They have been doing the acoustic tags since about the turn of the century. They have identified places where mortality occurs (HC Bridge) and identifies losses but what is totally lacking is a historical perspective. For example, on the stream I worked on we marked 100% of the smolts (steelhead, coho, CT) and actually measured survival to adult return. For steelhead, marking 100% of the smolts from about 85% of the anadromous zone resulted in about 1/3 of the returning adults being marked.

It is my belief, based on all the data sets I can find, that it is very rare for steelhead to have an R/S of 1, when measured to first return. We have to have the repeats. Also, the data from WA and BC says that R/S increases as smolt age decreases (more nutrients). The couple streams I have calculated where R/S=1 is mean smolt age of 1.5.

There is a lot going on in the marine waters. Certainly predation is taking a big chunk. There is also a lot off correlations which suggest a paucity of food, at least in the areas frequented by the Pacific Salmon.