Life history of the Lahontan cutthroat trout, Salmo clarki henshawi in Pyramid Lake, Nevada

The Pyramid Lake Lahontan cutthroat trout (S. clarki henshawi) population was sampled on a monthly basis from November 1975 through December 1977. Peak annulus formation occurs in March and April, followed by the period of maximum growth. Scale patterns illustrate a variable growing season. Maximum growth in length is in the first three years of life; after that males begin to grow faster than females. Small trout feed primarilly on zooplankton and benthic invertebrates; cutthroat trout > 300 mm are piscivorus, feeding almost exclusively on tui chub Gila bicolor) . The spawning migration of Pyramid Lake cutthroat trout to the Marble Bluff egg taking facility in spring 1976 and 1977 peaked in April and May. Females mature at three or four years and males mature at two or three years.