Asian carp environmental DNA (eDNA) has been detected in three of 350 water samples collected from western Lake Erie’s Maumee Bay and Maumee River between July 31 and August 4.
The three samples, all positive for silver carp eDNA, were found in Maumee Bay – two in Michigan waters and one in Ohio waters.
The water samples were collected by the Ohio Department of Natural Resources (ODNR), Michigan Department of Natural Resources (MDNR), U.S. Fish and Wildlife Service (Service) and U.S. Army Corps of Engineers as part of an extensive sampling effort developed in response to the discovery of Asian carp eDNA in water samples taken from Maumee and Sandusky Bays in summer 2011.
In addition to the three positive eDNA samples recently found in Maumee Bay, the ODNR, MDNR and Service previously announced that of 150 samples collected from Sandusky Bay in late July, 20 tested positive for silver carp eDNA.
The western Lake Erie response plan also included intensive electrofishing and test netting in the Maumee Bay and River and the Sandusky Bay and River in August 2012, during which time no Asian carp were found.
“I cannot overstate the importance of our Great Lakes fishery to the economy and quality of life in Michigan,” said MDNR Fisheries Chief Jim Dexter. “We will continue working with our partner agencies to identify the source of Asian carp eDNA in western Lake Erie so we can effectively protect the Great Lakes from the threat posed by silver and bighead carp if the species were to establish viable populations in the Great Lakes or their tributaries.”
Addressing the Asian carp threat is a priority issue for the Great Lakes Fishery Commission’s inter-jurisdictional Lake Erie Committee, which includes representation from Pennsylvania, New York, and the province of Ontario in addition to Michigan and Ohio. The Service and other federal agencies are also key players in Asian carp research and investigative work.
“We will keep working to address the uncertainties about the status and source of Asian carp in Lake Erie with our partner agencies through the Lake Erie Committee,” said Rich Carter, ODNR Executive Administrator of Fish Management and Research. “We are aggressively searching for live Asian carp in Lake Erie through different techniques and urge anglers to be vigilant in watching for these species while on the lake as well.”
Researchers say eDNA analysis provides a tool for the early detection of Asian carp at low densities, and these latest positive results heighten concern about the presence of Asian carp in western Lake Erie. However, the analysis cannot provide or confirm information about the number or size of possible fish.
“Our field crews were out on the water numerous times over the last couple of months, using multiple gear types and they found no live Asian carp,” said U.S. Fish and Wildlife Service Midwest Deputy Regional Director Charlie Wooley. “We are still trying to pull back the curtain on what the source is for these positive eDNA samples.”
At present, eDNA evidence cannot verify whether the DNA may have come from a live or dead fish, or from other sources such as bilge water, storm sewers or fish-eating birds. The Service, U.S. Army Corps of Engineers and the U.S. Geological Survey are leading a two-year Asian Carp Environmental DNA Calibration Study (ECALS), funded through the Great Lakes Restoration Initiative to reduce the uncertainty surrounding Asian carp eDNA results.
Extensive sampling conducted for Asian carp this summer and fall have yielded no live fish, suggesting that if Asian carp are present, then they are in very low abundance.
Asian carp, including bighead and silver carp, pose a significant threat to the Great Lakes ecosystem and economy. Help from the public, especially Great Lakes anglers, will be imperative moving forward. All anglers are strongly encouraged to learn how to identify 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 possible entry point into the Great Lakes. A video teaching people how to identify bighead and silver carp is available on the Service’s YouTube channel.
If anglers or constituents have observed or captured an Asian carp, immediately notify ODNR at 800-WILDLIFE (945-3543) or MDNR at 800-292-7800. Photograph the fish from nose to tail, and retain the fish on ice for verification. Online submission forms, identification guides, frequently asked questions and management plans are also available at www.michigan.gov/asiancarp and www.wildohio.com.
Logo courtesy Ohio Department of Natural Resources