This was done in the 60's on the mid-columbia for steelhead and I believe salmon also. It was before my time, but I remember the "old timers" talking about the study over several years on the adult upstream migration and year after year, the mass majority of steelhead followed the same patterns. They would change which side of the Columbia they were miswimming on at the same places and they would "sniff" the same creeks (but not all creeks!). Cool stuff!!!