Sunday, December 25, 2011
Feds List Possible Methods for Blocking Asian Carp
Federal officials said Wednesday they were evaluating dozens of options for stopping Asian carp and other invasive species from crossing between the Great Lakes and Mississippi River systems and doing environmental harm in their new surroundings.
The U.S. Army Corps of Engineers released a report listing more than 90 options for blocking the path of would-be aquatic migrants, including poisoning sections of waterways, installing devices that emit light and sound waves, and inducing genetic changes to prevent organisms from reproducing.
The report did not indicate which controls the Army Corps might prefer or evaluate their effectiveness or potential cost. Project manager Dave Wethington said experts will pare down the "shopping list" to determine which methods are likely to work best. They will accept public comments from Dec. 21 to Feb. 17.
"It's very important that we cover all the possible combinations of technologies," said John Goss, the Obama administration's Asian carp program coordinator.
Among the alternatives is installing barriers or other structures to sever the century-old, man-made link between the two systems near Lake Michigan in the Chicago area. That method is preferred by Michigan, Wisconsin, Minnesota, Ohio and Pennsylvania.
Those states are suing the federal government, demanding quicker action to prevent Asian carp from reaching the Great Lakes, and disrupting their fishing industry by gobbling up plankton needed by other organisms in the food web.
Illinois and Chicago-area business interests say cutting the artificial link would disrupt waterborne commerce and kill jobs.
Goss said an electric barrier network on a shipping canal southwest of Chicago is preventing Asian carp and other fish from swimming northward toward Lake Michigan. No bighead or silver carp — the two Asian species threatening to attack the lakes — have been found beyond the barrier this year, although their genetic material continues to turn up in water samples there. The Army Corps strengthened the barrier's electric pulses this fall.
Still, Goss said the barrier was designed to deter fish and wouldn't necessarily prevent other organisms from getting through. Earlier this year, the Army Corps released a list of 38 other invasive species that pose a risk of slipping between the Great Lakes and the Mississippi, including several types of algae, crustaceans such as the spiny water flea, mollusks and plants.
The Corps also is looking at 18 other waterways from New York to Minnesota that could provide pathways between the two watersheds.
Some of the technologies in Wednesday's report are already in use, including fish and plant poisons and stepped-up harvesting by commercial fishermen. Others are still under development.
Among the possibilities are creating high-velocity waterfalls to block upstream passage, zapping species with ultraviolet light or ultrasound, sucking oxygen from the water or raising its temperature to lethal levels, and using biological repellents or pheromones to lure invaders to places where they could be trapped or killed.
The Army Corps will report to Congress on its findings in late 2015 or early 2016, said Gary O'Keefe, invasive species program manager for the Great Lakes.
Federal officials have said previously the study would be completed in 2015. The possibility of a delay into the next year drew criticism from John Sellek, spokesman for the Michigan attorney general's office.
"They can't even maintain their own snail's pace in fighting a fish," Sellek said.
A spokeswoman for the White House Council on Environmental Quality said the timetable had not changed.