Publication Abstract

We conclude that spermiating male sea lamprey release a large amount of 7&agr;,12&agr;,24-trihydroxy-5&agr;-cholan-3-one 24-sulfate via their gills. We suggest that this compound is used to signal the location of their nests to ovulated females downstream. The role of the minor component, 3kACA, has yet to be determined. The selection pressure to signal over a long distance in rapid flowing water may have favored the evolution of a bile acid derivative (as opposed to a gonadal steroid) as a pheromone. Considering the size of the liver, bile acids can be produced in relatively large quantities. Interference with this pheromone system offers an attractive target for selective and environmentally benign control of the sea lamprey.