title: Ontogenetic changes and environmental effects on ocular transmission in four species of coral reef fishes.
abstract: Filtration by the humors, cornea and lens limits the spectrum of light available for vision as blocking compounds prevent some wavelengths from reaching photo-sensitive cells of the retina. The visual ecology of fishes is dependent upon factors changing with size and/or habitat. We predicted that ontogeny and habitat depth would affect ocular transmission for four fishes, Mulloidichthys flavolineatus, Parupeneus multifasciatus, Acanthurus triostegas, and Naso lituratus. We measured ocular transmission in specimens from a range of sizes (juvenile-adult) and capture depths (<3-37 m), and used the wavelength (nm) where transmission was reduced 50% as our comparative measure (T(50)). We modeled lens transmission varying pigment concentrations and pathlength, and compared predicted versus measured results. P. multifasciatus, M. flavolineatus, and N. lituratus showed a significant increase in short-wavelength blocking with size. A. triostegas were constant across sizes, and showed a slight but significant effect with depth. Comparisons of predicted versus observed transmission values suggest that pigment concentrations are held constant with age for all species, but species- and family-level differences emerge. The accumulation of blocking compounds in ocular tissues is a contributing means for balancing the costs and benefits of admitting short-wavelength radiation to the retina.
authors.affiliation: Hawai'i Institute of Marine Biology, University of Hawai'i, Coconut Island, P.O. Box 1346, 96744 Kane'ohe, Hawai'i, USA. pnelson@ucsd.edu
authors.forename: P A
authors.initials: PA
authors.lastname: Nelson
authors.forename: J P
authors.initials: JP
authors.lastname: Zamzow
authors.forename: S W
authors.initials: SW
authors.lastname: Erdmann
authors.forename: G S
authors.initials: GS
authors.lastname: Losey
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D001699:Biometry; D003315:Cornea / Q000502:physiology; D004463:Ecology; D005123:Eye / Q000033:anatomy & histology; D005399:Fishes; D007908:Lens, Crystalline / Q000033:anatomy & histology / Q000502:physiology*; D008027:Light; D009799:Ocular Physiological Phenomena; D010860:Pigments, Biological / Q000502:physiology; D013045:Species Specificity; D014796:Visual Perception / Q000502:physiology*
chemical_list: D010860:Pigments, Biological