The Great Lakes Fishery Commission has awarded a SUNY Oswego conservation geneticist a $62,822 grant to study small, bottom-dwelling Lake Ontario fish called deepwater sculpin—once thought extinct there.
Deepwater sculpin, a species with a flattened head, side-mounted eyes and distinctive fanlike dorsal fins, once thrived in Lake Ontario, but disappeared from scientists’ sampling sites from the 1960s through 1996.
Welsh will conduct DNA analysis to determine whether today’s deepwater sculpin are back from supposed extinction or drifted here from the upper Great Lakes, and whether these finger-length fish could become plentiful enough to make part of a healthy, native diet for a depleted population of lake trout currently feeding on non-native alewives.
“The main impetus for this is Maureen Walsh at the U.S. Geological Survey,” said Welsh, who began at SUNY Oswego in 2006 and has worked on studies of lake sturgeon and invasive shrimp. “She’s been doing field work on deepwater sculpins for the last few years.”
Missing for three decades
Walsh, a research fishery biologist with the USGS Great Lakes Science Center’s Lake Ontario Biological Station in Oswego, said her agency, the state Department of Environmental Conservation and Canadian partners sample the lake annually for many species of animal life. Deepwater sculpin had been plentiful from at least the 1920s through the 1950s, then disappeared.
The first specimen in modern times appeared in Canadian waters in 1996. Then, in 1998, a USGS crew found one at an agency sample site, and more and more each year. Last year, Walsh said, U.S. and Canadian biologists captured 103 deepwater sculpins in their surveys. This year, U.S. crews alone have collected 92.
“Obviously, there’s a continuing trend, and we’re seeing a range of individuals and sizes,” said Walsh. That is important, she said, because it indicates they are both reproducing and living long enough to become full length, 5 to 7 inches.
SUNY Oswego’s Welsh, tasked with the DNA analysis to determine the heritage of the modern deepwater sculpin population, had a quandary: where to find comparison specimens. Cornell University’s Museum of Vertebrates came through with fin clips from deepwater sculpins captured in the 1940s.
Another challenge involved the old specimens being preserved in formalin, which can bind with DNA, making it unusable for study. Through test procedures, Welsh found a way to isolate DNA from the 60-plus-year-old specimens.
Native species, healthier ecosystem
Determining the ancestry of today’s small but growing crop of deepwater sculpin, foraging at mean depths of nearly 420 feet, is important to the lake trout population. The DEC has stocked lake trout to restore their numbers, but the deepwater sport fish feeds primarily on alewife, a non-native species of herring. Walsh said alewives contain an enzyme that can have a negative effect on lake trout reproduction.
Welsh and Walsh said the goals of the genetic study are to determine how today’s deepwater sculpin are related to the historic Lake Ontario population, and if the population could rebound substantially enough, over time, to provide an alternative source of lake trout prey.
“So far, we have not identified any deepwater sculpin from lake trout diets,” Walsh said, but she pointed out that digestion often makes such identifications difficult.
Whether the return of deepwater sculpin benefits lake trout or not, Welsh finds it an exciting development for Lake Ontario.
“The goal in the Great Lakes is to restore more of a native ecosystem,” she said. “There is impetus to revive native species.”
PHOTO CAPTION: DNA testing—Amy Welsh, assistant professor of biology at SUNY Oswego, displays some of the genetic analysis equipment she will use in the DNA study of Lake Ontario’s deepwater sculpin, two specimens of which are in jars in the center foreground. The multichannel pipette she holds can load eight samples at a time into a tray. The machine in the background, a Beckman Coulter CEQ 8000 genetic analysis system, can process 96 samples at a time, displaying results on a linked computer screen.
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(Posted: May 12, 2010)