OSWEGO — Research by Amy Welsh of SUNY Oswego’s biological sciences department is contributing to an effort to remove lake sturgeon from the state’s threatened species list.
Under a $42,102 grant from the New York State Department of Environmental Conservation, Welsh is studying whether offspring of Oneida Lake sturgeon can be used to stock rivers and lakes in other parts of the state.
To bring lake sturgeon back from threatened status, New York needs to have eight separate self-sustaining populations, Welsh said. But the state’s propagation program to achieve that goal has been put on hold because of disease among lake sturgeon in fish hatcheries.
Finding a self-sustaining breeding population in Oneida Lake could help get the propagation program going again, she explained.
“The ultimate goal is a self-sustaining population where they will adequately reproduce themselves instead of needing a continuous stocking program,” Welsh said.
The St. Lawrence River’s propagation program was stopped by the threat of the fish disease VHS.
“They’re really having trouble with disease among lake sturgeon in fish hatcheries, so it would be great if we can find that fish in Oneida Lake can work as a source of stocking,” Welsh explained.
Diversity needed
The sturgeon in the Oswego River basin appear to be a likely breeding candidate as they have continued to thrive with good diversity because they were stocked by genetically distinct populations from Massena and Montreal.
Welsh will do the first genetic assessment of this population, which will confirm its level of diversity and overall viability.
Genetic diversity is key to a species’ viability. When a fish population lacks diversity and is more inbred, the fish are more likely to be less fit and hardy and to have more reproductive challenges. “It’s not a good idea to mate with your relatives,” Welsh noted.
“The higher the genetic diversity, the greater the evolutionary potential of the population,” she said. “Evolution needs genetic variables to work with. If there’s no genetic variety in the population, it will be less resistant to disease and evolutionary changes.”
Welsh will examine DNA from fin clips that Randy Jackson of the Cornell Biological Field Station collected from Oneida Lake sturgeon between 1995 and 2004. Her existing work studying the genetic diversity of the fish in Lakes Superior, Huron and Michigan provides samples she can compare with the local sturgeon in terms of diversity and viability.
Mating late
Female lake sturgeon may not mate until they are 30 years old, Welsh said, which complicates species survival as well as scientists’ research. Scientists have to wait much longer to find offspring to study.
And a species that needs to live that long to breed takes longer to recover when depleted, Welsh added.
Lake sturgeon was depleted primarily by over fishing, she said, while additional damming isolated the fish from access to new spawning grounds.
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