Are Yellow Perch Native to the Adirondacks After All?
by Mary Thill
One of the truths we hold self-evident in the Adirondacks is that yellow perch are not native. They are also not welcome, mainly because they pose a threat to brook trout, our emblematic fish.
This has been the foundation of upland Adirondack fisheries science since at least 1889, when Fred Mather surveyed the region’s fish and reported to the New York State legislature, “[I]n no waters of the Adirondacks, except on its borders, did I either find or hear of one of the most common of New York fishes, the yellow perch, Perca fluviatilis [now Perca flavescens].”
As recently as last month, a group of fish scientists sharing research at a conference in Old Forge ruled out using yellow perch as a sentinel for mercury contamination on the grounds that it is not endemic to the Adirondacks.
But a new study by a molecular biologist at Paul Smith’s College challenges that assumption. Lee Ann Sporn, working with students and colleagues, set out to determine when yellow perch first arrived in Lower St. Regis Lake, on whose shores the college sits. They found that perch may predate people by as much as 1,000 years.
“We’d like to suggest that yellow perch may in fact be native to upland lakes in the Adirondack Park,” Sporn told a meeting of the New England Association of Environmental Biologists in Lake Placid on March 21.
Sporn, who was a biomedical researcher before she was a biology professor, looked at environmental DNA, or eDNA, in a sediment core extracted from the bottom of Lower St. Regis Lake. The lake contains yellow perch—assumed to be a 19th century invader—so she expected to find traces of perch genetic material near the top of the earthen sample. But she also found mitochondrial perch DNA, which she describes as a “mini bar code,” in deeper sediments accumulated long ago.
Yellow perch are widespread in the Adirondacks. But because they cannot swim up rapids or waterfalls, the belief has been that they got to these highlands by stocking, mostly between 1919 and 1932, or they were accidentally introduced when fry were used as bait minnows. “With the expansion of these populations brook trout and other endemic forms declined greatly, probably due to the perches’ omnivorous habits,” states a 1981 New York State Department of Environmental Conservation (DEC) report on Adirondack fishes.
Yellow perch are obliging to a variety of baits and lures, the first fish caught by many a kid. Some people (myself included) love to eat them, but brook trout fishermen revile them—some even toss them on shore to die.
DEC is skeptical about the new DNA findings. Spokesman David Winchell said by e-mail, “At this time DEC does not have sufficient evidence that yellow perch are native to the Adirondacks based on this one study which at this time has not received peer review. Currently there is too much evidence to the contrary, including extensive early fish surveys in the Adirondacks which did not find yellow perch.”
The discovery could have repercussions for fish management. DEC “reclaims” ponds to restore brook trout, killing off yellow perch and other fish before reintroducing Adirondack strains of trout. It has reclaimed Black Pond, which is connected to Lower St. Regis Lake. “Native brook trout populations do not exist for long in waters where yellow perch have been introduced. DEC will continue to work to restore native Adirondack heritage brook trout populations which clearly have declined significantly since the early 1800s,” Winchell wrote.
Sporn is not maintaining that every Adirondack lake has perch. “I’m sure there are perchless lakes,” she says, and as a control measure she tested a sediment core from Wolf Lake, near Newcomb, where there currently are no perch. No perch DNA was detected.
Scientists have been using DNA bar-coding in the biomedical realm for decades, as anyone who watches CSI can attest. eDNA is now finding wider application in environmental sciences, most famously to detect the presence of invasive Asian carp in Chicago canals that connect the Mississippi watershed to the Great Lakes.
The Adirondack perch study may be one of the first cases of eDNA being used to determine the native range of a species.
DEC would not permit an interview with a staff fisheries biologist. But other scientists at the New England Association of Environmental Biologists seemed to find Sporn’s method of applying of eDNA-sensing to sediment cores sound, though they would like to see it tested on a species known to have been recently introduced, such as zebra mussels in Lake Champlain. Sporn says she plans to do such a study in the near future. She is also writing up her findings for submission to a peer-reviewed journal and will present them at the Adirondack Research Consortium conference in Lake Placid in May.
Since eDNA is highly sensitive to detection, Sporn’s peers are concerned mainly about the possibility of contamination—that present-day perch DNA may have worked its way down the core. Sporn says there was little risk of mixing—“the sediment is more like fudge than pudding”—and she excised samples from the center of the core with surgical precision. She said she would not have made her findings public if she were not confident in their credibility.
Sporn says the project originated with students who wished to develop skills in molecular biology. They teamed up with her colleague Curt Stager’s paleoecology class to try to figure out when yellow perch first appeared in Lower St. Regis Lake. Stager says that the findings have not lessened his support of DEC’s policy of reclamation to help Adirondack brook trout. “I just want to be open about what the trade-offs/facts/consequences are,” he wrote in an e-mail.
Despite Fred Mather’s 1889 report, the historical record is not all that clear. The naturalist John Burroughs, traveling through the Adirondacks in 1863, wrote that Lake Sanford, near Newcomb, “abounds in white and yellow perch and in pickerel.” People were moving fish from lake to lake as early as the 1840s, Mather wrote, including pike from Lake Champlain to Lake Sanford. As he cautioned the state’s commissioners of fisheries, “It is possible that the waters may contain other species not observed by me during the limited time in which the collection was made.”