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BUIvI/ETIN of the bureau of fisheries 
4. Dog salmon mature normally either in their third, fourth, or fifth years, the 
humpback always in their second year. The young of both species pass to sea as soon 
as they are free swimming. 
5. The term “grilse,” as used for Pacific salmon, signifies conspicuously undersized 
fish which sparingly accompany the spawning run. They are precociously developed in 
advance of the normal spawning period of the species. So far as known, the grilse of 
the king salmon, coho, and dog salmon are exclusively males, of the sockeye, almost 
exclusively males, except on the Columbia River, where both sexes are about equally 
represented. The larger grilse meet or overlap in size the smaller of those individuals 
which mature one year later at the normal period. 
6. Grilse of the sockeye are in their third year, of the king salmon in their second or 
third year, of the coho and the dog salmon in their second year. 
7. The great differences in size among individuals of a species observed in the 
spawning run are closely correlated with age, the younger fish averaging constantly 
smaller than those one year older, though the curves of the two may overlap. 
