Date Thesis Awarded
Bachelors of Science (BS)
Gregory M. Capelli
Randolph M. Chambers
I determined the occurrence and distribution of the Asian clam Corbicula fluminea in subtidal benthic habitats of the Mattaponi River estuary in southeastern Virginia. This work was completed in consideration of the effect of vegetation type on C. fluminea production. Hydrilla verticillata, a non-native species of SAV (submerged aquatic vegetation), has recently become the dominant species of SAV in the tidal freshwater reaches of the Chesapeake Bay. To date, no research has been done to evaluate the ecological value of H. verticillata or other tidal freshwater habitats of the Chesapeake Bay for macrobenthic invertebrate secondary production. If exotic H. verticillata beds alter macrobenthic production, then food webs and energy flow in the tidal freshwater regions of the estuary may also be affected. For this study, benthic samples were collected in June, July, and September 2009 at sites with H. verticillata or mixed vegetation (native and H. verticillata), as well as unvegetated sites in the tidal freshwater portion of the Mattaponi River, a sub-tributary of the York River Estuary. Preliminary analyses of data from June 2009 documented the occurrence of C. fluminea in benthic samples, and that the clam dominated total macroinvertebrate biomass. In August 2010 H. verticillata and unvegetated habitats were again sampled for C. fluminea. Daily production (mg AFDM m-2 d-1) of C. fluminea was compared among the three different habitats sampled in 2009 (unvegetated, H. verticillata dominated, and mixed vegetation) and two different habitats for 2010 (H. verticillata and unvegetated). Production was estimated for individual clams using an empirical method. Mean total production was computed per 5 mm length class, habitat type and month sampled. In 2009, the mixed and unvegetated samples exhibited greater levels of C. fluminea production than the samples 3 from the site with H. verticillata; however, this trend was not statistically significant. In 2010, there were no differences between the sampling sites in C. fluminea production. In addition to documenting for the first time the occurrence of C. fluminea in the Mattaponi River, the results of this study demonstrate that C. fluminea dominated macrobenthic secondary production (up to 300 mg AFDW m-1y-1) among three representative shallow subtidal habitats within the freshwater region of the Mattaponi River during 2009 and 2010. Relative to native or unvegetated benthic habitats, however, C. fluminea production was not affected by the presence of H. verticillata.
Wickel, Courtney, "Corbicula fluminea production in three major habitats, including one dominated by the non-native aquatic plant, Hydrilla verticillata, in the tidal freshwater Mattaponi River Estuary" (2011). Undergraduate Honors Theses. Paper 412.
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