TOPICS > Science

Asian Carp Disrupts Life in Illinois Rivers

July 3, 2006 at 6:25 PM EST
LISTEN SEE PODCASTS

TRANSCRIPT

ELIZABETH BRACKETT: Tim Scott is a professional fishing guide on the Illinois River. Channel catfish are his specialty.

TIM SCOTT, Fishing Guide: This is what we try to catch up here.

ELIZABETH BRACKETT: But catches like this are becoming rare on this river because of thousands of large, ravenous newcomers.

TIM SCOTT: The other day, when I was here, you couldn’t catch a white bass, a sauger, a catfish, or anything else, because there are so many Asian carp up here.

ELIZABETH BRACKETT: Two invasive Asian carp species in the Illinois River are presently making life difficult for Scott, sports fishermen and recreational boaters.

The first is the silver carp, known for its spectacular and potentially dangerous jumps, jumps that foul motors, knock water-skiers off their skies, and land with a thud in the bottom of boats.

TIM SCOTT: That’s the nightmare fish right here. Out of the thousands that you see, there’s millions more that you don’t see. A lot of them are hanging deep. A lot of them are three to five times as big as this.

ELIZABETH BRACKETT: Scott throws out his net in search of gizzard shad, his preferred catfish bait. Instead, he hauls in the second Asian invader species.

TIM SCOTT: Yes, every three square foot’s got one of these. This would be the big-head carp here, not the silver. See how much larger the mouth is? See how big that is? And, if you look right down in the mouth, you can see how they’re filter feeders. See the — the plankton rakers right here?

And that’s what they do. They go through the water column, opening their mouth like this, flushing water through their gills, and collecting that plankton.

Asian carp has cut off food supply

ELIZABETH BRACKETT: Plankton, which are tiny, sometimes microscopic, animals and plants, usually provide food for small fish, which are then eaten by larger fish.

By devouring the bottom of the food chain, the Asian carp cut off much of the food supply for more commercially desirable species.

TIM SCOTT: What are you guys fishing for today?

MIKE MCGROGAN, Fisherman: Well, we're trying to fish for some white bass, just throwing some spoons and stuff (INAUDIBLE) But you end up snagging more -- more carp than anything.

They have gotten really thick this last -- last year. This last year's been -- been really, really bad.

TIM SCOTT: And bigger.

MIKE MCGROGAN: And bigger, yes.

TIM SCOTT: Lots bigger.

MIKE MCGROGAN: The one I just snagged was probably close to 20 pounds.

TIM SCOTT: Yes.

MIKE MCGROGAN: And that's probably a pretty average, prevalent size.

ELIZABETH BRACKETT: The big-head and silver carp were brought here in the 1970s by Arkansas catfish farmers to eat the overabundance of algae in their ponds. But they became a menace when devastating floods in 1993 flushed them out of their ponds into the Mississippi River, where they thrived.

Mike Conlin of the Illinois Department Of Natural Resources says, with no natural predators, there was no holding these carp back.

Carp might invade Lake Michigan

MIKE CONLIN, Director of Resource Conservation, Illinois Department of Natural Resources: Well, as they say, the -- the door was left open. The cow's out of the barn. And it's very difficult, once you get into a natural system like this. You can try to keep it out of other watersheds. But the Mississippi, you know, watershed is so huge. I mean, these fish are going up the Missouri River, up, you know, through Iowa, and up in the Dakotas, to Montana. I mean, that's -- I mean, that's where they're going right now.

ELIZABETH BRACKETT: Rivers in the Mississippi watershed connect to the Great Lakes. The biggest fear now is that the Asian carp will invade Lake Michigan and then move on to the other Great Lakes, the largest body of fresh water in the world.

MIKE CONLIN: It's very, very economic importance. It's a $5 billion industry per year, because of the -- the good fishing that occurs there, whether it's for perch, whitefish, in other lakes, smallmouth bass, walleye, the salmon and trout, fishing that's...

ELIZABETH BRACKETT: And it would destroy all that, you think?

MIKE CONLIN: It could possibly not only adversely affect it, but -- but diminish it greatly.

ELIZABETH BRACKETT: To try and keep invasive species out of the Great Lakes, the Illinois DNR and the Army Corps of Engineers built a temporary demonstration electronic fish barrier in 1992 on the canal that links the Illinois River to Lake Michigan.

Since it seemed effective, they poured millions into constructing a permanent electronic fish barrier.

