Fig. 5. RH2 opsin subtype expression in dorsal retinas of alevin, parr and TH-treated alevin coho salmon (Oncorhynchus kisutch, Walbaum) measured using real-time quantitative RT-PCR. Expression levels are the mean of three replicates per fish (N-values above error bars represent the number of fish) and were normalized to the β-actin gene. Error bars represent 2 s.e.m.