authors.forename: Gary
authors.initials: G
authors.lastname: Sprules
authors.affiliation: Department of Fisheries and Oceans, Great Lakes Laboratory for Fisheries and Aquatic Sciences, L7R 4A6, Burlington, Ontario, Canada.
authors.forename: Ora E
authors.initials: OE
authors.lastname: Johannson
authors.affiliation: Ontario Ministry of Natural Resources, Lake Erie Fisheries Station, R.R. #2, N0P 2P0, Wheatley, Ontario, Canada.
authors.forename: J H
authors.initials: JH
authors.lastname: Leach
keywords: Biological invasion; Clearance rate; Dreissena; Ecological impact; Lake Erie