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Suppression of microzooplankton by zebra mussels: importance of mussel size
Author(s) -
MACISAAC HUGH J.,
LONNEE CHRISTOPHER J.,
LEACH J.H.
Publication year - 1995
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1995.tb00896.x
Subject(s) - dreissena , zebra mussel , copepod , biology , zooplankton , mussel , clearance rate , ecology , phytoplankton , bivalvia , veliger , rotifer , population , mollusca , zoology , fishery , crustacean , demography , sociology , nutrient , endocrinology
SUMMARY 1. The zebra mussel ( Dreissena polymorpha ) is amongst the most recent species to invade the Great Lakes. We explored the suppressive capabilities of mussels 6–22‐mm in size on Lake St Clair microzooplankton (< 240)μm) in laboratory experiments. 2. Absolute suppression of rotifers and Dreissena veliger larvae was proportional to mussel shell length for individuals larger than 10 mm; larger zooplankton, mainly copepod nauplii and Cladocera, were not affected. Mussel clearance rates on rotifers generally exceeded those on veligers, although rates for both increased with increasing mussel size. Rotifer‐based clearance rates of large (22 mm) mussels approached published values for phytoplankton food. 3. Most zooplankton taxa, particularly rotifers, declined significantly in western Lake Erie during the late 1980s concomitant with the establishment and population growth of zebra mussels in the basin. Densities of some taxa subsequently increased, although rotifers and copepod nauplii densities remained suppressed through 1993. Available evidence indicates that direct suppression by Dreissena coupled with food limitation provides the most parsimonious explanation for these patterns.