Upstream migrations of anadromous Arctic charr, Salvelinus alpinus, were monitored in the Fraser River, Labrador. Samples of charr were randomly obtained from 1975 to 1979 for biological analysis of age, growth, reproductive, and migratory characteristics. The run begins in mid-July and extends until late September. Larger charr tend to enter the river first with a progressive decrease in mean length throughout the run. Size and age composition of migrant charr range from 13 to 82 cm ([Formula: see text], 45.1 ± 7.3) and from 3 to 18 years (8.3 ± 1.7), respectively. Spawning activity peaks during the last 2 weeks in October. Fecundity of fish 41–61 cm in fork length ranged from 2316 to 9245 eggs (4665 ± 434) with approximately 75% of females mature by 8 years of age. There was no evidence from tag recaptures over an 8-year period (1976–1983; N = 241) that Fraser River charr undergo extensive marine migrations. Approximately 84% of the recaptures were from fish which either returned to the Fraser River or were caught in commercial and domestic fisheries in adjacent Nain and Tikkoatokak bays. In comparison with other North American Arctic charr populations, Fraser River charr are similar with respect to the large variability observed in age at length, variable maturation cycle, and preponderance of females at sea during the summer. Differences, however, occur among individual life history characteristics such as growth rate, size and age at first seaward migration, size and age at maturity, fecundity, and movements at sea.
Environmentally Modulated Repeat Evolution of Polymorphic Arctic Charr Life History Traits
