Sex Pheromone Used to Trap Invasive Lamprey

Sea lamprey prey upon native fish in the Great Lakes region (like this lake trout), and will now be targeted in traps using their own sexual pheromone against them. Wikimedia Commons

The U.S. Environmental Protection Agency will begin using a sex pheromone to help trap and kill sea lampreys in the Great Lakes region, a toothy invader that sucks the blood of and wreaks havoc upon native populations of fish. It will be the first time that government has used a sex pheromone—chemicals used by animals to attract mates—to control the population of a large animal (though such chemicals have been used on invasive insects in the past).

Sea lampreys (Petromyzon marinus) have migrated west from the Atlantic coastal region over the past century, parasitizing various fish and generally being a pest along the way. They latch onto fish with their unique mouth, which the Great Lakes Fishery Commission describes as composed of "a large oral sucking disk filled with sharp, horn-shaped teeth surrounding a razor sharp rasping tongue." Inviting!

A sea lamprey. Jose Manuel Ribeiro / REUTERS

The pheromone that the EPA plans to use to defeat the fish, named 3kPZS, is produced naturally by male lamprey, but the commission has teamed up with a private company in Michigan called Bridge Organics to produce a synthetic version. The chemical will soon be applied to baited traps in streams around the Great Lakes, where field trials have shown it can "can increase trapping efficiencies by up to 53 percent and...can capture up to two times the sea lampreys that unbaited traps," said Michigan State University professor Weiming Li in a statement. Female lamprey smell the pheromone and move toward it thinking they find males there, but instead meet their doom.

The teeth of a sea lamprey. Jose Manuel Ribeiro / REUTERS