ABSTRACT
Quantitative genetic variation of development rate was evident among 20 half-sib and 40 full-sib families within each of two seasonally separate components of a population of pink salmon (Oncorhynchus gorbuscha) (Ho: no sire effect on temperature units at hatch, P<0.02). Differences between averages of families spawned 3 weeks apart may have had genetic or environmental sources (e.g., in constant 8 C, early embryos hatched at 606 temperature units, and late embryos, at 625). Statistical interactions between paternal effects and environmental (embryos were cultured in four temperature regimes, two simulated natural regimes and two constant temperatures; Ho: no sire by regime interaction effect on temperature units at hatch P<0.09) were weak evidence that genotype by environment interactions contributed to variation. Paternal effects in analysis of variance (evidence of additive genetic variation) were detected only at later stages. Evidences of genetic variation and of interactions between genotypes and environments are pertinent to resource conservation because they suggest that harvest management or hatchery practice have the potential to reduce genetic variation in salmon populations.
QUOTES:
Genetic variation of development rate means development rate is susceptible to selection. Evolutionary implications of variation of this life-history trait. Should be considered in management and culture of salmon; aquaculture managers and fisheries managers cannot ignore the genetic substructure observed in salmon populations. Careful managers must consider genetic structure and its effect on salmon life-history traits, such as embryonic rate of development, or else risk losing genetic variation. Losses of genetic variation would reduce not only the evolutionary fitness but also the harvestable productivity of populations.