title: Temporal shifts in visual pigment absorbance in the retina of Pacific salmon.
abstract: The visual pigments and photoreceptor types in the retinas of three species of Pacific salmon (coho, chum, and chinook) were examined using microspectrophotometry and histological sections for light microscopy. All three species had four cone visual pigments with maximum absorbance in the UV (lambda(max): 357-382 nm), blue (lambda(max): 431-446 nm), green (lambda(max): 490-553 nm) and red (lambda(max): 548-607 nm) parts of the spectrum, and a rod visual pigment with lambda(max): 504-531 nm. The youngest fish (yolk-sac alevins) did not have blue visual pigment, but only UV pigment in the single cones. Older juveniles (smolts) had predominantly single cones with blue visual pigment. Coho and chinook smolts (>1 year old) switched from a vitamin A1- to a vitamin A2-dominated retina during the spring, while the retina of chum smolts and that of the younger alevin-to-parr coho did not. Adult spawners caught during the Fall had vitamin A2-dominated retinas. The central retina of all species had three types of double cones (large, medium and small). The small double cones were situated toward the ventral retina and had lower red visual pigment lambda(max) than that of medium and large double cones, which were found more dorsally. Temperature affected visual pigment lambda(max) during smoltification.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada. inigo@sfu.ca
authors.forename: Iñigo Novales
authors.initials: IN
authors.lastname: Flamarique
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D008027:Light; D015591:Microspectrophotometry; D010786:Photoreceptor Cells / Q000166:cytology*; D012160:Retina / Q000737:chemistry* / Q000166:cytology; D012168:Retinal Pigments / Q000032:analysis* / Q000145:classification / Q000528:radiation effects; D012474:Salmon / Q000502:physiology*; D012684:Sensory Thresholds; D013045:Species Specificity; D013696:Temperature
chemical_list: D012168:Retinal Pigments