In Alaska, salmon fisheries are restricted strictly to obtain the maximum sustainable yield. But the reproduction situations of salmon resources which are the scientific basis of fishery management are not cleared with a little exception of the study for red salmon.
In this paper, the reproduction situations of pink salmon resources both in Central Alaska and Southeastern Alaska are studied separately in odd year and even year class groups, using the Ricker's formula (R=aEe-bE).
To estimate the reproduction curves for each stocks, numbers of escapements and returns are estimated from the catch statistics under the adequate assumption, for fishing rate.
Following tables and figures resulted from above estimations show that the recent decrease of catches in Central Alaska and Southeastern Alaska may have been brought about by the decrease of escapement and the fall of reproduction rate respectively.