HR: 11:15h
AN: NB42C-04    [Abstracts]
TI: Are Predators Limiting Zebra Mussel Colonization of Unionid Mussels in Great Lake Coastal Wetlands?
AU: * de Szalay, F A
EM: ferenc@kent.edu
AF: Kent State University, Department of Biological Sciences, Kent, OH 44242 United States
AU: Bowers, R
EM: rbowers@edwards-pitman.com
AF: Edwards-Pitman Environmental, Inc., 1250 Winchester Parkway, Suite 200, Smyrna, GA 30080
AB: Although many native mollusc populations have been eliminated in the Laurentian Great Lakes by the exotic zebra mussel, recent surveys have found abundant unionid (Bivalvia: Unionidae) populations in some coastal wetlands. Unionid burrowing in soft sediments and predation by fish have been shown to reduce numbers of attached zebra mussels, and we tested these factors in a Lake Erie coastal wetland. In 2002, we held live unionids (Leptodea fragilis, Quadrula quadrula) and Pyganodon grandis shells in exclosures with wire mesh bottoms that were buried to sediment depths of either 5, 10, or 20 cm. After 2 months, numbers of attached dreissenids on unionids were significantly higher inside all exclosure treatments than outside exclosures. This indicated that either unionid burrowing was prevented in all sediment depth treatments or molluscivores were excluded by exclosures. In 2004, we measured dreissenid colonization on Q. quadrula and PVC plates in bottomless exclosures with different mesh sizes. After 6 months, dreissenid numbers on PVC plates and on Q. quadrula in 2.5 cm X 2.5 cm and 5 cm X 10 cm mesh exclosures were significantly higher than in open exclosures. These data suggest that molluscivores are important in limiting dreissenids in Great Lake coastal wetlands.
DE: 1890 Wetlands
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly