The scotopic photoreceptors and their visual pigments of fishes: functions and adaptations

I have been impressed, by the spectral diversity of vertebrate vision, a diversity that does not appear to be a matter of random variation but, instead, of a systematic evolutionary response in adaptation to the habits and habitats of the species. Fishes, inhabitants of marine and freshwater environments of varying and changeable optical character, perhaps best illustrate the biological significance of this diversity. For this meeting I have selected a number of examples from the literature, and from studies of my laboratory, that bring out the evolutionary versatility of fishes in adjusting scotopic vision to the aquatic ecology.