03-31-2004, 12:26 AM
Study suggests multiple deterrents to limit invading carp
![[Image: 31604_bigheadcarptn.jpg]](http://images.dnr.state.mn.us/news/releases/31604_bigheadcarptn.jpg)
Bighead carp caught in Lake Pepin.
Slowing the advance of Asian carp into the Upper Mississippi River Basin will require multiple deterrents that could include an acoustic barrier, expanded public outreach and more regulation, according to a new study commissioned by the Minnesota and Wisconsin departments of natural resources and the U.S. Fish and Wildlife Service.
The study was commissioned last fall, about the time a bighead carp was netted by a commercial angler in Lake Pepin. The bighead is one of four ecosystem-disrupting Asian carp species introduced into the United States about 30 years ago by fish farmers in southern states to control vegetation and algae blooms.
"The study supports our concerns and identifies options for slowing the upstream movement of these detrimental fish," said Lee Pfannmuller, director of the Minnesota Department of Natural Resources (DNR) Ecological Services division. "The next step is to evaluate options identified in the report and propose a set of recommended actions."
This will occur over the next several weeks in collaboration with the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers and other state resource agencies in the Upper Mississippi River Basin. FishPro, a national engineering firm with experience in designing fish barriers, drafted the study.
Two other Asian carp species, silver carp (which leap at the sound of boat motors) and black carp have not been found in the Upper Mississippi River. Free-roaming grass carp have been reported throughout the Mississippi River Basin and are known to spawn downstream of the Iowa-Missouri border.
Although electrical barriers have proven effective in stopping migrating fish, the report recommended against the option citing high initial construction cost, monthly operating costs and safety concerns.
The acoustic barrier, which is recommended in the study, projects sound through a curtain of bubbles that would be located downstream from a lock and dam. This might be one component of an integrated barrier system located downstream from a lock and dam that would cost several million dollars.
The system, along with construction of habitat and staging areas to hold fish downstream of the barrier, would cost between $8 and $12 million.
Based on the movement of Asian carp in the Mississippi River, the barrier would have to be in place within the next two years, according to the study.
A number of agencies provided input on efforts to stop exotic carp species, including DNR representatives from Minnesota, Iowa and Wisconsin as well as the U.S. Fish and Wildlife Service, the National Park Service, U.S. Army Corps of Engineers, United States Geologic Survey and the University of Minnesota.
"The Minnesota DNR has adopted a strong commitment to protect the state's natural resources," Pfannmuller said. "We hope to find a way to keep this detrimental invasive species out of the Upper Mississippi River Basin."
Bighead carp can weigh up to 100 pounds and silver carp are slightly smaller. Both fish have large heads with eyes set close to the mouth, giving them the appearance of swimming upside down. Both grass and black carp have elongated bodies with dark scales and can weigh up to 50 pounds.
Anglers who catch a bighead, silver, grass or black carp are asked to take it to their local DNR fisheries office. Sightings of Asian carp also should be reported.
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Bighead carp caught in Lake Pepin.
Slowing the advance of Asian carp into the Upper Mississippi River Basin will require multiple deterrents that could include an acoustic barrier, expanded public outreach and more regulation, according to a new study commissioned by the Minnesota and Wisconsin departments of natural resources and the U.S. Fish and Wildlife Service.
The study was commissioned last fall, about the time a bighead carp was netted by a commercial angler in Lake Pepin. The bighead is one of four ecosystem-disrupting Asian carp species introduced into the United States about 30 years ago by fish farmers in southern states to control vegetation and algae blooms.
"The study supports our concerns and identifies options for slowing the upstream movement of these detrimental fish," said Lee Pfannmuller, director of the Minnesota Department of Natural Resources (DNR) Ecological Services division. "The next step is to evaluate options identified in the report and propose a set of recommended actions."
This will occur over the next several weeks in collaboration with the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers and other state resource agencies in the Upper Mississippi River Basin. FishPro, a national engineering firm with experience in designing fish barriers, drafted the study.
Two other Asian carp species, silver carp (which leap at the sound of boat motors) and black carp have not been found in the Upper Mississippi River. Free-roaming grass carp have been reported throughout the Mississippi River Basin and are known to spawn downstream of the Iowa-Missouri border.
Although electrical barriers have proven effective in stopping migrating fish, the report recommended against the option citing high initial construction cost, monthly operating costs and safety concerns.
The acoustic barrier, which is recommended in the study, projects sound through a curtain of bubbles that would be located downstream from a lock and dam. This might be one component of an integrated barrier system located downstream from a lock and dam that would cost several million dollars.
The system, along with construction of habitat and staging areas to hold fish downstream of the barrier, would cost between $8 and $12 million.
Based on the movement of Asian carp in the Mississippi River, the barrier would have to be in place within the next two years, according to the study.
A number of agencies provided input on efforts to stop exotic carp species, including DNR representatives from Minnesota, Iowa and Wisconsin as well as the U.S. Fish and Wildlife Service, the National Park Service, U.S. Army Corps of Engineers, United States Geologic Survey and the University of Minnesota.
"The Minnesota DNR has adopted a strong commitment to protect the state's natural resources," Pfannmuller said. "We hope to find a way to keep this detrimental invasive species out of the Upper Mississippi River Basin."
Bighead carp can weigh up to 100 pounds and silver carp are slightly smaller. Both fish have large heads with eyes set close to the mouth, giving them the appearance of swimming upside down. Both grass and black carp have elongated bodies with dark scales and can weigh up to 50 pounds.
Anglers who catch a bighead, silver, grass or black carp are asked to take it to their local DNR fisheries office. Sightings of Asian carp also should be reported.
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