Direct behavioral evidence that unique bile acids released by larval sea lamprey (Petromyzon marinus) function as a migratory pheromone

Abstract

Four behavioral experiments conducted in both the laboratory and the field provide evidence that adult sea lamprey (Petromyzon marinus) select spawning rivers based on the odor of larvae that they contain and that bile acids released by the larvae are part of this pheromonal odor. First, when tested in a recirculating maze, migratory adult lamprey spent more time in water scented with larvae. However, when fully mature, adults lost their responsiveness to larvae and preferred instead the odor of mature individuals. Second, when tested in a flowing stream, migratory adults swam upstream more actively when the water was scented with larvae. Third, when migratory adults were tested in a laboratory maze containing still water, they exhibited enhanced swimming activity in the presence of a 0.1 nM concentration of the two unique bile acids released by larvae and detected by adult lamprey. Fourth, when adults were exposed to this bile acid mixture within flowing waters, they actively swam into it. Taken together, these data suggest that adult lamprey use a bile acid based larval pheromone to help them locate spawning rivers and that responsiveness to this cue is influenced by current flow, maturity, and time of day. Although the precise identity and function of the larval pheromone remain to be fully elucidated, we believe that this cue will ultimately prove useful as an attractant in sea lamprey control.

Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe

“…Mechanistic factors driving these movements are still unknown, although adults locate spawning streams using a three-phase odor-mediated strategy that includes searching a shoreline while casting vertically, followed by stream-water-induced turning toward a stream mouth, where they ascend using rheotaxis (Vrieze et al 2011;Meckley et al 2014). In the Great Lakes, adult sea lampreys are highly selective in the choice of spawning streams (Morman et al 1980), and choose streams with high larval density (Moore and Schleen 1980), signaled by bile acid-based pheromones released by larvae (Bjerselius et al 2000). Lack of homing is also evident from genetic studies of spawning migrants returning from the Atlantic Ocean (Bryan et al 2005;Waldman et al 2008).…”

Capture and collection of lampreys: the state of the science

“…Timing of the adult lamprey spawning migration is dictated by a variety of environmental cues: temperature, discharge, photoperiod, and presence of olfactory cues (Hardisty and Potter 1971b;Bjerselius et al 2000;Moser et al 2005). The temporal variability in these environmental cues will dictate adult lamprey sampling intervals.…”

Mitochondrial DNA fails to reveal genetic structure in sea-lampreys along European shores

“…/j.ympev.2007 rivers and by pheromones secreted by amocoetes (e.g. Bjerselius et al, 2000) which means that after a local extinction the re-colonization of a river may be difficult.…”