FREMONT: Sandusky Bay, a watery playground for boaters and anglers, is becoming a battlefield and testing ground in the fight to protect Lake Erie.
On one side: federal and state biologists and agencies including the Ohio and Michigan departments of natural resources, the U.S. Fish and Wildlife Service, the U.S. Geological Survey and the U.S. Army Corps of Engineers.
On the other: Asian carp, the dreaded invasive species that pose a “very real” threat to the Lake Erie, according to Rich Carter of the Ohio Department of Natural Resources.
At stake: a Lake Erie ecosystem that generates more than $800 million in sport and commercial fishing.
Wildlife experts fear Asian carp varieties will mushroom in number in Lake Erie and will out-compete native fish for available food. Asian carp, a voracious and prolific species, are a threat to walleye, perch, bass and other Lake Erie fish that feed on plankton.
They don’t just invade, they destroy the food chain from the bottom. They conquer and dominate.
The big issue has been whether the Asian carp might circumvent electrical barriers on a canal 35 miles southwest of Chicago and get into Lake Michigan and spread throughout the Great Lakes.
The fish are also ascending the Ohio River, with some as far east as the Greenup Dam near Portsmouth, Ohio.
Right now, the major weapons in detecting Asian carp in Lake Erie are environmental DNA (eDNA) tests and the work of forensic fish experts.
The eDNA tests detect Asian carp genetic material from such sources as fish scales, fish mucous, fish wastes and even excrement in the water from fish-eating birds, Carter said.
Federal and state agencies are working to assess emerging evidence that bighead and silver carp have reached western Lake Erie. That effort intensified this summer when Asian carp genetic material was confirmed for the first time in Sandusky and Maumee bays, although no live fish were found.
The prevailing thought is that Asian carp are in Sandusky and Maumee bays in small numbers and have not reached young-producing populations.
“Right now, it’s a numbers game,” Carter said of the invasion. “And we think the numbers are small.”
The next step is to determine the source of the genetic material found in the two bays.
On Tuesday, federal and state fishery staffers in three boats worked the 150-yard-wide Sandusky River north of Fremont with gill nets and electric shock equipment in the latest round of testing. The results: no mature Asian carp.
The crews worked Sandusky Bay on Monday with similar results. State personnel also visited bait shops across northern Ohio.
“We will continue to address the uncertainties about the status of Asian carp in Lake Erie with our partner agencies,” Carter said Tuesday. That includes “ramping up our search efforts for live fish or other sources of eDNA.”
The latest Maumee Bay eDNA test results are expected to be released by next week.
Ontario is expected to begin eDNA testing this fall.
At present, eDNA evidence cannot verify whether live Asian carp are present, whether the DNA might have come from a dead fish or whether water containing Asian carp DNA might have been transported from other sources, such as bilge water or bait buckets.
First evidence
In July, federal and state agencies announced that Asian carp eDNA was found in six samples from Sandusky and Maumee bays in testing of Ohio and Michigan waters. That was the first evidence of the Asian carp in Lake Erie. Four samples from Sandusky Bay tested positive for bighead carp and two samples from Michigan in Maumee Bay tested positive for silver carp.
On Aug. 28, genetic material was found for silver carp in 20 of 150 samples at Sandusky Bay.
That triggered a week on extensive electroshocking and gill netting in the Sandusky and Maumee bays and their main tributaries. No bighead or silver carp were found.
“The sampling results are very encouraging, especially since we intensely focused on areas where we believed we had the greatest chance of finding these fish,” said Carter, ODNR’s executive administrator of fish management and research.
His agency tracked down three historic cases of Asian carp being caught in Lake Erie.
Commercial fishermen netted three bighead carp in Lake Erie: two in Sandusky Bay and one near Pelee Island, Carter said.
One adult fish was caught in 1995 and two in 2000. Testing indicates the three fish probably were raised on southern U.S. fish farms, he said. How they got into Lake Erie is unknown.
A report the agency Fisheries and Oceans Canada released this summer says Asian carp probably will enter the Great Lakes near Chicago.
Other points from that report:
• Asian carp are likely to survive and spread in all five Great Lakes within 20 years.
• It could take as few as 10 mature females and 10 or fewer mature males in one Great Lake to reproduce.
“The Asian carp are moving toward the Great Lakes far faster than government response, and this report shows that the cost of inaction will be devastating,” said Andy Buchsbaum, director of the National Wildlife Foundation’s Great Lakes office.”
In July, President Barack Obama signed legislation that requires the Corps of Engineers to expedite the preparation of a plan to block Asian carp from getting into the Great Lakes.
The Stop Invasive Species Act requires the Corps to submit to Congress an expedited action plan with options for keeping the fish out of the Great Lakes via 18 specific pathways. That includes four possible Ohio River-Lake Erie links in Ohio. That plan must be completed in 18 months.
Bob Downing can be reached at 330-996-3745 or bdowning@thebeaconjournal.com.