John T. Konecki | Geology Reports

USGS1995

Critical thermal maxima of coho salmon ( Oncorhynchus kisutch ) fry under field and laboratory acclimation regimes

Juvenile coho salmon ( Oncorhynchus kisutch ) from three populations in Washington State were captured in the field and tested for critical thermal maximum (CTM). Tolerances varied among the populations (mean CTMs were 28.21, 29.13, and 29.23 °C) and exceeded published data from some laboratory tests. The population from a relatively cool stream had a lower CTM than the two populations from warmer streams. However, after the salmon had been in the laboratory for 3 months under constant, common temperature regimes, the CTMs no longer differed, indicating that the population-specific differences resulted from different acclimation regimes rather than from genetic adaptation.

Washington↗

USGS1995

Influence of temperature on incubation rates of coho salmon ( Oncorhynchus kisutch ) from ten Washington populations

Coho salmon from 10 Washington populations were incubated under controlled conditions to determine the levels of variation in time to hatch among populations and families within populations. The average incubation rate was somewhat slower than that estimated from a quantitative model derived from British Columbia populations, and was slightly faster than that predicted by a Washington model. Significant variation in incubation rated among the Washington populations was detected, consistent with results from other studies. Data of first hatching of families within populations ranged more than two weeks at 6°C. Within families, the first and last individuals to hatch ranged over 1-3 weeks. The variation within populations and families will contribute to the variation in emergence date of fry, which will affect their growth and survival.

Washington↗