Table 2. Occurrence of major life history traits in native Pacific salmon populations from North America. Symbols represent proportion of populations that predominantly express the indicated trait: +++ majority; ++ approximately half; + minority; - trait is absent in the species; * a minority of individuals in some populations express the trait. Modified from Waples et al. (2001).


Species Age at smolting Winters at sea Anadromous Spawning
<1 1 >1 <1 1 >1 Yes No Semelparous Iteroparous
Pink All - - - All - All - All -
Chum All - - - - All All - All -
Sockeye + + +++ - + +++ +++ + All -
Coho * +++ +a *b All * All - All -
Chinook ++ ++a * *b + +++ All * All -
Steelhead - + +++ * ++ ++ ++ ++ +++c +

aSmolt age in these species is generally older in populations from central B.C. to the north.
bOnly males express this trait.
cIn most pure steelhead populations, the fraction of individuals that spawns more than once is small.