A New Mating Pheromone Component of the Sea Lamprey: Quest for the Ultimate Trapping Cocktail

The sea lamprey (Petromyzon marinus L.), a non-native invader of the Laurentian Great Lakes, has evolved a dependency upon mating pheromones to synchronize their reproductive events. The potent odors are released by mature males, and serve as a cue to ovulated females that the male sender is ready for courtship. In this study, we identified a new sulphate-conjugated bile alcohol, 3,12-diketo-4,6-petromyzonene-24-sulfate (DKPES) using stream bioassay-guided fractionation from water that contained sexually mature male sea lamprey. Side-by side stream nests baited with a mixture of DKPES and 3-keto petromyzonol sulphate, (3KPZS; the main component of the male sea lamprey mating pheromone; ratio 1:30, v:v), attracted equal numbers of females compared to the adjacent nest baited with 3KPZS alone. When DKPES:3KPZS mixtures were applied at ratios of 2:30 and 10:30, the proportion of females that entered baited nests increased to 73% and 70%, respectively. DKPES, alone, did not influence preference behavior. The results of this study indicate that DKPES is a component of the sea lamprey sex pheromone, and is the second biologically active compound identified from this pheromone. DKPES holds considerable promise for increasing the effectiveness of pheromone-baited trapping as a means of sea lamprey control in the Laurentian Great Lakes.