Eukaryotic microbial diversity at shellfish aquaculture sites along the coast of Maine, USA

The main goal of this project was to establish a baseline moleuclar survey of waterborne parasites at commercial oyster aquaculture leases located within the well-defined coastal bioregions of Maine, USA (Southcoast, Midcoast, and Downeast). Genes from the parasites Dermo (Perkinsus marinus and Perkinsus chesapeaki), MSX (Haplosporidium nelsoni), Cryptosporidium parvum, and Toxoplasma gondii were quantified in oyster tissue DNA samples from each of six study sites by quantitative PCR. Surface water DNA samples were collected in the vicinity of aquaculture operations on each of the oyster sampling dates to determine the extent to which shellfish parasites contributed to the overall plankton assemblage via metabarcode sequencing of the 18S rRNA gene. A further goal of this project was to determine the effect of the oyster parasites Dermo and MSX on oyster health and the degree to which their presence makes oysters susceptible to additional parasitic infections (C. parvum and T. gondii) that could pose a threat to consumers of raw or undercooked oysters. This research will contribute to the ongoing development of a sustainable and safe shellfish industry in coastal Maine by defining the potential for high versus low risk areas for harvesting wild shellfish and/or setting up shellfish aquaculture facilities.