The harp seal, Pagophilus groenlandicus (Erxleben 1777). XXIII. Spectral sensitivity

1972 ◽  
Vol 50 (9) ◽  
pp. 1197-1206 ◽  
Author(s):  
D. M. Lavigne ◽  
K. Ronald
Keyword(s):  
Spectral Sensitivity ◽  
Dark Adaptation ◽  
Relative Sensitivity ◽  
Visual Sensitivity ◽  
Harp Seal ◽  
Scotopic Sensitivity ◽  
Underwater Environment ◽  
Pagophilus Groenlandicus ◽  
Increased Sensitivity ◽  
Purkinje Shift

Behavioral determinations of harp seal spectral sensitivity, under light- and dark-adapted conditions, indicated the presence of a Purkinje shift. Maximum photopic sensitivity occurred near 550 nm. Scotopic sensitivity peaked in the region of 500–525 nm. A large increase in relative sensitivity, approaching 8 log units at 525 nm, accompanied dark adaptation. This confirms anatomical suggestions that the harp seal possesses excellent visual sensitivity. Increased sensitivity to green wavelengths may indicate adaptation to a particular underwater environment.

scholarly journals IODOPSIN

1955 ◽  
Vol 38 (5) ◽  
pp. 623-681 ◽  
Author(s):  
George Wald ◽  
Paul K. Brown ◽  
Patricia H. Smith
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Dark Adaptation ◽  
Visual Sensitivity ◽  
High Threshold ◽  
Scotopic Sensitivity ◽  
Rods And Cones ◽  
Near Ultraviolet ◽  
Spontaneous Reaction ◽  
Cis Isomer

The iodopsin system found in the cones of the chicken retina is identical with the rhodopsin system in its carotenoids. It differs only in the protein—the opsin —with which carotenoid combines. The cone protein may be called photopsin to distinguish it from the scotopsins of the rods. Iodopsin bleaches in the light to a mixture of photopsin and all-trans retinene. The latter is reduced by alcohol dehydrogenase and cozymase to all-trans vitamin A1. Iodopsin is resynthesized from photopsin and a cis isomer of vitamin A, neovitamin Ab or the corresponding neoretinene b, the same isomer that forms rhodopsin. The synthesis of iodopsin from photopsin and neoretinene b is a spontaneous reaction. A second cis retinene, isoretinene a, forms iso-iodopsin (λmax 510 mµ). The bleaching of iodopsin in moderate light is a first-order reaction (Bliss). The synthesis of iodopsin from neoretinene b and opsin is second-order, like that of rhodopsin, but is very much more rapid. At 10°C. the velocity constant for iodopsin synthesis is 527 times that for rhodopsin synthesis. Whereas rhodopsin is reasonably stable in solution from pH 4–9, iodopsin is stable only at pH 5–7, and decays rapidly at more acid or alkaline reactions. The sulfhydryl poison, p-chloromercuribenzoate, blocks the synthesis of iodopsin, as of rhodopsin. It also bleaches iodopsin in concentrations which do not attack rhodopsin. Hydroxylamine also bleaches iodopsin, yet does not poison its synthesis. Hydroxylamine acts by competing with the opsins for retinene. It competes successfully with chicken, cattle, or frog scotopsin, and hence blocks rhodopsin synthesis; but it is less efficient than photopsin in trapping retinene, and hence does not block iodopsin synthesis. Though iodopsin has not yet been prepared in pure form, its absorption spectrum has been computed by two independent procedures. This exhibits an α-band with λmax 562 mµ, a minimum at about 435 mµ, and a small ß-band in the near ultraviolet at about 370 mµ. The low concentration of iodopsin in the cones explains to a first approximation their high threshold, and hence their status as organs of daylight vision. The relatively rapid synthesis of iodopsin compared with rhodopsin parallels the relatively rapid dark adaptation of cones compared with rods. A theoretical relation is derived which links the logarithm of the visual sensitivity with the concentration of visual pigment in the rods and cones. Plotted in these terms, the course of rod and cone dark adaptation resembles closely the synthesis of rhodopsin and iodopsin in solution. The spectral sensitivities of rod and cone vision, and hence the Purkinje phenomenon, have their source in the absorption spectra of rhodopsin and iodopsin. In the chicken, for which only rough spectral sensitivity measurements are available, this relation can be demonstrated only approximately. In the pigeon the scotopic sensitivity matches the spectrum of rhodopsin; but the photopic sensitivity is displaced toward the red, largely or wholly through the filtering action of the colored oil globules in the pigeon cones. In cats, guinea pigs, snakes, and frogs, in which no such colored ocular structures intervene, the scotopic and photopic sensitivities match quantitatively the absorption spectra of rhodopsin and iodopsin. In man the scotopic sensitivity matches the absorption spectrum of rhodopsin; but the photopic sensitivity, when not distorted by the yellow pigmentations of the lens and macula lutea, lies at shorter wave lengths than iodopsin. This discrepancy is expected, for the human photopic sensitivity represents a composite of at least three classes of cone concerned with color vision.

