New Bubble Barrier to Repel Asian Carp?

The Asian carp is threatening to invade the Great Lakes. Right now there’s an electric barrier in the Chicago canal to stop the fish from getting into Lake Michigan, but a new study shows it’s not 100-percent effective. As the Great Lakes Radio Consortium’s Annie Macdowell reports, scientists are working on a second line of defense…bubbles:

Transcript

The Asian carp is threatening to invade the Great Lakes. Right now there’s an
electric barrier in the Chicago canal to stop the fish from getting into Lake
Michigan, but a new study shows it’s not 100% effective. As the Great Lakes
Radio Consortium’s Annie Macdowell reports, scientists are working on a second
line of defense – bubbles.


In a recent experiment by the Illinois Natural History Survey, a startled Asian
carp swam straight through an electric field like the one in the Chicago Canal.


The International Joint Commission is bringing specialists from Britain to build
an experimental acoustic bubble barrier and test it on the Asian carp. It works
like this: a pump filled with air and sound expels bubbles with sound trapped
inside.


Bill Moy of the Wisconsin Sea Grant says the process creates a nearly seamless
barrier.


“If you just project sound into the water, it’s not like a wall of sound. But by
entraining the sound in this bubble, you can actually create a wall of sound in
the water that’s much more uniform.”

Moy says the infrasound inside the bubbles is like an idling truck – you can feel it
more than you hear it.


The fish can’t find a break in the sound, so they turn around.


The International Joint Commission says if they decide to install the bubble
barrier, it won’t be until the spring.


For the Great Lakes Radio Consortium, I’m Annie MacDowell.

Battle Plans for Asian Carp

Asian carp are the new poster fish in the campaign against invasive species. For years, foreign invaders like the zebra mussel, the round goby, and now the carp have been threatening the ecosystem of the Great Lakes. Like their fellow species of concern, the carp have no natural predators to keep their numbers in check. Ecologists report that they are now closing in on Lake Michigan from the Mississippi and Illinois rivers. This has authorities in the U.S. and Canada stepping up efforts to control them. The Great Lakes Radio Consortium’s Diantha Parker reports:

Transcript

Asian carp are the new poster fish in the campaign against invasive species. For years, foreign invaders like the zebra mussel, the round goby, and now the carp have been threatening the ecosystem of the Great Lakes. Like their fellow species of concern, the carp have no natural predators to keep their numbers in check. Ecologists report that they are now closing in on Lake Michigan from the Mississippi and Illinois rivers. This has authorities in the U.S. and Canada stepping up efforts to control them. The Great Lakes Radio Consortium’s Diantha Parker reports:


The Asian carp now in the spotlight are the silver and bighead varieties, and they share traits that worry environmentalists.


For one thing, they’re large…sometimes reaching up to a hundred pounds in less than three years. They escaped from fish farms in Mississippi about twenty years ago, and have been making their way up the Mississippi River ever since.


The carp voraciously consume the same microscopic organisms that native fish depend on.


They’ll out-eat anything in their midst. That means game fish won’t have as much to eat, and their populations will suffer.


And the carp are invasive in other ways, too. At a recent news conference a few yards from Lake Michigan, journalists and curious passersby inspected three enormous dead carp laid out on a folding table…glistening in the sun next to Pam Theil, a project leader at the U.S. Fish and Wildlife Service.


“It sounds sensational, but they can jump out of the water into your boat. A gentleman who works for the Illinois Natural History Survey has gotten hit four times, the last time he had to file for workman’s compensation with a neck injury. A commercial fisherman on the Caskaskia River got his nose broken. And there are reports of people on the Caskaskia, who are going out fishing, or just recreation in their boat…they’re taking cookie sheets with them to act as a shield, so that they don’t get hit.”


The newest weapon in the Great Lakes Fight against the carp is an electronic barrier.
It was built in April by the Army Corps of Engineers and the International Joint Commission, an organization that oversees the use of waterways between the U.S. and Canada.


The electronic barrier sits in the Chicago Sanitary and Ship Canal about 30 miles downstream from the city. The Canal is a manmade link between Lake Michigan and the Chicago River. This particular spot was chosen for the barrier because it’s a revolving door between the Great Lakes and the Mississippi River basin.


The barrier itself consists of about one hundred and sixty wires, spaced a few feet apart, that lie crosswise along the bottom of the canal. The wires emit electrical impulses to deter all fish that approach them.


“There is a charge that is applied to those cables.”


Dennis Schornack is U.S. chairman of the International Joint Commission.


“Not a real strong charge, not one that would be harmful to people, if they fell into the
canal, but strong enough for fish to sense it, and when they sense this charge in the water they turn, and turn back down the river.”


Right now, the electronic barrier is only in an 18 month test phase. The authorities involved say after that time is up, funding from Congress will be needed to keep it in operation.


Some people wonder why we can’t just catch these invasive carp and eat them. But while the carp are a popular food source in Asia, they’ve been slow to catch on here, says Pam Theil.


“I think that there is a mentality that we’d rather be eating walleye or something than carp.”


But a chicken processing plant in southern Illinois has looked into processing the carp…they’ve taste tested it as a product similar to tuna, but are still deciding whether it’s marketable.


For the Great Lakes Radio Consortium, I’m Diantha Parker.

