The sea lamprey, a serpentine fish that feasts on other fishes' blood, nearly wiped out the Great Lakes' native game fish populations in the 1940s. Now, researchers have characterized the primary components of the pheromone that the lamprey relies upon to find its spawning grounds. The work could provide a potent and inexpensive bait for lamprey traps.
Sea lampreys came to the Great Lakes from the Atlantic Ocean nearly a century ago. An expensive, 50-year program of vigilance has restored some native species, such as lake trout. The Great Lakes Fishery Commission will spend $15 million in 2005 to research and deploy lamprey-control methods, such as killing the larvae and trapping the adults.