Asian Carp: Freshwater Species of the Week

Few fish can inspire as much horror as the Asian carp (well, except perhaps the dreaded candiru).

But except for a few well publicized collisions with leaping fish, the Asian carp is rarely dangerous to human beings. Instead, ecologists warn that the Asian carp can wreak havoc on aquatic food chains by vacuuming up plankton and damaging submerged vegetation.

Asian carp are officially listed as invasive species in the U.S., and they are widespread throughout the Mississippi River Basin. Only a few individuals have been found in the Great Lakes so far, and fisheries managers are drawing a line in the sand to keep it that way.

This week, the Obama administration unveiled the 2012 Asian Carp Control Strategy Framework, with an attached budget of $51.5 million, reports the Associated Press. Agents will be stepping up monitoring and efforts to catch the fish in rivers that connect to the Great Lakes.

Officials will also be testing out scent-based lures for the Asian carp, an acoustic water gun that is hoped to repel them, and improved electric barriers and surveillance at locks.

Including this current commitment, the U.S. government has spent $156.5 million on keeping bighead and silver Asian carp out of the Great Lakes, reports the AP. The fish are known to be living about 55 miles away from the lakes in the Illinois River. Environmentalists have called for sealing off connections between the water systems, but others have warned such measures could cause flooding and restrict shipping traffic.

Meanwhile, the Army Corps of Engineers is working on a broader study that aims to propose long-term solutions. Results are expected in 2015.

The term Asian carp can be confusing, because it is generally applied to a group of related species, including the bighead (Hypophthalmichthys nobilis), silver (Hypophthalmichthys molitrix), grass (Ctenopharyngodon idella), and black carp (Mylopharyngodon piceus). These fish can get quite large, up to 110 pounds, and they eat copious amounts of plankton. They are related to goldfish, koi, and the common carp (Cyprinus carpio). The latter has already been established as an invasive species across most of North America for more than a century.

Asian carp are more recent invaders, having worked their way through the Mississippi over the past few decades. They are thought to have escaped from aquaculture operations in the South in the 1970s, where they were imported to clean ponds.

Asian carp are generally considered better eating than common carp, and they are prized as food in Asia, where they have been farmed for more than 1,000 years. As part of efforts to control their spread in the U.S., a growing number of anglers and biologists are trying to convince people to harvest them.

Can the beefy fish be contained? Only time will tell. Invasive species represent one of several serious threats to freshwater ecosystems, in addition to dams, diversions, pollution, and other problems. Systems that are already stressed are less likely to fight off invaders than healthy communities. The Great Lakes have been under siege for a long time.

Find out exactly where Asian carp have been spotted on the United States Geological Survey’s Nonindigenous Aquatic Species website.

 

Brian Clark Howard is a writer and editor with NationalGeographic.com. He was formerly an editor at The Daily Green and E/The Environmental Magazine and has contributed to many publications, including TheAtlantic.com, FastCompany.com, MailOnline.com, PopularMechanics.com, Yahoo!, MSN and elsewhere. His latest book, with Kevin Shea, is Build Your Own Small Wind Power System.

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