Fig. 6From: The consistent difference in red fluorescence in fishes across a 15 m depth gradient is triggered by ambient brightness, not by ambient spectrumMaximum and minimum fluorescence brightness of Tripterygion delaisi eyes. Iris fluorescence brightness measured as total photon radiance (photon s−1 sr−1 m−2), based on 20 freshly caught fish at euryspectral (−5 m) and stenospectral (−20 m) depths, 20 fish measured after the spectrum experiment, and 19 fish measured after the brightness experiment. Cross lines represent significant differences between groups with significance level indicated (*p < 0.05, **p < 0.01). Note that measurements cannot be directly compared between experiments due to non-standardized measuring conditionsBack to article page