The discovery of stocked lake sturgeon bearing eggs in the Oswegatchie River and Oneida Lake's outlet this spring marks a milestone in restoration efforts that began nearly 20 years ago, biologists said Monday.
Dawn Dittman, a researcher with the U.S. Geological Survey's Tunison Laboratory in Cortland, caught two egg-bearing females in gill nets in Oneida Lake's outlet during sampling in April. She caught two more in May in the Oswegatchie River in northern New York.
The fish were grown in a hatchery from eggs and sperm taken from wild lake sturgeon in the St. Lawrence River and were released in 1995 by the state Department of Environmental Conservation. They're the first mature female stocked sturgeon since restoration began. Mature males have been found in previous years, but they typically mature earlier.
Lake sturgeon is a threatened species throughout the Great Lakes region, and restoration programs are also under way in Wisconsin and Michigan. The fish take 15 to 25 years to reach reproductive age. The females found in New York were about 5 feet long and weighed about 50 pounds, but the species can grow to more than 7 feet long and 200 pounds.
DEC biologist Lisa Holst said the fish were released after examination, and it's hoped that they'll spawn.
Lake sturgeon have continued to reproduce in the wild in the lower Niagara River, the lower St. Lawrence River and the Black River near Watertown. In 2009, lake sturgeon began using spawning beds created by the New York Power Authority upstream of its Moses-Saunders Power Dam near Massena.
Dittman said biologists will assess potential spawning areas in waterways where sturgeon have been stocked, and possibly make improvements if conditions aren't favorable for the fish. Sturgeon like to spawn in swift water below a barrier like a waterfall or dam, depositing eggs among rocks and gravel where the hatchlings will find protection. Any young produced this spring should be large enough to be captured in nets in about two years, Dittman said.
DEC released 18,000 lake sturgeon in 1995 into Oneida, Cayuga and Black lakes and the Oswegatchie River. Stocked fish have also been released in subsequent years into the St. Regis, Genesee and Raquette rivers, Holst said.
The lake sturgeon, New York's largest freshwater fish, is one of three sturgeon species found in New York. The Atlantic and shortnose are found in the Hudson River below Troy. All species are protected because their numbers were sharply diminished by overfishing, pollution and dam construction.
Scientists estimate that sturgeon populations in the Great Lakes region are at about 1 percent of what they were before 1850.