SS3.15 Physical Forcing and Pelagic-Benthic Interactions in Aquatic Systems
Date: Thursday, June 13, 2002
Time: 11:45:00 AM
Location: Oak Bay
RuesinkJL, University of Washington, Seattle, USA,
Roegner, C, , National Marine Fisheries Service, Astoria, USA,
Dumbauld, B, R, Washington Department of Fish and Wildlife, Nahcotta, USA,
Armstrong, D, , University of Washington, Seattle, USA,
We studied oyster (Crassostrea gigas) growth and recruitment to explore benthic-pelagic coupling in a west coast estuary. Juvenile oysters were transplanted to 10 sites in Willapa Bay, Washington, in arrays including four positions from shore and four tidal elevations. Growth was recorded after two months, along with natural recruitment. Oyster growth was highest at the estuary mouth, and within sites, growth increased with immersion time, except that oysters grown on-bottom had reduced growth. Spatial variation in growth was correlated with food (flourescence), and the importance of resource delivery was supported by bioenergetic modeling. Highest rates of secondary production near the estuary mouth corroborate recent findings that phytoplankton biomass in NE Pacific estuaries is strongly influenced by oceanic inputs, rather than by terrestrial sources or in situ production. Recruitment, in contrast, occurred primarily at the head of the bay, suggesting that circulation patterns along with larval behavior may reduce marine connections. Altogether, we found close relationships between water-column processes and the densities and productivity of a dominant benthic filter feeder.