Asian Carp & the Great Lakes: Other Pathways for Carp (Part 3)

Sep 12, 2012

Today, we continue our week-long series on Asian carp and the Great Lakes.

Most of the efforts to keep bighead and silver carp out of the Great Lakes are focused on the shipping canals in the Chicago area.  But there are other ways the carp could get into the Great Lakes.

The U.S. Army Corps of Engineers is looking at more than a dozen other possible watery routes carp could take.

A couple weeks ago, I went to see the site that many scientists consider the 2nd highest risk pathway for carp.  It’s a sleepy little place called Eagle Marsh.  It’s more than 700 acres and it’s bone dry right now, with not a carp in sight.

So it’s a little strange when you first see the 8 foot tall chain-link fence. It stretches from one side of Eagle Marsh to the other.

“This fence is designed to stop Asian carp but as you can see when you pan around and look at the rest of this fence the fence is built on dry ground.”

Doug Keller is with the Indiana Department of Natural Resources.

“This is an area that floods when the Wabash and Maumee systems, they can flood together, and this is the area they flood together and this is the potential pathway that Asian carp can move from the Wabash River up toward the Maumee River.”

Keller says there are bighead carp about 20 river miles away from this marsh in the Wabash River.  The concern is – if carp get into the Maumee River, they could swim right to Lake Erie.  

“There have been many people that have assessed the risk of Asian carp getting into the Great Lakes system, and certainly should they get into Lake Erie almost any expert would agree that’s probably the place in the Great Lakes they would do the best.”

This fence is a temporary barrier. It was built to block adult carp from getting through... but not baby carp. 

“Any fish that’s probably six inches or less, of any kind of fish, is going to be able to slide right through this fence, but the juvenile Asian carp live in backwater areas.  So they’re going to hatch and go off into those backwater areas in the middle and lower Wabash River and they’re going to be 100 miles, easy, from here.”

Keller says even if Asian carp laid eggs in the upper Wabash River... those eggs would get sent on a 60 mile drift downstream, far from this spot in Eagle Marsh.

So far, the fence has lived up to at least one big test. 

Betsy Yankowiak is the Director of Preserves and Programs at the Little River Wetlands Project. Her group is one of the owners of Eagle Marsh, and they have a contract to inspect and maintain the carp fence.  She says a year ago in May there was so much rain, she had to take a canoe out to the fence.

“When we got out there, these common carp were swimming on both sides of the fence and I got out of the canoe, and I have my big knee-high boots on but still, common carp mouths... and they were floating around by my feet and I was like oh, man.”

Common carp have been in the U.S. since the late 1800's... so they’re not the kind of carp they’re trying to stop here.

But Yankowiak says she’s keeping an eye on the carp fence... just in case any bighead or silver carp make a run for it in the future.

“If Asian carp cross, it’s on me. So I want to make sure we’re doing the best job we possibly can.”

But even if the carp fence works... or the carp never get close to Eagle Marsh... biologists say there are other ways carp could get into the Great Lakes.

People still move live Asian carp around the region even though it’s illegal. It’s possible those fish could get into the Lakes.

And... experts say baby Asian carp look a lot like bait fish called gizzard shad... so fishermen could release them accidentally.

Our series continues tomorrow with a look at what might happen if carp get comfortable in the Great Lakes. 

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