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Bouffard, Wayne R.

Natural Resources

2009

MS

Sea lamprey (Petromyzon marinus) use a pheromone produced by stream resident larvae to locate a stream in which to spawn prior to their death. The components of the pheromone have been partially identified and their effectiveness at inducing repeatable and innate behaviors has been shown repeatedly in the lab and in limited field trials in the Great Lakes. To date all field trials have been conducted in areas where there is a lack of background pheromones. To be a useful management tool, pheromones will need to be applied in areas where the signal directly competes with naturally occurring pheromone. We collected and concentrated migratory pheromone from captive larvae using a technique that is a modification of established protocols used in the Great Lakes. The concentrated pheromone was used to conduct field trials in a stream system that contained natural populations of lamprey larvae.
We elevated the concentration of the side stream to approximately three times the concentration of the main-stem in an attempt to attract migrating lamprey to a small tributary within a dendritic system. Movements of tagged sea lamprey were recorded using stationary antennas. Traps were used to collect tagged and untagged migrating lamprey in both the main stem and side tributary. Sea lamprey did not change their behavior in response to the pheromone: 99% of 250 tagged and 97% of 251 untagged sea lamprey were captured in the mainstream trap and there was no difference between treatments and controls. Average times to pass each antenna and measures of indecisive behavior did not differ between control and treatment. These results indicate that the migratory pheromone signal may only be used for long-range location of a suitable spawning stream, or other environmental stimuli are more important for directing movements within a stream system.