Abstract
The spectral composition and intensity of light penetrating different parts of fresh preparations of the upper part of the skull of Atlantic salmon (Salmo salar) (fork length 25–30 cm) was investigated. All measurements were made in an aqueous medium, by moving the tip of an optical fibre in a three dimensional lattice below preparations that were illuminated by a parallel light source from above. The intensity of the transmitted light showed a well-defined maximum just below the pineal groove. Light that penetrated the skull from a source vertically above was refracted to produce a focusing point in the approximate position of the pineal body. Light projected from angles of 45° relative to the vertical position was only slightly (25%) attenuated, thus indicating a wide acceptance angle.
There was an almost uniform transmission of light (of 3%) between 500 and 700 nm. The transmittance of UV light (350 nm) was about 10% of that of green light. These differences are small when compared with the intensity range reported for the pineal light receptors. The transmission properties are discussed in relation to the known diurnal changes in the spectral composition of natural light.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References cited
Davies, P.R., Hanyu, I., Furukawa, K. and Nomura, M. 1986. Effect of temperature and photoperiod on sexual maturation and spawning of the common carp III. Induction of spawning by manipulating photoperiod and temperature. Aquaculture 52: 137–144.
de Vlaming, V.L. and Olcese, J. 1981. The pineal and reproduction in fish, amphibians, and reptiles. In The Pineal Gland. Vol. II, Reproductive effects. pp. 1–29. Edited by R.J. Reiter. CRC Press Inc., Boca Raton.
Dodt, E. and Heerd, E. 1962. Mode of action of pineal nerve fibers in frogs. J. Neurophysiol. 25: 405–429.
Dye, H.M., Sumpter, J.P., Fagerlund, U.H.M. and Donaldson, E.M. 1986. Changes in reproductive parameters during the spawning migration of pink salmon, Oncorhynchus gorbuscha (Walbaum). J. Fish Biol. 29: 167–176.
Ekstöm, P. and van Veen, T. 1983. Central connections of the pineal organ in the three-spined stickleback, Gasterosteus aculeateus L. (Teleostei). Cell Tiss. Res. 232: 141–155.
Ekström, P. and Korf, H.-W. 1985. Pineal neurons projecting to the brain of the rainbow trout, Salmo gairdneri Richardson (Teleostei). Cell Tiss. Res. 240: 693–700.
Falcón, J. and Meissl, H. 1981. The photosensory function of the pineal organ of the pike (Esox lucius L.). Correlation between structure and function. J. Comp. Physiol. 144: 127–137.
Gruber, S.H., Hamasaki, D.I. and Davis, B.L. 1975. Window to the epiphysis in sharks. Copeia 2: 378–380.
Hartwig, H.G. and van Veen, T. 1979. Spectral characteristics of visible radiation penetrating into the brain and stimulating extraretinal photoreceptors. J. Comp. Physiol. 130: 277–288.
Jafri, S.I.H. and Ensor, D.M. 1983. The morphology and histology of the pineal organ in roach, Rutilus rutilus (L.). J. Fish Biol. 23: 251–256.
Hanyu, I., Niwa, H. and Tamura, T. 1978. Salient features in photosensory function of teleostean pineal organ. Comp. Biochem. Physiol. 61A: 49–54.
Korf, H.-W., Liesner, R., Meissl, H. and Kirk, A. 1981. Pineal complex of the clawed toad Xenopus laevis, structure and function. Cell Tiss. Res. 216: 113–130.
Krüll, F. 1976. Zeitgebers for animals in the continuous daylight of high arctic summer. Oecologia (Berl.) 24: 149–158.
Meissl, H. and Dodt, E. 1981. Comparative physiology of pineal photoreceptor organs. In The Pineal Organ: Photobiology-Biochronometry-Endsocrinology. pp. 61–79. Edited by A. Oksche and P. Pevet. Elsevier/North-Holland Biomedical Press, Amsterdam.
Morita, Y. 1966. Entladungsmuster pinealer Neurone der Regenbogenforelle (Salmo irideus) bei Belichtung des Zwischenhirns. Pflügers Arch. ges. Physiol. 289: 155–167.
Nordtug, T. and Melø, T.B. 1988. Diurnal variations in natural light conditions at summer time in arctic and subarctic areas in relation to light detection in insects. Hol. Ecol. 11: 202–210.
Tamotsu, S. and Morita, Y. 1986. Photoreception in pineal organs of larval and adult lampreys, Lampetra japonica. J. Comp. Physiol. 159: 1–5.
Weber, L.J. and Smith, J.R. 1980. Possible role of the pineal gland in migratory behaviour of salmonids. In Salmonid Ecosystems of the North Pacific. pp. 313–320. Edited by W.J. McNeil and D.C. Himsworth. Oregon State University Press. Cornvallis.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nordtug, T., Berg, O.K. Optical properties of the pineal window of Atlantic salmon (Salmo salar L.). Fish Physiol Biochem 8, 541–546 (1990). https://doi.org/10.1007/BF00003412
Issue Date:
DOI: https://doi.org/10.1007/BF00003412