Figure 4.
The estimated fitness of Snake River fall Chinook salmon that adopt the yearling tactic relative to those that adopt the subyearling tactic as a function of the smolt survival of yearlings relative to that of subyearlings, at three levels of yearling smolt overwinter survival probability (Sriver). Three relative-fitness functions are presented in each panel, one for individuals maturing at ages 3–5 years. In each case, the fitness function for individuals maturing at age 5 has the highest elevation whereas that for individuals maturing at age 3 has the lowest elevation.