Break in the Great Lakes Food Web?

A major link in the food web is disappearing from the Great Lakes. Researchers are concerned that its absence will damage fish populations. The Great Lakes Radio Consortium’s Lester Graham has more:

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.


A New Indicator for Global Warming?

Researchers in Wisconsin have identified a species of dragonfly never
seen in the state before. They’ll be watching it as a possible
indicator of global climate change. The Great Lakes Radio Consortium’s
Stephanie Hemphill reports:

Sediment Plume Carries Life to Lakes

  • The USEPA research ship Lake Guardian. (Photo courtesy USEPA Great Lakes Program Office)

For the second year in row, government scientists plan to be onboard a ship
chasing a natural phenomenon on Lake Michigan. The Great Lakes Radio
Consortium’s Lester Graham reports a sediment plume might be the key to all
life in the lake:

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