Photoreceptors and Visual Pigments as Related to Behavioral Responses and Preferred Habitats of Perches (Perca spp.) and Pikeperches (Stizostedion spp.)

A review of the literature indicated contrasts in retinal structure and function between perches (Perca spp.) and pikeperches (Stizostedion spp.). Foremost among these were differences in size and distribution of rods, size and shape of cones, extent of retinomotor responses, possession or lack of reflecting material, and relative concentrations of melanin. The perches are primarily active by daylight, whereas the pikeperches are most active during twilight or at night. The coincidental occupancy of shoal areas by yellow perch (Perca flavescens) and walleye (Stizostedion vitreum vitreum) at twilight is related to decreasing visual acuity of the former and the approach of optimum visual performance in the latter species. On this basis the two species have a classic predator–prey relationship. Key words: histology, light, Perca sp., photopic vision, predation, retina, Stizostedion vitreum vitreum, symbiosis, tapetum lucidum