ODNR, USGS Collaborate on Grass Carp Study
OutdoorHub 10.29.13
ODNR develops tactical plan to address threats from invasive carp
The Ohio Department of Natural Resources (ODNR) and the U.S. Geological Survey (USGS) collaborated on a USGS study released this week on the origins of grass carp caught in the Lake Erie basin. The study analyzed four grass carp provided by commercial fishermen to ODNR from Ohio’s Sandusky River and concluded through bone analysis that the fish were at least one year of age and likely produced through natural reproduction in the Lake Erie basin.
Grass carp eat aquatic vegetation, and there is concern that should the species spread, they could impact fish and waterfowl habitat through aquatic plant removal. The ODNR Division of Wildlife is actively engaged in discussions with the Asian Carp Regional Coordinating Committee, U.S. Fish and Wildlife Service (USFWS), USGS, Great Lakes states as well as Fisheries and Oceans Canada and the province of Ontario about next actions to address knowledge gaps about grass carp population status in the Great Lakes, evaluate risk from this species and potential to develop integrated pest management strategies to control impacts of feral, naturally reproducing grass carp.
“Grass carp are considered an Asian carp but should not be confused with bighead and silver Asian carp,” said ODNR Division of Wildlife Fish Administrator Rich Carter.
Bighead and silver carp are threatening to invade the Great Lakes from the Mississippi River Basin, and extensive effort is directed at closing the connections between these basins. Bighead and silver carp compete with native fishes for microscopic plankton and compromise the quality of sport fishes.
Grass carp have been stocked across the U.S. since the 1960s. Feral (wild) grass carp have been documented from numerous locations in the Great Lakes and Lake Erie since the mid-1980s, but ploidy status (sterile versus fertile) has not been tested until recently. Feral grass carp have been collected in the Ohio River watershed since 1980. Reproducing populations exist in the lower Ohio River. Recent research documented fertile (diploid) grass carp in Lake Michigan and Lake Erie at Monroe, Mich.
Ohio and 42 other states allow the sale of sterile (triploid) grass carp that are used for controlling aquatic vegetation in ponds. Ohio law does not allow importation or stocking of fertile (diploid) grass carp. Ohio law has allowed importation and stocking of certified sterile (triploid) grass carp since 1988. A certification program is administered by USFWS.
ODNR has developed an Ohio Asian Carp Tactical Plan that provides detailed approaches to address the threats by bighead, silver and grass carp. The plan is currently being finalized incorporating stakeholder comments. ODNR’s strategies to address grass carp outlined in the plan include:
- Statewide testing of fish collected in ODNR assessments to determine fertility.
- Random testing of certified triploid grass carp for fertility status in Ohio shipments.
- Enforcement of prohibitions on diploid grass carp importation.
- Engaging regional partners in discussions on grass carp use and threats/risk assessment.
