Asian carp could threaten Great Lakes
Written by Cadillac News   
Thursday, 14 December 2006 07:42

Two electronic barriers separate Lake Michigan from the Chicago ship canal. If the barriers are breached, it could prove devastating to the Great Lakes region. The effort is underway to control the movement of two species of Asian carp, which are “knocking on the door,” according to Department of Natural Resources Fisheries Supervisor Tom Rozich.

The invasive species would pose a significant threat to the Great Lakes because they are capable of surviving in cold water, Rozich said. Secondly, they would compete directly with perch, alewives, smelt and any type of larval species that subsists on plankton.

“These fish are plankton eaters and they consume huge amounts of food when they get big,” Rozich said.

The species of carp can grow in excess of 100 pounds. They pose a unique threat to sportsmen because they are known to leap out of the water when disturbed by outboard motors, which can cause injury to people and their boats.

Rozich said the carp have overwhelmed some areas of the Mississippi River, where they were introduced.

“They can crowd out native species by out-competing for the plankton forage and by limiting recruitment,” he said.

So far, federal agencies have focused efforts on an electronic barrier. It has worked to date but one radio-tagged native carp managed to slip past the barrier.

Rozich has his own theory how the fish entered Lake Michigan. Because the canal has no current, the fish was likely stunned. Then, a passing barge caused turbulence, therefore pushing the carp beyond the threshold of the barrier.

The best bet, Rozich believes, is to undo what man has already done and fill the ship canal back in.

“My suggestion, to be 100 percent safe, is to fill in the ship canal and find an alternative means,” Rozich said. “Biologists really think it would impact the Great Lake ecosystem and not in a positive manner.”

Michigan Attorney General Mike Cox is urging the feds to add silver carp and largescale silver carp to a list of animals that cannot be imported into the country.

“The ecological and economic stakes for Michigan - and the entire Great Lakes region - are extremely high,” Cox said.

Asian carp are voracious eaters and reproduce quickly. They are known to out-compete native species for small organisms, which they feed on.

The carp can weigh in excess of 100 pounds and are known to leap out of the water when disturbed by outboard motors, causing injury to people and their boats.

Silver carp, one of the invasive species, escaped from fish farms and sewage treatment basins, entering the Mississippi and Illinois Rivers and are now threatening to enter Lake Michigan.
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