Christopher Kan ’13 (Biology and Anthropology). Bowdoin College. “A Statewide Survey of Genetic Diversity in Alosa aestivalis.” John Lichter and Vladimir Douhovnikoff, advisors.
Blueback herring are anadromous fish that live as adults in the ocean and migrate to spawn, in rivers from Florida to Maine. They are critical ecological link between marine fisheries and inland watersheds. Through their mortality they provide nutrient input. They also are critical prey for economic species of interest such as cod and atlantic salmon. Bluebacks themselves were exploited to make smoked fish and shipped from New England around the world for over a hundred years. Bluebacks have been threatened for several decades due to habitat destruction due to dams and overfishing. Recent efforts across Maine to remove dams, restore stream habitat and reduce fishing pressure have begun to pay off.
Monitoring this recovery and gathering data to ensure that future policies support the recovery are critical. My project seeks to use microsatellite markers to assess the genetic diversity across the state. This data will be used in several ways. Most directly genetic diversity can be a measure of a population’s ecological health.
Genetic diversity can also hint toward past ecological events. Populations that exhibit lower diversity have likely encountered population bottlenecks in the past. The degree to which this effect is observed indicated the level of decline a population has experienced. This is particularly valuable in Maine where dams have existed since the 1800s, before reliable historical records. Genetic data can further be used to determine migration patterns. Microsatellite data will be analyzed to determine the genetic distance between populations. This data coupled with analysis overlaying physical distance can give a measure of the number of fish that cross watershed boundaries. These boundaries are important for stock management. Managers need to know if any project along a watershed will affect a subpopulation greatly by eliminating their habitat or simply displace them to other parts of their range.
My project will continue well into the year. The field season will end in September. During the year I will begin genetic analysis and data complilation.