Lake trout reproductive behavior: influence of chemosensory cues from young-of-the-year by-products

Chemosensory cues, particularly those emanating from substrate areas occupied by previously hatched young, may play an important role in the reproductive behavior of lake trout Salvelinus namaycush. Support for this hypothesis was obtained in laboratory experiments. Adults were placed in a large circular pool with four experimental reefs. Egg membranes and feces obtained from young that had hatched earlier were placed in polyester fiber in screen envelopes and positioned on selected reefs. Females approached and males contacted ('cleaned') the treated reefs but not the untreated reefs. Of 6,858 eggs recovered, 92% were from treated reefs. Some of these eggs had been fertilized and provide the first record of volitional spawning by lake trout under artificial conditions. A second experiment was less definitive, because no spawning occurred, but visual observations and analysis of videotaped behavior sequences showed that, again, adults were attracted more to reefs treated with feces of young of the year than to untreated reefs.