Frequently Asked QuestionsWhat are Asian carp?
Asian carp are a group of highly invasive fish species capable of causing economic, ecological and human health harm. They include the flowing species:
- bighead carp (Hypophthalmichthys nobilis)
- black carp (Mylopharyngodon piceus)
- grass carp (Ctenopharyngodon idella)
- silver carp (Hypophthalmichthys molitrix)
- large-scale silver carp (Hypophthalmichthys harmandi)
All five species listed above are large, invasive, filter-feeding fish that would be capable of consuming vast quantities of microscopic plants and animals daily if populations were established in Michigan waters. In particular, bighead and silver carp are a considered to pose a significant and immanent threat to the Great Lakes Basin since they are rapidly spreading in streams, rivers and lakes in the Mississippi River Basin and are currently just a few miles from Lake Michigan near Chicago, Illinois.
Bighead, silver, black and large-scale silver carp are not currently established in the Great Lakes Basin or any of Michigan's inland waters. However, grass carp can be found in isolated waters in Michigan and the Great Lakes region.
How did Asian carp get here?
Bighead and silver carp were imported into the southeastern United States in the 1970s to remove algae and suspended matter out of catfish farm ponds and wastewater treatment ponds. While the exact manner of their release into the wild is still debated, it is widely believed that during large flood events in the mid-1990s some ponds overflowed their banks and Asian carp were released into local waterways in the Mississippi River Basin.
Why are Asian carp a problem?
Because of their large size, voracious appetites and spawning processes, Asian carp can out-compete native species for both food and habitat. Bighead carp reach up to 100 pounds and juveniles can consume up to 140 percent of their body weight daily while adults can consume up to 40 percent of their body weight daily.
Silver carp, although smaller than bigheads, have a habit of jumping up to five feet out of the water when disturbed by vibrations commonly caused by boat motors, thus creating a safety hazard. Both species can spawn multiple times annually, quickly displacing native species.
The Asian carp species listed in this document are considered aquatic invasive species, which are non-native species whose introduction will cause or likely cause negative economic, ecological or human health effects. The Michigan Department of Natural Resources believes all species of Asian carp listed here (particularly bighead and silver carp) pose a significant threat to the biological community and recreational opportunities in the Great Lakes region.
What's being done to stop Asian carp?
The U.S. Army Corps of Engineers has built a pair of electrical barriers in the Chicago Sanitary and Ship Canal, a man-made canal that connects the Great Lakes to the Mississippi River via the Illinois and Des Plaines Rivers. These electrical barriers are used to prevent Asian carp from entering the Great Lakes Basin. Because recent environmental DNA (eDNA) testing indicated carp might have breached the electrical barriers, the Illinois Department of Natural Resources recently treated several areas near Chicago with rotenone, which is an organic compound used to kill any Asian carp that might have been in the area.
How is Michigan involved in this?
In December 2009, during maintenance of the electrical barriers that required the barriers to be turned off for a short period of time, a segment of the Ship Canal was rotenoned to eliminate all Asian carp in the area and prevent movement of fish through the area while the maintenance occurred. The Michigan Department of Natural Resources supplied rotenone and neutralizing chemicals to Illinois as well as sent a pair of Fisheries Division crews to participate in the rotenone treatment. Meanwhile, the Michigan Attorney General's office has been studying potential legal procedures to close the locks on the Chicago Sanitary and Ship Canal to prevent further migration of fish.
A permanent barrier or biological separation of the Great Lakes and Mississippi River Basins would prevent bighead and silver carp, along with other aquatic invasive species, from entering Lake Michigan at least via the shipping canal pathway.
What can the public do to help?
Asian carp are just one example of the potential problems caused by the unintentional translocation of aquatic invasive species. Recreational boaters and anglers should take all precautions to prevent transferring organisms from one body of water to another. Live wells, bilges and any other areas in a boat that hold water should be drained every time a boat is removed from a body of water. Those areas should also be washed and disinfected before the boat is returned to any body of water.
For additional information on preventing the spread of aquatic invasive species, check out the Keep Our Waters Great! Don't Dump Your Bait! campaign.