Can an underwater species have a family tree? And, if so, what can we learn about threatened fish species when we trace their genetic origins?
A West Virginia University professor was recently awarded a grant from the U.S. Geological Survey to conduct genetics research on a species of fish in the Great Lakes region.
Amy Welsh, assistant professor of wildlife and fisheries resources in the Davis College of Agriculture, Natural Resources and Design, will use the genetic data to create “family trees” for lake sturgeon (Acipenser fulvescens) in the St. Clair-Detroit River System
Doing so will help researchers identify from where the native fish come and how many are actively spawning – two key pieces of information needed to understand how to best help the endangered species begin to thrive once again.
The $65,000 grant will fund the two-year project, including a research position for a graduate student.
Large, elusive fish at the top of the food chain, lake sturgeon are bottom feeders adept at controlling invasive species in the rivers and lakes they inhabit. A long-lived species, lake sturgeon reach sexual maturity later in life and are known for intermittent spawning.
“Lake sturgeon have been around since the age of the dinosaurs,” Welsh said. “Unfortunately, overfishing and habitat alterations, including the construction and operation of dams, have attributed to a decline in population.”
In fact, most current populations are estimated to be 1 percent of historic population sizes. The species is listed as threatened or endangered in 19 states, including Michigan, and at the federal level in Canada.
“Fishing of lake sturgeon is heavily restricted in both the United States and Canada,” Welsh said. “Management efforts are beginning to focus on improving habitat in an effort to encourage natural recolonization or increased spawning at impacted sites.”
In the Detroit River area, specifically, officials constructed a natural spawning reef upstream. Since its creation in 2008, researchers have collected viable eggs and larvae suggesting the species is successfully spawning on the reef.
“The success of the spawning reef indicates that natural colonization of a new habitat has occurred. It’s like the old adage, ‘If you build it, they will come,’” Welsh said. “However, questions remain about the origin and number of founding individuals.”
That’s where she steps into the picture.
Determining where the fish originate and the number of spawning individuals is difficult to address through traditional field work, so Welsh will extract DNA from larval samples and use microsatellites, repeating sequences of base pairs of DNA.
“Microsatellites are highly variable genetic markers that are useful for detecting genetic differences at a fine scale both geographic and temporal,” Welsh explained.
With these methods, she’ll be able to identify genetic differences, assign individual fish to their origins, and better understand the relationship of SCDRS spawning population to others found throughout the Great Lakes.
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