Asian Carp making progress up the Mississippi - Fishermen caught 47-pound bighead carp in Lake Pepin last month
The end of the shipping season on the Mississippi River this year brings a brief relief for those concerned about Asian Carp. The locks are closed, meaning the invasive fish won't be able to cross the taller dams at least until barge traffic resumes in the spring.
There are four species of Asian carp that are of concern: bighead carp, silver carp, black carp and grass carp. Of those, bighead and silver carp are the most troubling, said Irene Jones, river corridor program director for Friends of the Mississippi River. Grass carp aren't as detrimental to the environment, and black carp haven't made it north of the Iowa/Missouri border yet.
The problem with the fish is that they eat things like plankton, snails and other small organisms at the bottom of the river's food chain. Because of their large size, they can quickly out-eat other native species that also depend on the small organisms for food.
"They kind of topple the food chain by eating copious amounts of (food)," Jones said.
The other problem is that Asian carp reproduce in large numbers, so an area could see a few pioneers one year and have a massive population just a couple years later, Jones said.
Bighead and silver carp have both been found in Minnesota waters in the past couple years. A bighead carp was caught near Prescott in April, 2011. A silver carp was caught in Winona last March.
The summer didn't produce any of the fish, but in November, a bighead carp was netted by commercial fishermen in Lake Pepin. The carp was one of the biggest seen this far north so far, weighing in at 47 pounds.
"They are moving up," Jones said. "So it's a concern. There's been a lot of alarm bells going off, because it does kind of creep up on the river quickly."
The Lake Pepin fish's size doesn't necessarily mean Asian carp are getting a foothold here just yet. It's actually the juveniles that concern the Minnesota DNR more, Jones said. While large fish are breeders, finding a juvenile means that the carp are already breeding.
Stopping the spread
State and local agencies, preservation organizations and individuals have been working with state and federal lawmakers to try to come up with a solution to keep Asian carp from populating the upper Mississippi. So far, though, nothing has been put in place.
The Minnesota DNR wants to be able to close Lock 1 in Minneapolis once an adult Asian carp is found in Pool 2 (upstream of Lock and Dam No. 2 in Hastings) and a juvenile is found in Pool 4. But the move is controversial because closing the locks could put a damper on some industry. The locks are also controlled by the Army Corps of Engineers, and under current legislation, the Corps can't close a lock without the approval of the U.S. Congress. Federal legislation hasn't gone anywhere yet, but the discussion has started, at least.
"We're not there yet, but we're closer," Jones said.
Agencies and organizations are looking into deterrence options such as sound or bubble barriers to discourage Asian carp from advancing upstream. One possible location for a bubble barrier is at the mouth of the St. Croix River in Prescott.
A consultant has been hired to study the feasibility of installing a barrier at Lock and Dam No. 1, Jones said.
While officials work toward a more permanent solution, those who use the river recreationally are being asked to do their part, Jones said, by enjoy the features in their pool without traversing the locks.
Anyone who sees or thinks they see any Asian carp should report it to the DNR. More about Asian carp can be found online at www.dnr.state.mn.us