Document Type

Thesis

Abstract

The severe decline of Crassostrea virginica populations along the Atlantic Coast of the United States since the 18" century is directly related to eutrophication from agricultural/industrial runoff and bottom-dredging from commercial fisheries. Previous research on C. virginica has focused mainly on modern and historical oyster populations already affected by humans, so little data on oyster populations exists before human impact. Examining multiple Pleistocene reefs in Virginia, North Carolina, and Maryland can provide scientists with data on a wide range of C. virginica populations that have not been influenced by human activity. Oyster samples collected from Wailes Bluff, Maryland; Cherry Point, Virginia; and Stetson Pit and Lee Creek, North Carolina have a mean shell height of 68.09 mm, and mean age of 1.91 years, and a mean growth rate of 38.96 mm/yr. The majority of the oysters in the sample were young, with very few oysters over the age of 3, which is comparable to modern oyster populations. The mean growth rate across all locations was much higher than the modern growth rate of 21.6 mm/yr though, which could be the result of different environmental conditions. Wailes Bluff, located at the mouth of the Potomac River, had the highest mean shell height and age (101.15 mm and 2.35 years). Stetson Pit was the most marine-influenced oyster sample and had the smallest mean shell height of 53.44 mm. Small seasonal bumps occurring on the oyster hinge are directly correlated with larger annual growth bumps, with a higher number of small bumps occurring before the first year of growth than after the first or second years of growth, which could be due to environmental factors such as mean temperature and salinity.

Date Awarded

2013

Department

Geology

Advisor 1

Rowan Lockwood

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