WN1A -
Question #3 - early marine mortality of steelhead smolts.

No I had not read that report before. However if you are interested in such things you may wish to check out -


Moore, M. E., B. A. Berejikian, E. P. Tezak. 2010. Early marine survival and behavior of steelhead trout (Oncorhynchus mykiss) smolts through Hood Canal and the Strait of Juan de Fuca. Canadian Journal of Fisheries and Aquatic Sciences, 139(1):49-61.

I believe that there is summary on the Native Fish society's web site; if you like I probably can find a link to that summary.

Back to the questions. The Hood Canal study found a similar level of mortaltiy (50 to 60%) though in that case the mortality occured over several weeks (at a rate of 2/7%/day) as the fish move through the canal and out into the Straits.

I think it has been pretty well accepted that the smolts experience pretty high mortalities when they first hit the salt and with time and growth the mortality rates drop fairly dramatically. I have to wonder that as the smolts leave the river the many are either not very fit for survival in that environment or just unlucky. Those fish are fated to become fodder to some predator and it is just a matter of time until they do so. If they hit a high density of predators they die quickly; if not it may take a little longer.

Once the smolts get by that initial predation it seems to me that the factor the ultimately determines their over all survival is the forage availability in the open ocean though you know more about such things than I do.

Quyestion # 4 -
Yes I did read all of your post.

Tight lines
Curt