SANDUSKY, Ohio — On July 30-31, Ohio Department of Natural Resources, Michigan Department of Natural Resources, U.S. Fish and Wildlife Service and U.S. Army Corps of Engineers collected 150 water samples from the Sandusky Bay and Sandusky River.
Analysis of these water samples indicated 20 samples out of 150 taken from throughout Sandusky Bay and Sandusky River have tested positive for the presence of silver carp environmental DNA. The eDNA samples were collected as part of extensive sampling effort conducted earlier this summer for Asian carp in Sandusky Bay and Maumee Bay in western Lake Erie.
No Asian carp were found through intensive electrofishing and test netting. Maumee Bay eDNA results are currently being analyzed.
Response
In response to the positive findings, both state and federal officials have already started collaborative discussions to implement additional investigative work in early September, including additional eDNA testing. All parties continue to work together to assess the current status of bighead and silver carp within western Lake Erie bays and select tributaries.
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.
Results
At present, eDNA evidence cannot verify whether live Asian carp are present, whether the DNA may have come from a dead fish or whether water containing Asian carp DNA may have been transported 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, funded through the Great Lakes Restoration Initiative to reduce the uncertainty surrounding Asian carp environmental DNA results.
Low numbers
Since extensive sampling conducted for this species this summer, as well as extensive sampling conducted historically, have yielded no live fish, the data suggests that if Asian carp are present, then they are in very low abundance.
“These eDNA samples provide useful information to help guide our monitoring of Lake Erie and our response to any threat of Asian carp to the Great Lakes,” said Charlie Wooley, U.S. Fish and Wildlife Service Midwest deputy regional director
“While there is still uncertainty about the source of eDNA, the recent findings provide another point of data as we work with Ohio and Michigan to assess the status of Asian carp in the area. I want to stress that recent fish sampling activities, such as gill netting and electrofishing, have not provided any physical evidence that live Asian carp are present in western Lake Erie.”
