Asian Carp can grow up to 110 pounds (Photo courtesy of the US Fish and Wildlife Service)
There are invasive fish swimming their
way toward the Great Lakes. If they get in,
they could swallow up a multi-billion dollar
sport fishing industry. Mark Brush reports,
officials are investing millions of dollars
to keep Asian Carp out of the Great Lakes:
Transcript
There are invasive fish swimming their
way toward the Great Lakes. If they get in,
they could swallow up a multi-billion dollar
sport fishing industry. Mark Brush reports,
officials are investing millions of dollars
to keep Asian Carp out of the Great Lakes:
Asian Carp were imported by fish farms in Mississippi and Arkansas to control algae.
But the fish escaped during floods. They swam out of the fish ponds, and into the Mississippi
river. And they’ve been moving north ever since.
(sound of boats)
Thad Cook is on a tributary of the Mississippi River in Illinois. This river is more than
400 miles upstream from where Asian Carp first escaped the fish farms.
Cook is looking
for two types of Asian Carp known as Silver and Bighead Carp. It turns out t’s not hard to find them. He dips an electrified pole into the water – and the fish jump right out of the
river and into the boat.
(sound of fish flopping in boat)
Cook is with the Illinois Natural History Survey. His group, along with several others,
has been making trips like this one for years. They’ve been keeping a close eye on where
the fish are going. He takes a guess at how big this fish is.
“No he’ll go… uh.. he’s probably…”
“Hold him out there Jimmy!”
“Yep, six, seven, eight, nine, ten pounds.” (Laughter)
His fish story could have gone a lot further. Some types of these Carp can get up to a
hundred pounds. There aren’t many fish that can compete with an appetite like that.
Biologists are finding that these carp are pushing native fish species aside as they spread
north through the Mississippi River system. And some fear it’s only a matter of time
before they swim their way into the Great Lakes.
David Jude is a fisheries biologist with the University of Michigan.
“I’m very concerned about what impact they would have in the Great Lakes because
they’re planktovores which means they filter zooplankton from the water column. And, they’re just huge fish. And so they have the potential for having
a tremendous impact on our ecosystems.”
He says the silver and bighead carps are filter feeders. They pass up eating smaller fish –
and head straight for the bottom of the food chain.
Jude says if Asian carp get in, it’ll make a bad situation worse. The Great Lakes are
already losing zooplankton from other invasive species. Asian Carp could
destroy a 4 billion dollar a year sport fishing industry.
(sound of canal)
And here is where the battle line is being drawn. The fish have been spotted thirty miles
downstream from this spot on the Chicago Ship and Sanitary Canal. A century ago,
engineers blasted through solid rock to connect the Great Lakes with the Mississippi
River system.
Chuck Shea is with the U.S. Army Corps of Engineers.
“Any type of fish that would want to move between Lake Michigan and the Mississippi
river basin – has to pass through the Chicago Sanitary and Ship Canal – there’s no other way to swim through. So, they have to come through this body of water we’re standing in front
of right now.”
Shea is in charge of the construction and maintenance of two electric fish barriers along this canal.
When this barrier is online, machines will pulse electricity into the water. The electric current shocks
the fish – making them swim away.
This barrier hasn’t been turned on yet. There have been delays due to funding shortages. And they’re still
doing safety testing with the Coast Guard.
Right now, the only thing that would keep the carp from getting into the Great Lakes is a temporary electric
barrier built six years ago.
The good news is that there still seems to be a little time. Biologists say, so far, Asian Carp haven’t moved any
closer than thirty miles from the barrier for the last couple of years.
For The Environment Report, I’m Mark Brush.