Friday, July 13, 2012

UPDATED: Asian carp DNA found in Sandusky Bay, Lake Erie

Efforts to develop strategies to keep the invasive Asian carp from ever entering Lake Erie may already be moot.

Federal and state wildlife officials working in conjunction with academic researchers on Friday announced six water samples taken from both the Sandusky and north Maumee bays tested positive for the presence of Asian carp environmental DNA in both Michigan and Ohio waters of Lake Erie.

These positive samples were among 417 taken from Lake Erie in August 2011, and more than 2,000 samples taken from the Great Lakes Basin since 2010.

The Lake Erie batch was recently analyzed and test results were confirmed by eDNA researchers this week. The six positive samples represent less than 1.5 percent of the Lake Erie samples.

However, four samples from Sandusky Bay tested positive for bighead carp eDNA, while two samples from north Maumee Bay, in Michigan waters, were positive for silver carp eDNA.

Both species are considered to be among the most serious invasive species to ever threaten the Great Lakes’ fisheries, worth billions annually in commercial fishing and sport angling activities.

The results of a study released this past week by Fisheries and Oceans Canada says that as few as 10 breeding pairs of Asian carp could produce a viable colony in any of the Great Lakes, including Lake Erie, which is considered to have good spawning habitat for the various species which make up this group of fishes.

In response to these findings, electro-shocking and netting began Friday in Sandusky Bay with no evidence of Asian carp having been found.

But additional testing and monitoring are planned by the Ohio and Michigan departments of natural resources in conjunction with partner agencies, the two states say.

"We are concerned about the eDNA test results and we also recognize that this is screening level technology but what it does show us is the presence of that marker," said Rich Carter, fish management administrator for the Ohio Department of Natural Resource's Division of Wildlife. "What we have to do is balance this information with other data-collecting mechanisms."

While the eDNA findings indicate the presence of genetic material left behind by the species - such as scales, excrement or mucous – this does not ensure that Asian carp are now established in Lake Erie.

Carter did note that between 2000 and  2003 three Asian carp were recovered from Lake Erie, though how they arrived there is unknown.

Positive eDNA tests are regarded by the scientific community as one indicator of the species’ recent presence, though not necessarily from living specimens. That is because positive results can occur whether the organism was alive or dead, biologists for the two states say.

And though the eDNA findings do suggest the possible presence of Asian carp, officials have no physical evidence any fish have actually migrated into the Great Lakes from the Mississippi River drainage system that includes both the Ohio and Missouri River watersheds.

Carter said also that the U.S. Army Corps of Engineers is  in the process of evaluating any potential "pathways" between the huge Mississippi River drainage and the massive Great Lakes drainage in an effort to identify any possible connectors.

Such a study is expected by the end of July, Carter says.

In response to the positive test results, officials from the Michigan and Ohio DNRs, state environmental protection agencies along with their federal counterparts are developing a plan of action in collaboration with the joint eDNA research team, Carter says.

“The thing to keep in mind is that we have done - and will continue to do - sampling," Carter said. "It is important to look at all the information and work with our partners in collecting the information," Carter said. "This lake is Ohio’s greatest resource and our main objective is to keep it healthy,” said Rich Carter, the Executive Fish Management and Research Administrator for the Ohio Division of Wildlife.

This effort will seek to obtain follow-up samples and test results as quickly as possible. Test results from future water samples will dictate the nature of further response methods.

“The results from these water samples are certainly of concern, as this marks the first time Asian carp eDNA has been detected in water samples taken from Lake Erie, or any of the Michigan waters intensively surveyed for the presence of invasive carp,” also said Michigan DNR Fisheries Division Chief Jim Dexter

Carter did decline to say whether the arrival and any subsequent establishment of a viable Asian carp population is inevitable.

Anglers are urged to become familiar with the identification of Asian carp, including both adults and juveniles, as the spread of juvenile Asian carp through the use of live bait buckets has been identified as a potential point of entry into Great Lakes waters.

Identification guides, frequently asked questions, management plans and an online reporting form are available online at and, or call 800-WILDLIFE.

- Jeffrey L. Frischkorn
Twitter: @Fieldkorn

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