Asian Traditions May Spread Invasive Carp

Biologists say the invasive Asian carp is knocking on the door of the Great Lakes as populations of the imported fish make their way up the Mississippi River system. And while officials are seeking funding to construct and maintain an electric barrier to keep the fish out, the Great Lakes Radio Consortium’s Mark Brush reports that the fish has another way of getting into the lakes:

Transcript

Biologists say the invasive Asian carp is knocking on the door of the Great Lakes as populations of the imported fish make their way up the Mississippi River system. And while officials are seeking funding to construct and maintain an electric barrier to keep the fish out, the Great Lakes Radio Consortium’s Mark Brush reports that the fish has another way of getting into the Lakes:


Two years ago an Asian carp was netted in Lake Erie. And another was found
in a fountain in downtown Toronto. These fish were more than likely released
by humans. And while biologists have not yet found evidence of an
established population of Asian carp… they fear more releases like these
could lead to the spread of this harmful fish.


Dennis Schornack is the U.S. Chair of the International Joint Commission, a
governmental body which monitors the waters between Canada and the U.S. He
says that certain traditions of Asian immigrants may be unknowingly contributing to the problem:


“We are advised that there are certain customs in the Asian community which
involve not only eating the fish, but giving the fish back to the source, so
that it’s sort of, ‘buy two, eat one, return one.'”


Schornack says that the governments of Canada and the U.S. should educate
those who buy Asian carp for food about the threat the fish pose to the
Great Lakes ecosystem. For the Great Lakes Radio Consortium, I’m Mark
Brush.

Black Carp Introduction Gets Hooked

States in the Mississippi river basin are protesting a decision by the state of Mississippi to allow a foreign fish to be introduced tocontrol a pest. The Great Lakes Radio Consortium’s Lester Graham reports… the other states are concerned the fish will escape into the wild and damage the environment:

Transcript

States in the Mississippi River Basin are protesting a decision by the state of Mississippi to

allow a foreign fish to be introduced to control a pest. The Great Lakes Radio Consortium’s Lester

Graham reports the other states are concerned the fish will escape into the wild and damage the

environment:


If you buy a package of catfish filets at the supermarket or order blackened catfish at your

favorite restaurant, chances are that fish was raised in a farm pond in Mississippi. The state of

Mississippi supplies almost three-fourths of the world’s commercial catfish. It’s a two-billion

dollar a year business, coming in only after cotton and timber as one of Mississippi’s largest

industries.


In recent years, Mississippi farmers have been struggling with a parasite that’s attacking the

catfish. Jimmy Avery is a researcher with the National Warmwater Aquaculture Center at Mississippi

State University. He says the parasite is causing quite a bit of damage.


“It’s either killing these fish outright or it’s stressing them to the point they no longer grow.”


Avery says the parasite makes its home in snails. To get rid of the snails, the Mississippi

Department of Agriculture and commerce has approved introducing an Asian fish called the black

carp. The black carp eats snails and mussels. But, other states are worried that the black carp

will escape the farm ponds and get into the wild. Avery says that’s not likely…


“The Mississippi Department of Agriculture and Commerce has decided that through the permit

process, we can minimize this. They’ll know where every black carp is located. They’ll know what

kinds of system they’ve been put in and it felt like that those regulations that had been put in

place are strong enough to prevent that.”


But the State of Missisippi’s assurances don’t convince others. Roger Klosek is the Director of

Conservation at the Shedd Aquarium in Chicago. He studies native mussels.


“If black carp are used to deal with the snail problem, eventually they’ll escape into the main

waterways, and start reproducing. And once they do that, they’ll start feeding on the native

mussel fauna which is one of the last remaining native mussel faunas in the United States and

literally wipe it out.”


Klosek says native mussel populations have already been hurt by another exotic species, the zebra

mussel. He believes the black carp would be the last straw for American freshwater mussels.


“So, somebody’s going to lose and it’s probably better – I know the catfish farmers will hate me

for saying this, but – it’s probably better that they lose a little economically rather than

reduce some of the native fauna to an irretrievable state.”


Some states’ officials agree with Klosek. Bill Bertrand works with the Illinois Department of

Natural Resources fisheries office. He says there’s a history of Asian carp getting loose. The

silver carp, the bighead carp, and the grass carp have already escaped from farm ponds, mostly

from Arkansas where there are few regulations.


“There’s a history of these exotics, imports, escaping into the river system, spreading throughout

the entire river basin system and causing impacts on all the other states in the system. And

Mississippi appears to tend to ignore that fact and go ahead their own merry way, saying ‘Well

we’re doing this because we want to do it and it’s beneficial to us.'”


Bertrand says governors of some of the states along the Mississippi River have sent letters to the

Governor of the State of Mississippi, asking him to stop the use of black carp. Several of the

states intend to ask the U.S. Fish and Wildlife Service to ban the importation of the fish. The

federal agency has not yet received that request… but even if the Fish and Wildlife service

found a ban was appropriate, it would take several months to go through the process. Even then, a

ban would not apply to black carp already in the U.S.


Mike Oetker is a fisheries biologist with the Fish and Wildlife service. He says the agency is

trying to play the role of mediator.


“Right now the U.S. Fish and Wildlife Service is trying to work with states and the industry to

try to prevent the problem of the possible release or accidental release of black carp into the

environment. There are several alternatives to black carp where we can use native fish such as the

red ear sunfish or freshwater drum or even big mouth buffalo to do the same type of biological

control that the black carp are doing. And that would give of the ability to kind of circumvent

this problem.”


The catfish farmers in the State of Mississippi say the native fish don’t eat the snails as

quickly as the black carp. The Mississippi Department of Agriculture and Commerce says it will ask

farmers to use chemical treatments first and where native fish will work, they’ll try to use them.

but in the end, the Mississippi agency says it will allow catfish farmers to use black carp when

it appears other methods don’t work.


For the Great Lakes Radio Consortium, this is Lester Graham.