If it is assumed that rates of exploitation, regardless of where fishing takes place, can be adjusted to the needs for reproduction, maximum yield from stocks of north Pacific sockeye salmon (Oncorhynchus nerka) will then be a function of growth and natural mortality rates. Events during the last decade have demonstrated the vulnerability of this species to pelagic fishing during the penultimate and ultimate years of life. The instantaneous growth rate on a per-month basis (g) is estimated from diverse data by back calculation, tag and recapture, and size-at-time methods. A general consistency of results is apparent regardless of the method utilized. For 2-ocean annuli life history types, penultimate [Formula: see text], ultimate [Formula: see text]. For 3-ocean annuli types, penultimate g = 0.059, ultimate [Formula: see text]. Ocean mortality models and rates derived by several researchers are reviewed and discussed. Using those proposed by the author, it is shown that the stock mass, hence the allowable yield, increases throughout the penultimate and ultimate years in the sea and reaches a maximum when the stocks approach the coast on the spawning migration. A conservative estimate of the potential increment, based on the 1957–1959 pelagic catches, is 14.2%. It is concluded that the yield of these stocks is seriously depressed by pelagic fishing.