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Alexandra Avila - Fish and Invertebrate Lab

Hood College, Fredrick, MD

Eastern oyster, Crassostrea virginica, spat: Factors affecting settlement and growth

Crassostrea virginica, the eastern oyster, is in trouble.  Its numbers have dwindled to a low of 26,000 bushels today from a high of 15 million bushels in the late 1800's. Factors responsible for this are over-harvesting especially as fishing gear efficiency improved; pollution and disease. Many organizations such as the Chesapeake Bay Foundation, local citizen groups and watermen are working hard to try and help restore the eastern oyster in the Bay. Despite years of time, money and effort towards restoration, the oyster population has seen little change. SERC has formed a partnership with these groups in order to bring a rigorous scientific perspective to this effort with applied scientific research.

My project consisted of determining optimal conditions for the settlement of oyster larvae into spat, for spat growth and for spat survival. At the SERC wet lab, four different tanks were set up to measure the effect of density, depth, and position on spat settlement and growth. As a result, we found out that spat growth is possibly affected by stock density and most likely by food availability and sunlight. We also concluded that in the SERC tanks, spat growth is not affected by depth of position. Also noted was the possibility that food availability is affected by spat density and by sunlight. One problem with this experiment is because of the lack of tank availability, density treatments could not be replicated.

Funding provided by the National Science Foundation - REU