Do Native Pacific Lamprey and Invasive Sea Lamprey Share an Alarm Cue? Implications for Use of a Natural Repellent to Guide Imperiled Pacific Lamprey into Fishways

Instream barriers affect anadromous lampreys worldwide by preventing access to spawning habitat, resulting in the decline of several species. Because lampreys rely heavily on olfactory cues to choose movement paths during upstream migration in rivers, the manipulation of these cues may be used to guide individuals into the vicinity of fish passage devices and thereby mitigate the impacts of barriers during migration. However, because experimentation with imperiled species presents significant legal and ethical challenges, use of a surrogate species that exhibits similar responses may prove very useful. Our laboratory study established that (1) the odor derived from dead Pacific Lamprey Entosphenus tridentatus elicits an avoidance response from invasive Sea Lamprey Petromyzon marinus from the Laurentian Great Lakes, and (2) the magnitude of this response does not differ from the conspecific alarm cue present in Sea Lamprey. By presenting the odor on the side of a river channel opposite a lamprey fish passage device, migrating lampreys of conservation concern may be guided to fishways, if the behavioral response to the cue has evolved in these taxa. Due to their availability and well‐studied chemical communication system, Sea Lamprey may prove to be a useful surrogate for identifying and producing chemosensory cues for use in guiding Pacific Lampreys towards fish passage devices and away from intakes and screens. Received December 10, 2015; accepted May 6, 2016 Published online August 31, 2016