Defense Date

3-25-2019

Document Type

Capstone

Degree Name

M.S. Coastal Zone Management

First Advisor

Joana Figueiredo, Ph.D.

Second Advisor

Bernhard Riegl, Ph.D.

Abstract

Populations of Crassostrea virginica, the Eastern oyster, have been declining since the late 1800s. While overharvesting is the primary cause of decline, the Eastern oyster is also facing the threat of disease and habitat loss. As oyster populations decline, habitat suitable for oyster spats declines as well, as these prefer to settle on the shells of other oysters that have formed reefs. Knowing this, oyster restoration projects have been focused around testing methods that will increase recruitment of spat and allow oyster reefs to form. A current and ongoing restoration project in the Choptank River of the Chesapeake Bay, VA continually monitors the success of restored and natural oyster reefs in that area. This study focuses on eight restoration sites in the Choptank River and five environmental parameters (salinity, temperature, dissolved oxygen, distance from shoreline, and acreage) that may or may not contribute to their success. All eight restoration sites were deemed successful the last time that they were evaluated in 2016. The environmental conditions in these sites were very similar to each other and seem to be within the optimal range for the species, and thus, with the exception of temperature and salinity which significantly helped explain differences in live biomass between restorations sites, all other parameters did not contribute significantly to explain the differential success between sites. More interestingly, controlled factors in this study, such as restoration treatment, substrate type added, and number of spats planted per acre had a significant effect on the metrics that are used to determine oyster success. Specifically, restoration projects using stone substrate and seed led to higher average live biomass, density and shell volume than using seed only. We also concluded that sites with salinity of 8.2 and lower temperature tend to generate higher live oyster biomass. These environmental factors and methodological procedures should be taken into account when selecting sites and implementing oyster restoration sites.

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