Speaker: David Madison, Department of Fisheries and Wildlife, COMES, OSU

Topic: Bacteriophages significantly reduce mortality of larval Pacific oysters Crassostrea gigas from infection by the pathogenic bacterium Vibrio coralliilyticusRE98

Vibrio coralliilyticus (Vcor) is a bacterial pathogen that is well adapted to shellfish hatcheries and is very pathogenic to the larvae of the Pacific oysterCrassostrea gigas. Vcor has been associated with several large scale larval mortality events in Pacific Northwest hatcheries that interrupt the supply of seed oysters available to farmers. This thesis assesses the ability of bacteriophages (phages) to reduce larval oyster mortality by killing Vcor. Phages are viruses that selectively infect bacteria and are believed to be one of the main regulators of bacterial populations in nature. There are two main ways that Vcor can reach a lethal concentration in shellfish hatcheries. The scenario that is likely the most common is for a low concentration