Published on November 20th, 2009 | by Dave Dempsey
Invasion of the Fish Snatchers?
Bighead carp are one of two non-native species of Asian carp causing widespread concern among Great Lakes advocates. The other is silver carp.
Great Lakes advocates are calling it a “conservation emergency” now that non-native Asian carp have been detected within seven miles of Lake Michigan. They want an immediate closure of locks and gateways leading to the lake in a literally”last-ditch” attempt to keep the fish out.
The fear is that the giant fish will disrupt the valuable Great Lakes sport fishery by outcompeting species at the top of the Lake Michigan food web, consuming the forage fish the established species depend on — and like many of the other 180 non-native aquatic species already in the Great Lakes, causing general ecosystem disruption.
The disclosure that the carp are within a short swimming distance of Lake Michigan is inspiring recriminations among advocates and federal agencies. The U.S. Army Corps of Engineers is the prime target. Charged with operating and maintaining an electric barrier in the Illinois River system, the Corps has appeared to shift responsibility for maintenance problems with the barrier.
The carp have been a YouTube sensation because of video showing them leaping into the water at the sound of a passing motor. The conservation coalition calls the fish ‘voracious filter feeders that can grow to more than 4 feet long, weigh up to 100 pounds and quickly dominate a body of water by gobbling up the same food that sustains native fish populations.”
Cam Davis, Great Lakes coordinator for the Obama Administration, cautions that the DNA evidence suggesting the carp are close to Michigan “is the best we have, and we believe it’s very accurate. But what we have not done is to find an actual carp body in these areas where sampling is telling us their genetic material may be. We still have not seen an actual carp show up.”
There is some disagreement about who introduced the fish to the Mississippi River system. EPA says catfish farmers imported them to control nuisance plant growth in aquaculture ponds. Others say state fish and wildlife agencies initiated the introduction. But there is agreement that the fish escaped the aquaculture facilities during floods in the 1990s and have been moving north ever since.
Photo credit: U.S. Fish and Wildlife Service.