Intraspecific diversity and conservation biology of fishes

My research program uses a variety of methods to examine the intraspecific biodiversity of freshwater and marine fishes, especially those that occur in Atlantic Canada. We use DNA sequencing of mitochondrial DNA to learn about historical components of diversity - for example, to trace contemporary populations back to the glacial refugia they occupied during the ice ages. We study more rapidly evolving sequences, called microsatellites, to measure the extent to which species are split into populations now, how much mixing or dispersal goes on between populations, and to determine how much genetic variation exists within populations. We study particular genes in fishes to determine if they show local adaptations. We study body morphology to examine how populations differ in their ecological adaptations. We use common garden experiments to test whether local populations of fishes show differences in their adaptations, for example, in their ability to withstand common environmental stresses such as acidity (low pH), and also to test whether the amount of inbreeding within populations affects the ability of fish to tolerate stresses such as low pH. We study a variety of fish species, including but not limited to rainbow smelt, lake whitefish, wolffishes, and American shad.I study intraspecific biodiversity to gain valuable fundamental knowledge, but also because it is important for conservation reasons. As a northern country, much of which was covered by glaciers during the ice ages, Canada has relatively few species compared to warmer unglaciated parts of the world, but its species are divided into a myriad of populations, and these populations are often quite diverse. This diversity within species is a substantial part of the total biodiversity in Canada and elsewhere. It is important to recognize diversity within species, because understanding intraspecific biodiversity is an essential first step towards conserving it. It is important to conserve intraspecific biodiversity, because it contributes to the functioning of ecosystems, is part of our natural legacy, and provides the reservoir of variation that allows species to adapt to future environmental changes.