EAST LANSING, Mich., Oct. 17 (UPI) -- U.S. researchers who have used sex to try to control the fish-killing sea lamprey in the Great Lakes, say death will also be used, in the form of necromones.
Previously, researchers have used lamprey sex pheromones to attract the eel-like bloodsucker into certain rivers and streams to be destroyed by lamprey-specific poisons, the Milwaukee Journal Sentinel reported Sunday.
Researchers at the University of Michigan say they can now use the powerful sense of smell of the creatures to both pull and push the lampreys to their fate by combining the attractive properties of lamprey sex pheromones with the repellent action of the odor of dead and dying lampreys.
"They're like a big swimming nose ... so they are very good at detecting odors, and that affects their behavior," Marc Gaden of the Great Lakes Fishery Commission said. "Some odors attract, like pheromones. And some repel, like necromones."
Researchers say they stripped the flesh from decaying lampreys, put it in solution, and then pumped it into a tank full of live lampreys where the found the strong repellent action could be used to "herd" the lampreys in the desired direction.
Scientists say they're working on a system to dispense a dose of the dead lamprey concoction into a stream to guide lampreys into a "killing zone" where they can be eliminated with poison.
An 18-inch-long lamprey adult lamprey can destroy as much as 40 pounds of fish during the 12 to 20 months it spends in open lake waters as an adult, researchers said.