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Excerpt from Age at Maturity of the Pacific Coast Salmon of the Genus Oncorhynchus
Three-year fish, or grilse, were not included in the above table. During the summer of 1911 they were not numerous. Only a few (perhaps three or four on the average) could usually be found in each fish brought in. It is the current belief among those who handle Fraser River sockeyes that all the grilse are male fish. As previously noted, all those examined by us were males, with one exception, a female with well-developed ova. Examina tion of the scales (see Pl. 1, Fig. 2) shows that the final summer's growth is more extensi1e in grilse than in those which mature at four and five years, and the narrowing of the marginal rings to form the third winter band has often begun.
Much larger specimens than those included in the table were selected for examination in an attempt to find individuals older than five years. Several were found over 30 inches long. Weighing 12 lb. But all were five-year fish. Examination of a larger number may possibly bring to light's rare individual which has not matured until its sixth year. Even this is doubtful, and we assuredly do not anticipate finding older than six year individuals among the Fraser River sockeyes. 'lhe significance of the marking experiments of the Bureau of Fisheries in the Naha River, with the reported recovery of marked specimens up to nine years old, remains to be determined.
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