Salmon Smell Their Way Home The mystery of how adult salmon in their spawning migration unerringly return to the same stream in which they were hatched seems to have a chemical answer. Wisconsin zoolaeists R. M. Horrall and J. C. Caooer first exoosed voune coho concentrations. After the exposure, the salmon were released into Lake Michigan. When the salmon began their spawning migration eighteen months later, the Wisconsin scientists introduced morpholine into one potential spawning stream and phenethyl alcohol into a second stream. They found that 94.1% of the morpholinetreated fish were captured in the morpholine-scented stream and 90.5% of the phenethyl alcohol-treated fish were captured in the alcohol-scented stream. This study suggests that coho salmon use familiar odors to guide them back to the stream where they were hatched.
Volume 55. Number 1, January 1978 1 11