The harp seal, Pagophilus groenlandicus (Erxleben, 1777). III. The underwater audiogram

1972 ◽  
Vol 50 (5) ◽  
pp. 565-569 ◽  
Author(s):  
J. M. Terhune ◽  
K. Ronald
Keyword(s):  
Ambient Noise ◽  
Free Field ◽  
Phoca Vitulina ◽  
Harp Seal ◽  
Pagophilus Groenlandicus ◽  
Increased Sensitivity

A free-field underwater audiogram from 0.76 to 100 kHz was obtained for Pagophilus groenlandicus. Areas of increased sensitivity occurred at 2 and 22.9 kHz. The lowest threshold was −32.9 db/μbar at 15.0 kHz. Above 64 kHz the threshold increases at a rate of 40 db/octave. The audiogram was similar to that of the Phoca vitulina. The effects of ambient noise on the audiogram are discussed.

Electroretinal Demonstration of a Purkinje Shift in the Chicken Eye

1956 ◽  
Vol 186 (2) ◽  
pp. 258-262 ◽  
Author(s):  
John C. Armington ◽  
Frederick C. Thiede
Keyword(s):  
Absorption Spectrum ◽  
Spectral Sensitivity ◽  
Small Contribution ◽  
Sensitivity Curve ◽  
Experimental Animals ◽  
Scotopic Sensitivity ◽  
Mixed Response ◽  
Purkinje Shift ◽  
Photopic Erg

Spectral sensitivity of the chicken electroretinogram was determined for the photopic and scotopic condition. Physiological procedures were adopted which permitted the examination of the same three experimental animals upon repeated experimental occasions. It was found that this ERG exhibits components which are typical of the eyes of other animals, and a Purkinje shift could be demonstrated. Photopic ERG sensitivity agreed with the absorption spectrum of iodopsin. The form of the scotopic sensitivity curve suggested a mixed response in which the visual purple of the rods dominated, but in which a small contribution was made by the photopic iodopsin system.

The harp seal, Pagophilus groenlandicus (Erxleben, 1777). VI. Structure of retina

1970 ◽  
Vol 48 (2) ◽  
pp. 367-370 ◽  
Author(s):  
A. R. Nagy ◽  
K. Ronald
Keyword(s):  
Ganglion Cells ◽  
Outer Nuclear Layer ◽  
Horizontal Cell ◽  
Single Layer ◽  
Amacrine Cells ◽  
Visual Sensitivity ◽  
Harp Seal ◽  
Pagophilus Groenlandicus ◽  
Area Centralis ◽  
Cell Processes

The retina of the harp seal (Pagophilus groenlandicus) was studied by means of the light microscope. Ganglion cells occupy a single layer. Thinly dispersed throughout this layer are giant ganglion cells. There is no area centralis. The inner nuclear layer consists of large horizontal cell processes with bipolar and amacrine cells between the horizontal cell processes. The outer nuclear layer is the thickest of all retinal layers. Its density is constant in the central and peripheral areas of the retina, similar to that found in the inner nuclear and ganglion layers. Only rod photoreceptors were found; therefore it is presumed that seals have no color vision. The tapetum covers an extensive area and is 32–34 cellular layers thick centrally, diminishing in thickness peripherally. The combination of tapetum and rod receptors makes possible excellent visual sensitivity to dim light.

Changes in fatty acid composition of plasma of the harp seal Pagophilus groenlandicus during the post-weaning fast

1981 ◽  
Vol 70 (4) ◽  
pp. 795-798
Author(s):  
Bruce A. Bailey ◽  
R.G.H. Downer ◽  
D.M. Lavigne ◽  
G. Drolet ◽  
G.A.J. Worthy
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Harp Seal ◽  
Pagophilus Groenlandicus

scholarly journals Estimation of harp seal (Pagophilus groenlandicus) pup production in the North Atlantic completed: results from surveys in the Greenland Sea in 2002

2006 ◽  
Vol 63 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Tore Haug ◽  
Garry B. Stenson ◽  
Peter J. Corkeron ◽  
Kjell T. Nilssen
Keyword(s):  
North Atlantic ◽  
Barents Sea ◽  
Temporal Distribution ◽  
Harp Seal ◽  
Greenland Sea ◽  
The North ◽  
Pagophilus Groenlandicus ◽  
Pack Ice ◽  
Photographic Survey ◽  
Strip Transect

