Paul Rawson

The research in the Rawson lab investigates the ecological genetics of marine benthic invertebrates. A major focus of our work continues to center on the evolutionary dynamics of hybridization between blue mussels in the genus Mytilus using a combination of phylogenetic, physiological and molecular biological approaches. Past project have documented the distribution of two species of blue mussel Mytilus edulis and M. trossulus and their hybrids in the Gulf of Maine and the degree to which species-specific larval thermal tolerance, dispersal and settlement contribute to geographic variation in abundance of these two species.

More recent and continuing work has employed phylogenetic analyses to estimate the historical patterns of extinction and colonization for M. trossulus in the northwest Atlantic, DNA sequence-based analysis of the role of natural selection in structuring blue mussel populations on east coast of North America and in the Baltic and North Seas, and molecular studies of the evolution of gamete recognition and the evolution of reproductive barriers among blue mussel species.

In addition to blue mussels, we have on-going projects working with sea scallops, Placopecten magellanicus, and the eastern oyster, Crassostrea virginica. We are using a combination of ecological, population genetic and geochemical fingerprinting approaches to ask whether in-shore sea scallop populations in Cobscook Bay and Penobscot Bay, Maine are demographically isolated from off-shore populations, such as the large scallop beds on Georges Bank.

We have partnered with the Maine Oyster Growers working group, the Maine Aquaculture Innovation Center and the Maine Aquaculture Association to continue selective breeding efforts for the eastern oyster. Oyster culture in Maine is typically limited by sub-optimal growth conditions and disease pressure from Juvenile Oyster Disease. Through the University of Maine Cooperative Oyster Broodstock Program we are using selective breeding and cross-breeding between improved oyster stocks to develop oyster lines that enhance production at Maine’s oyster farms.