August 22, 2012 - As seen in this Your News Now clip from mid-July, there is concern over an invasive fish species that could have a strong impact the Great Lakes ecosystems.

A possible invasion into the Great Lakes of several of the seven species of carp found in North America, but not in the Great Lakes – the silver and bighead carp (known collectively as Asian carp) – has caught the interest of New York Sea Grant's Fisheries Specialist David MacNeill and NYSG’s Coastal Education Specialist

Helen Domske. So much so that MacNeill and Domske produced a fact sheet this past winter entitled Asian carp: Threats to the lower Great Lakes and St. Lawrence River? (pdf).

“This fish is a threat because it is very prolific – it breeds very readily, and there are places in its range along the Mississippi River and the Illinois River where it is now the dominant fish species,” said Domske.

The fish were imported into U.S. South in the 1970s, found their way into the Mississippi in the 90s, and started swimming north.

"In essence, knocking on the door because they're very, very close to Lake Michigan and once they get into the Great Lakes, we can't just turn around and send them back," Domske said in the YNN segment.

Scientist believed hundreds of these fish would need to cross electronic barriers set up near Chicago to start a self-sustaining population in the Great Lakes, but, as pointed out in the YNN segment, a new Canadian study suggests otherwise.

"If they're in a small area of the lake, like a little embankment, even if there are just ten or twenty of them, they could reproduce and their eggs float," said Domske.

Asian Carp can grow to be more than a hundred pounds and compete with native fish for plankton.

“Asian carp are filter feeders," Domske explained. "And like the mussels, these carp love to eat plankton. And when I say plankton, keep in mind that all fish start out as a type of plankton.”

"Everything in the lake depends on what's going on in the planktonic community and if they're filtering all that out, they're taking that away," Domske added.

Added MacNeill, “Plankton are the energy sources that drive much of the open water food web and are the only food for fish larvae and species like alewife.” Alewife are the plankton-eating fish that are preferred prey for predatory fish like trout and salmon. The big question,” says MacNeill is: “If the carp get into the Great Lakes, could they affect the multimillion dollar trout and salmon fisheries?”

Silver carp, noted for their high-flying jumping behavior, have also seriously injured people aboard watercraft.

"People have had their noses broken," she said. "People have been knocked off jet skis. People have been injured. They've jumped in boats."

Both Domske and MacNeill agree that if Asian carp get into one of the Great Lakes, there would be nothing to stop them from moving throughout all of the Great Lakes. “We may not be able to get rid of the invasive species that have already entered the system, but we need to make sure that we do all that we can to prevent the carp from getting in,” said Domske.



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