Development of Rations for the Enhanced Survival of Salmon, 1983-1984 Progress (Annual) Report.

Hydroelectric development coupled with numerous other encroachments on the supply and quality of water has reduced the natural habitat for the spawning and rearing of salmon in the Columbia river system. Artificial production in hatcheries has become a critical link in the restoration of natural stocks of salmon. Released hatchery salmon must survive predation, be able to acquire sustainable nutrients under natural conditions, possess the vitality to surmount man-made impediments to seaward migration and adapt to a sea water environment. Survival of hatchery salmonids is dependent upon a number of factors. Time of release, natural food abundance, fish size and the health and/or quality of smolts all play synergistic roles. The nutritional and physical characteristics of ration regimes for hatchery fish plays a major role in determining the effectiveness of hatchery production and the health and/or quality of smolts.Ration regimes containing high quality components in uniform and fine-free pellet forms produce efficient growth response and minimize loss of nutrients maintaining the quality of hatchery water supply. Under such feed regimes, fish are less susceptible to disease and more uniform and desirable fish sizes can be achieved at release time. High quality smolts would help to optimize out-migration survival and successful adaptation to salt water