HR: 11:30h
AN: NB42C-05 INVITED     [Abstracts]
TI: Hudson River Unionids and Zebra Mussels: The Beginning of the End or the End of the Beginning?
AU: * Strayer, D L
EM: strayerd@ecostudies.org
AF: Institute of Ecosystem Studies, P.O. Box AB, Millbrook, NY 12545 United States
AU: Malcom, H M
EM: malcomh@ecostudies.org
AF: Institute of Ecosystem Studies, P.O. Box AB, Millbrook, NY 12545 United States
AB: The invasion of the Hudson River estuary by zebra mussels was followed by steep declines (77 to >99.7%) in populations of all species of native bivalves between 1992 and 1999. Body condition of all unionids, and growth and recruitment of young unionids also declined significantly. Declines in population size and body condition were correlated primarily with the filtration rate of the zebra mussel population, not with fouling of native bivalves by zebra mussels. Samples taken since 2000, however, have shown that populations of all 4 common native bivalves have stabilized or even recovered, although the zebra mussel population has not declined. The mechanisms underlying this apparent reversal of fortune are not clear: recruitment and growth of young mussels have showed limited recovery, but body condition of adults has not. We found no evidence that spatial refuges contributed to this reversal of population declines. Simple statistical models project now that native bivalves may persist at population densities about an order of magnitude below their pre-invasion densities.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly