Possible applications of pheromones in an integrated sea lamprey management program

A group of research scientists and fishery managers met during the Sea Lamprey International Symposium II to discuss how recent progress understanding sea lamprey (Petromyzon marinus) pheromone systems might contribute to an integrated management program. Summarized here are those discussions about how pheromone cues might be used and what steps should be taken to develop them as new tools in Great Lakes sea lamprey management. It is now evident that larval sea lampreys release a migratory pheromone that guides maturing adults into streams, and that mature sea lampreys use sex pheromones to affect locomotion and distribution of conspeciftc individuals on spawning grounds. Synthetic and purified pheromones have potential to enhance trap efficiencies, divert spawning migrations to streams with favorable management characteristics, and disrupt spawning behavior. Populations of native lamprey species might be established in strategic locations to provide migratory pheromone attraction. Pheromone production in spawning-phase males could be enhanced to bait traps and lure females, or to provide sterilized males with a competitive advantage in mating. Assays for analysis of the migratory pheromone could estimate the size of spawning runs and detect larval populations in streams. Pheromone strategies that integrate and enhance existing management techniques are likely to be the most beneficial. For example, the low density of adult sea lampreys in the St. Marys River makes it a good candidate for use of pheromones to enhance the current strategy of sterile-male release and trapping. Variation in recruitment and changes in growth and mortality could affect success of pheromone strategies that reduce reproduction. Continued support for basic research into developing and understanding pheromones and the new technologies associated with them is recommended.