Fig. 1. Effects of temperature acclimation on mRNA levels of (A) citrate synthase and (B) cytochrome c oxidase subunit 2 in white muscle of G. morhua from North Sea (NSC) and Barents Sea (NEAC). The relative quantities of CISY and COX2 were determined from ribonuclease protection assays. Data were corrected for loading differences using the 18S rRNA signal. Values are means ± s.e.m. (N=5–6) and expressed relative to the warm-acclimated control group (NSC, 10°C), which was set to 1. The data were tested for outliers at the 95% significance level using Nalimov's test (Noack, 1980). *Significant difference from the warm-acclimated control group within a population; *significant difference between populations at the same acclimation temperature.