Asian Carp can grow up to 110 pounds (Photo courtesy of the US Fish and Wildlife Service)
A stronger electric barrier
to keep an invasive fish out of the
Great Lakes is set to be turned on.
But people who travel past the
underwater barrier are worried about
electric shocks. Chuck Quirmbach
reports:
Transcript
A stronger electric barrier
to keep an invasive fish out of the
Great Lakes is set to be turned on.
But people who travel past the
underwater barrier are worried about
electric shocks. Chuck Quirmbach
reports:
This barrier is supposed to keep Asian carp from getting into the Great Lakes.
Those fish escaped from Southern fish farms years ago. They’ve spread up the Mississippi river.
Now they’re near a canal that connects the Mississippi system with the Great Lakes.
Biologists worry the big fish would ruin Great Lakes fishing and the Lakes’ ecosystems. Start up
of ‘The Stronger Barrier’ was delayed because of concerns the electric current could hurt crews
on barges and people on recreational boats as the vessels passed by.
U.S. Coast Guard Captain Bruce Jones recently gave thumbs-up to running the new barrier at
low power.
“ We believe it will continue to keep the Great Lakes protected from carp through the winter, until
spawning season starts.”
But biologists don’t think the barrier will work well enough at low power. And barge operators
don’t want it on at all. They’ll be discussing the concerns at a meeting in Chicago in January.
Natural resources workers wade in the Vermillion River, 30 minutes south of Minneapolis. They're sending mild shocks through the water to capture trout and measure them. (Photo by Stephanie Hemphill)
Brian Nerbonne is a trout habitat expert with the Minnesota Department of Natural Resources. He says when developers minimize the flow of warm stormwater into streams, it can help trout survive and flourish. (Photo by Stephanie Hemphill)
The trout in the Vermillion River grow quickly, because they have other fish to eat. (Photo by Stephanie Hemphill)
Suburban growth typically degrades
the quality of rivers and lakes. But
developers are finding ways to protect
water quality even as they build housing
developments and malls. Stephanie Hemphill
reports on a stream in a major metropolitan
area that still has trophy-sized native
trout in it – and how people are working
together to protect the trout:
Transcript
Suburban growth typically degrades
the quality of rivers and lakes. But
developers are finding ways to protect
water quality even as they build housing
developments and malls. Stephanie Hemphill
reports on a stream in a major metropolitan
area that still has trophy-sized native
trout in it – and how people are working
together to protect the trout:
A half dozen people in waders stand nearly waist-deep in a bend of
the Vermillion River. They’re getting ready to send electric shocks
through the water.
(sound of gas motor starting)
They’re looking for trout.
They’re stunning the fish so they can catch them in nets. When they
have about ten fish of all sizes in their bucket, they pull their boat to
the side to count and measure them.
“You can see on the one he’s pulling out right now, it’s a male, it’s got
that big hook jaw on the front. 532. These are millimeters; that’s
about 21 inches. ”
Brian Nerbonne is a trout habitat specialist with the Minnesota
Department of Natural Resources, and today he’s a happy man. He’s
collecting a healthy batch of trout on this river just thirty minutes from
downtown Minneapolis. He figures the big ones they’re finding are
about six years old.
“Fish grow really fast in the Vermillion: you saw when we were
shocking there’s a lot of a other fish, suckers, creek chubs, and things
like that they can eat, they grow a lot faster eating those other fish
than if they were just eating bugs.”
Biologists regard trout as a kind of canary in the coal mine. These
trout are healthy, and that’s a sign that this river is healthy for all
kinds of animals, including people.
As you walk along the stream, you can see schools and houses and
roads literally a stone’s throw from the river. Typically, development
like this threatens the trout, because it produces warm, dirty storm
water runoff.
Twenty years ago, a local sportsmen’s group asked the state to
designate parts of the Vermillion River as a trout stream. That would
mean local governments would have to do more to protect the water
quality, and not all of them were happy with the idea.
State planner Michele Hanson had the task of coaxing local officials
to get on board.
She did that by doing what the DNR is doing today – shocking the
river to show local officials there was something there worth
protecting.
“Once everyone believed us that it’s trout stream, then we went out
and met with every community along the river, of the section that we
were going to designate as trout stream, to tell them what it would
mean to them, what changes might happen.”
It would mean every town, every township and county that the river
flowed through would have to make some changes in the way they
developed.
Now, in some sections of the river, builders must leave a buffer to
protect the stream, as much as 150-feet wide.
Also, they need to avoid increasing the amount of runoff. Rainwater
that sheets off roads and driveways and rushes directly into the river
is too warm for the trout.
Builders are learning how to get the water to soak into the ground
instead. They can build narrower streets and shorter driveways.
They can build rain gardens and other landscaping that holds the
runoff long enough that it can soak in.
The state is also building structures in the river to provide better
hiding places and spawning grounds for the trout.
(sound of counting fish)
It’s all aimed at holding onto a rare treasure – a healthy trout stream in
a major metropolitan area.
For The Environment Report, I’m Stephanie Hemphill.
Some scientists say they’ve got a new answer to a centuries-old problem with ships. The problem is called “bio-fouling.”
That’s when ships pick up unwanted marine life on their hulls, such as mollusks and barnacles. Brian Bull reports on a shocking solution:
Transcript
Some scientists say they’ve got a new answer to a centuries-old problem with
ships. The problem is called “bio-fouling.” That’s when ships pick up unwanted
marine life on their hulls, such as mollusks and barnacles. Brian Bull reports on
a shocking solution:
Researchers at the University of Wisconsin-Madison say coating boat hulls with
thousands of tiny, titanium electrodes will help stop marine organisms from
sticking onto watercraft. Initial tests show that electrodes slow build-up of
marine life by up to 50 percent. They gently zap any critters that come close to
the hull.
Scientist Dan Noguera says not only can this help curb the spread of invasive
species such as zebra mussels, but it can also help maintain a ship’s fuel
efficiency:
“If you have a surface that has a lot of bio-organisms attached, it’s going to slow
down the boat. You need to put a lot more fuel into it. So there are economic
impacts of these fouling agents.”
Besides wasting fuel, some of the hitch-hiking invasive organisms are causing
environmental damage.
Asian Carp can grow up to 110 pounds (Photo courtesy of the US Fish and Wildlife Service)
