By Jim Hagerty
According to an Ohio State University professor, the potential threat of an Asian carp invasion in the Great Lakes has been wrapped in considerable hysteria and misinformation.
Although Asian carp, most notably silver and bighead, are capable of threatening native species, Konrad Dabrowski, an aquaculturist with the OSU School of Environmental and Natural Resources, says the fish are not capable of thriving in the Great Lakes.
While the fish continue to be a concern in parts of the Illinois, Mississippi and the Missouri rivers, wildlife officials have noted alarming stats, which Dabrowki claims have little or nothing to do with the hallowed lake ecosystem.
In the Mississippi and Illinois rivers, Asian carp make up approximately 90 percent of fish biomass. A 20-pound bighead was caught beyond a barrier near Lake Michigan in June, which leads some to believe the room the species is quickly running out of is prompting fish to move toward the Great Lakes. However, Dabrowski thinks otherwise.
“I’ve been working with the fish for 15 years,” Dabrowski said. “The fundamental question is whether Asian carp that enter Lake Michigan and subsequently other Great Lakes can reproduce. In other words, will they be able to maintain or increase their populations, and eventually out-compete the local and prized sport-fish populations?”
Dabrowski’s answer is, “No.” The professor said Great Lakes temperatures and their vast depths would prevent Asian carp from the invasion many fear. Dabrowski said silver and bighead carp are able to survive in the Great Lakes, however, would not reach optimum size or rob native species of food.
Asian carp were introduced to the United States more than 30 years ago when hatcheries and ponds planted them to control harmful vegetation. The fish have since escaped and have been a growing concern in many U.S. waters. Although swarms of carp are routinely reported, they have not been responsible for wiping out other species in the Illinois, Mississippi, Missouri or Ohio rivers.
The electric barrier near Chicago remains active to keep Asian carp out of Lake Michigan while the debate over closure of a major shipping canal is ongoing. The Chicago Sanitary and Ship Canal will be shut down between Oct. 4 and 8 while work on the underwater electric barrier is done.
In January, a lawsuit which would have closed the canal indefinitely, was denied.
From the Sept. 15-21, 2010 issue