Biology Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2749

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    The effect of aquaculture gear and tidal zone on the growth and shape of the oyster Crassostrea virginica during a “finishing period” in Chesapeake Bay.
    (2016) Thomas, Laura Landis; Plough, Louis V; Cornwell, Jeffrey C; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study investigated how aquaculture gear type and increased wave action influenced growth and shape of eastern oysters Crassostrea virginica during a “finishing” period in Chesapeake Bay. Oysters were deployed in three different gear treatments in the intertidal or upper water column: bottom cages, OysterGro™ floats, and rack and bag, and a bottom cage was also deployed in the subtidal zone as an industry control. Shell length(L), width(W), height(H), total weight and wet meat weight were measured each month from August to December 2015 and an index of shell shape (deviation of L-W-H from idealized 3-2-1 ratio) calculated. OysterGro™ floats produced the greatest increase in wet and total weight and the most ideal shaped oysters (lowest 3-2-1 ratio deviation). Overall, these results demonstrate the benefit of deploying oysters in higher wave action gear types such as the OysterGro™ and will increase the available data on gear performance in Chesapeake Bay.
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    DEVELOPING SPATIALLY-EXPLICIT ASSESSMENT TOOLS FOR EASTERN OYSTER IN CHESAPEAKE BAY
    (2011) Livings, Maude Elizabeth; Wilberg, Michael J; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Decreasing abundance of the eastern oyster Crassostrea virginica in Chesapeake Bay is of concern because of its ecological, economic, and cultural importance. The objective of my study was to develop methods for conducting stock assessments of eastern oysters in Maryland waters of Chesapeake Bay that estimate abundance, recruitment, and fishing mortality at regional scales. First, I evaluated how spatial patterns in autocorrelation of recruitment and adult relativity density varied over time by fitting semivariogram models to survey data for each year. This information was then used to determine appropriate scales for my second objective which was to develop a stage-based model for the lower Potomac River using data from the Maryland Department of Natural Resources fall dredge survey and fishery data from the Potomac River Fisheries Commission. Estimated abundance declined to approximately 39% of that in 1990. The analyses will provide a platform for regional management of eastern oysters.