GENETIC-ANALYSIS OF SIZE IN AN ANADROMOUS POPULATION OF PINK SALMON

Variation of size, particularly among males, has a significant genetic basis in pink salmon (Oncorhynchus gorbuscha) in Auke Creek, southeas t Alaska. Heritability (h(2)), based on variance components of 118 ful l sib - 59 paternal half sib families of mature fish tagged as fry wit h coded micro wires, are higher in males (h(2) length: 0.8 +/- 0.3 (me an +/- SE); h(2) weight: 0.6 +/- 0.2, based on sire effect) than in fe males (h(2) length: 0.3 +/- 0.2; h(2) weight: 0.4 +/- 0.2). Realized h eritability probably would be smaller because of environment variabili ty between brood years in factors affecting size and growth. Estimates based on regression of offspring means on fathers' values are smaller (h(2) length: 0.4 +/- 0.1 in males; 0.2 +/- 0.1 in females; h(2) weig ht: 0.0 in males and 0.1 +/- 0.1 in females). Estimates of genetic, en vironmental, and phenotypic correlations of length and weight are all >0.7 (SEs <0.1). Estimates of genetic correlation between length and d ay of migration from the sea are near 0.4 +/- 0.2; estimates of enviro nmental and phenotypic correlations between these traits are smaller ( <0.2, SEs <0.1).