Sea lampreys are an invasive species in the Great Lakes. They have no jaw, but have an oral disk that attaches to fish and sucks their blood, said Li, an MSU fisheries and wildlife professor.

“It’s a very inhibiting factor in the Great Lakes,” he said.

Li has studied lampreys for about 10 years to identify the pheromone and its structure, and figure out how to use pheromones to control the population.

Johnson joined the team five years ago, when he was a graduate student in Li’s lab. He is now a research associate in the Department of Fisheries and Wildlife.

Tests in natural streams showed the pheromone attracted female lampreys from hundreds of meters away, luring them into traps and preventing them from mating, Johnson said.

The research earned the first Environmental Protection Agency permit to put pheromones into rivers, Johnson said.

“The EPA was pretty lenient; to apply it we just had to have documentation of what we applied and how much we applied to the stream,” Johnson said.

Research of this kind has been done with insects, but not fish.

“(Pheromones) are considered environmentally benign — they’re species-specific,” Johnson said.

“In a river twice the size of the Red Cedar River, it would take about one grain of salt’s worth to activate the trap for two to three hours.”

The research is funded partly through the Michigan Agricultural Experiment Station, which helps pay Li’s salary. Li is the only one of the team that receives payment from the station, said Jamie DePolo, the station’s spokesperson.

The Great Lakes Fishery Commission and the National Science Foundation also are funding the research.

The next step in the research is to apply the pheromone to 20 streams across the Great Lakes Basin in the U.S. and Canada, to see if its use will result in a higher catch of lampreys, Johnson said.