WASHINGTON, D.C. — Just as invasive Asian carp are heading closer toward the Great Lakes, federal officials said they will spend an additional $50 million this year on new tests and research designed to limit the species’ expansion.

The additional funding is earmarked primarily to determine the best ways to control movement of the fish and to catch and kill the prolific species that has invaded Illinois waterways in recent years.

In some spots along the Illinois River, bighead and silver Asian carp are so abundant that boaters are at risk because motors excite the fish and they jump in and out of the water constantly. Numerous boaters have been hit by the flying fish.

In 2002, federal and state officials installed an electric barrier fence within the Chicago Sanitary and Ship Canal about 37 miles southwest of the city’s downtown, and it has served as the primary wall blocking the carp from reaching Lake Michigan.

While the U.S. Army Corps of Engineers is in the process of completing a long-term study on suggested permanent ways of keeping the carp out of the Great Lakes – a study due to be completed before the end of the year – the federal agency is allocating an additional $50 million to new research to control the species.

This includes developing carp pheromones, chemicals used to attract mates, so that schools of fish may be drawn to certain areas to be netted and killed, as well as toxins that may only affect the Asian carp species.

“This strategy continues our aggressive effort to bolster our tools to keep Asian carp out of the Great Lakes while we work toward a long-term solution,” said John Goss, who leads the anti-carp effort behind the White House’s Council on Environmental Quality. “The 2013 framework will strengthen our defenses against Asian carp and move innovative carp control projects from research to field trials, to implementation.”

Since 2010, the federal government has spent more than $250 million on the fight to control the fish, which are voracious eaters of food sources for all fish, such as plankton, as well as being prolific reproducers. First introduced to the United States from China in the 1970s to help keep Southern states’ fish farm ponds clean of algae, the fish somehow escaped and made their way into the Mississippi River network of tributaries.

So far, the farthest north the fish have been discovered is in a lake near Joliet that is fed by the Des Plaines River, said Kevin Irons, program manager for the Illinois Department of Natural Resources’ aquatic nuisance species program.

But critics of the federal government’s actions toward controlling the species point out environmental DNA already has been discovered north of the electronic barrier in the Chicago River. No live Asian carp have been discovered, though.

“The DNA of these carp we are trying to get out is getting to places we didn’t expect. The most likely scenario is a live fish, but we certainly have not found a smoking gun,” said Marc Gaden, spokesman for the Great Lakes Fishery Commission.

Getting the Corps’ study completed and acted upon – including the possible construction of permanent dams to block the Chicago River from Lake Michigan – is critical, said David Ullrich, executive director of the Great Lakes and St. Lawrence Cities initiative.

“If they get into the lakes, once they’re there, it’s close to impossible to remove them completely. That’s why time is of the essence,” Ullrich said.