Growth, biomass, and production of juvenile Atlantic salmon (Salmo salar L.) in two Miramichi River, New Brunswick, tributary streams

The production rate of juvenile Atlantic salmon (Salmo salar) was estimated at four sites in two tributary streams of the Miramichi River, New Brunswick, during the period September 1976 to October 1978. Annual production ranged between 0.27 and 5.12 g∙m−2∙year−1. Growth was largely restricted to a 4-month period in early summer. Among the four sites, age 0+ salmon attained a mean weight of between 0.95 and 3.50 g by the end of their first growing season (September) and densities in July ranged between 0.3 and 3.1 fry∙m−2∙Age 1+ parr grew to mean weights between 4.95 and 12.45 g by September, and June–July densities ranged between 0.03 and 0.6 parr∙m−2. Marking information indicated that most parr remained in the study sites from July to September, but larger proportions of migrant parr were recorded in October. Production during summer was directly and positively related to initial population densities. Production rates at these sites were lower than most other recorded values for juvenile Atlantic salmon. Biomass of salmon may have been below the carrying capacity of the environment at all four sites.