The Army Corps' Chuck Shea:

CHUCK SHEA, U.S. Army Corps of Engineers: As a fish approaches from either side of the field and moves toward the middle, the electrical field becomes stronger. So, the intent is that, as a fish comes in, depending on how hardy they are, they might go a little bit further or a little bit less far, but, at some point, they realize that, if they keep moving forward, the shock keeps getting greater and greater. So, they turn around and go back, rather than cross entirely over the barrier.

ELIZABETH BRACKETT: But the use of the ladder has been delayed, because the shocks extended so far under water, they might have created sparks that could ignite flammable cargo on a passing towboat. Meanwhile, the old demonstration barrier is keeping the Asian carp away from the Great Lakes.

ORION BRINEY, Fisherman: See, there goes one. The waves -- you see that running there?

Catch carp the old-fashioned way

ELIZABETH BRACKETT: Another way to stop the Asian carp is the old-fashioned way: Catch them. A new market for the fish has made that very profitable for third-generation commercial fisherman Orion Briney.

ORION BRINEY: When I was raised up, you never heard of catching as many fish as we do now. You just never -- people will just think you're lying to them when you tell them anyway. You know, they just can't believe it, until they go see it. And then they just: My God, I can't believe all that's out there.

ELIZABETH BRACKETT: Briney and his stepson, Jeremy Fisher (ph), lay out two big nets, then round up their prey, sending them racing toward the strong nets.

ORION BRINEY: These are the kind we're after, right? You see them? See, watch them take off the boat here. You can see them shoot in the air. See? That's what we are -- on this side. We're going to catch some here now.

ELIZABETH BRACKETT: And, before long, the nets have snagged them by the hundreds.

ORION BRINEY: Man, they're hitting hard. Whoo-wee. It looks like a bad day for the fish and a good day for the fishermen, it looks to me like.

ELIZABETH BRACKETT: Briney and Fisher (ph) pull in 15,000 pounds of carp. They do it one by one, hard, exhausting work, but Briney says it's worth the effort. Last year, the 47-year-old Briney had the best year of his life, making just over $200,000. He hauls his catch to the

Schafer fishery in Thomson, Illinois, on the banks of the Mississippi, where he sells it for 18 cents a pound.

MICHAEL SCHAFER, Schafer Fisheries Inc.: It's a food source that's readily available for -- for a lot of different applications, I feel, from institutional sales, to even export sales to various places in the world, as well as a humanitarian food aid programs of the future.

ELIZABETH BRACKETT: Mike Schafer began processing Asian carp for fertilizer five years ago. Business has doubled every year since, as he has developed new markets, particularly in Asian communities from New York to Chicago to San Francisco.

MICHAEL SCHAFER: They buy the whole fish or part of the fish. Some places buy filets. Some buy it just the way it comes out of the water. Some buy just the heads.

ELIZABETH BRACKETT: Schafer processed two million pounds of Asian carp last year. Next year, they hope to process 10 million pounds of the fish. If they do, that will have significant impact, both an economic impact and an environmental impact.

But Mother Nature also may be fighting back. At the beginning of the summer, thousands of dead Asian carp were found floating in the Illinois river. Illinois DNR fish biologist Wayne Herndon first spotted the die-off, possibly the result of a still-unknown virus.

WAYNE HERNDON, Biologist, Illinois Department of Natural Resources: We started seeing large dead fish. And, on closer inspection, they were big-heads and silver carp up to 50 pounds floating in the river. And they appeared to have been dead for maybe a couple of days at that point in time.

ELIZABETH BRACKETT: How many?

WAYNE HERNDON: Thousands in a short stretch, perhaps two miles; 1,000 fish per mile, I would say, would be a good -- good number.

Virus could infect other fish

ELIZABETH BRACKETT: So far, only Asian carp have been found dead. But U.S. fish and wildlife biologist Eric Leis was cautious in his celebration.

ERIC LEIS, Biologist, U.S. Fish and Wildlife: You know, it would be good to kill the -- you know, the silvers and the big-head carp. But, you know, whenever there's a virus like that, you just have to be cautious, you know, because you never know when it could infect other fish.

ELIZABETH BRACKETT: Results of the tests won't be known for at least a month. But for those who have made a buck off the Asian carp, this is not good news.

ORION BRINEY: Well, I'm pretty concerned about it. You know, this is -- this is the best living I have ever had so far. So, I would like to keep it a while, if I could. Yes, I'm concerned about it.

ELIZABETH BRACKETT: Those who consider the Asian carp a menace don't care if it's a virus, an electrical barrier, or the fledging fish industry that stops the invasive species. They just hope something works.