Researchers at East Lansing’s Michigan State University, Kalamazoo’s Western Michigan University, and the University of Minnesota have discovered a fatty molecule that directs sea lamprey migration. The discovery could lead to better ways to control the destructive animals.
Sea lampreys are an invasive species that infiltrated the upper Great Lakes from the Atlantic Ocean in the 1920s through shipping canals. They feed by attaching themselves to other fish, such as salmon and trout, and a single sea lamprey can kill more than 40 pounds of fish. The U.S. and Canadian governments spend about $20 million annually to control them in the Great Lakes.
“We’ve found a pheromone, a fatty acid derivative, that’s released by larval sea lamprey and guides migratory adults to spawning grounds,” says Weiming Li, MSU professor of fisheries and wildlife and co-lead author of the study. “Because the pheromone bridges two distinct life stages and transmits through two different habitats, it holds a potential to disrupt adult sea lamprey as they try to reproduce.”
Scientists have suspected for decades that such an odorant exists but could not identify it.
The team of scientists relied on the collection of tens of thousands of larval sea lampreys by the U.S. Fish and Wildlife Service, Fisheries and Ocean Canada, and U.S. Geological Survey. They extracted the pheromones for identification and tested them in streams.
The newly identified pheromone guides migratory adults to swim upstream to spawning grounds. Once on the spawning ground, the males release a scent to attract females. The molecule synthesized was potently stimulatory for the nose of the adults, and, at less than 0.1 parts per trillion, induced preference of migratory adults in stream selection.
“The potential for application in sea lamprey control is quite good, though we still have some work to do,” says Li. “For instance, as we do not yet know how well we can use this pheromone to outcompete or disrupt all the other signals sea lamprey uses to spawn.”
The results of the study were published in the current issue of Proceedings of the National Academy of Sciences of the United States of America. The research is funded in part by the Great Lakes Fishery Commission, National Science Foundation, and MSU AgBioResearch.