POPULATION DYNAMICS OF THE EASTERN OYSTER Crassostrea virginica IN DELAWARE INLAND BAY’S ESTURARY ECOSYSTEMS PRIOR TO SHELLFISH AQUACULTURE

Delaware is currently the only state on the Northeast Atlantic seaboard without commercial shellfish aquaculture. Legislation passed in 2013 and a lottery leasing process is currently underway with hope of having gear in the spring of 2018. Neighboring states have shown the economic and cultural benefits of functioning industry.  Three inland bays in Southern Delaware, due to protection from open waters, ease of access for workers, and a local tourism industry offer promising future locations for bottom leases. Oysters are functionally extinct within the Bays and with the rapid development of the local watershed, the ecological services oysters contribute are more important than ever. Oyster aquaculture may help restore depleted wild populations of oysters while filtering the water, providing structural habitat, and creating a new sources of jobs. There is a unique opportunity to study directly how aquaculture effects restoration, but baseline statics are essential.  This research aims to further understand the current oyster population by 1) developing baseline population densities using standardized survey methods for further use by management to measure changes over time and 2) investigating population dynamics by analyzing genetics of spatfall within the Delaware Inland Bays.

Oyster survey locations were by prioritizing habitat for hard substrate where oysters are more likely to settle and occur naturally, in this system hardened shorelines.  Standardized swaths were run along a permanent transect line in order to determine a population density at each location.  Results allowed for the production of the first mapping of wild oysters within the Delaware Inland Bays.

Genetic analysis will be done on spat, collected on tiles, to determine the diversity and potential source populations to the inland bays. Microsatellites (MS) offer a good way to measure differences between populations because they are highly polymorphic. Seven primers were chosen from previous research due to the ability of primers to multiplex. The goal of this is to compare allele frequencies among populations.  We will be able to identify if hatchery raised disease resistant oysters, from oyster gardening programs have been recruiting locally and hopefully identify potentially source populations for wild oysters.