Abstract From 14 March to 6 April 2002 aerial surveys were carried out in the Greenland Sea pack ice (referred to as the “West Ice”), to assess the pup production of the Greenland Sea population of harp seals, Pagophilus groenlandicus. One fixed-wing twin-engined aircraft was used for reconnaissance flights and photographic strip transect surveys of the whelping patches once they had been located and identified. A helicopter assisted in the reconnaissance flights, and was used subsequently to fly visual strip transect surveys over the whelping patches. The helicopter was also used to collect data for estimating the distribution of births over time. Three harp seal breeding patches (A, B, and C) were located and surveyed either visually or photographically. Results from the staging flights suggest that the majority of harp seal females in the Greenland Sea whelped between 16 and 21 March. The calculated temporal distribution of births were used to correct the estimates obtained for Patch B. No correction was considered necessary for Patch A. No staging was performed in Patch C; the estimate obtained for this patch may, therefore, be slightly negatively biased. The total estimate of pup production, including the visual survey of Patch A, both visual and photographic surveys of Patch B, and photographic survey of Patch C, was 98 500 (s.e. = 16 800), giving a coefficient of variation of 17.9% for the survey. Adding the obtained Greenland Sea pup production estimate to recent estimates obtained using similar methods in the Northwest Atlantic (in 1999) and in the Barents Sea/White Sea (in 2002), it appears that the entire North Atlantic harp seal pup production, as determined at the turn of the century, is at least 1.4 million animals per year.

Performance of Genetically-Colorblind Individuals on a Rapid Dark Adaptation Test Based on the Purkinje Shift

1983 ◽  
Vol 56 (1) ◽  
pp. 251-258
Author(s):  
Vivian Kim ◽  
Noel W. Solomons
Keyword(s):  
Dark Adaptation ◽  
Light Energy ◽  
Retinal Sensitivity ◽  
Adaptation Test ◽  
Purkinje Shift

An experiment was conducted to determine whether or not genetic colorblindness would limit performance on a rapid dark adaptation test (RDAT) which is based on the Purkinje shift in retinal sensitivity to lower wavelengths of light energy under mesopic/scotopic conditions of illumination. No differences in RDAT performance between age-equivalent colorblind and non-colorblind subjects was observed.

Calling depth and time and frequency attributes of harp (Pagophilus groenlandicus) and Weddell (Leptonychotes weddellii) seal underwater vocalizations

2005 ◽  
Vol 83 (11) ◽  
pp. 1438-1452 ◽  
Author(s):  
Hilary B Moors ◽  
John M Terhune
Keyword(s):  
Light Condition ◽  
Weddell Seal ◽  
Harp Seal ◽  
Vertical Array ◽  
Vocal Cords ◽  
Leptonychotes Weddellii ◽  
Call Duration ◽  
Weddell Seals ◽  
Pagophilus Groenlandicus ◽  
Breeding Seasons

Harp seal (Pagophilus groenlandicus (Erxleben, 1777)) daytime calling depth during the breeding season and Weddell seal (Leptonychotes weddellii (Lesson, 1826)) daytime and nighttime calling depth during the winter and breeding seasons were investigated using a small vertical array with hydrophones placed at depths of 10 and 60 m. Rough calling depth estimates (<35 m, ~35 m, >35 m) and more accurate point depth estimates (±5–10 m in most cases) were obtained. Significantly more calls were produced at depths ≤35 m for both species. The point depth estimates indicated that the calls occurred most frequently at depths >10 m; 60% of harp seal calls and 71% of Weddell seal calls occurred at depths between 10 and 35 m. The seals called predominately within areas of the water column where light would likely penetrate, but still avoided sea-ice interference to some extent. The vocalizations did not change over depth with respect to call type, the number of elements within a call, or total call duration, or with respect to season and light condition for Weddell seals. Frequency (kHz) of calls also did not change with depth, suggesting that harp and Weddell seals control the pitch of their vocalizations with the vocal cords of the larynx.

Preliminary Underwater Observations of the Breeding Behavior of the Harp Seal (Pagophilus groenlandicus)

1978 ◽  
Vol 59 (1) ◽  
pp. 181-185 ◽  
Author(s):  
B. R. Merdsoy ◽  
W. R. Curtsinger ◽  
D. Renouf
Keyword(s):  
Harp Seal ◽  
Breeding Behavior ◽  
Pagophilus Groenlandicus

Functional Hematology of the Harp Seal Pagophilus groenlandicus

1971 ◽  
Vol 44 (3) ◽  
pp. 162-170 ◽  
Author(s):  
J. R. Geraci
Keyword(s):  
Harp Seal ◽  
Pagophilus Groenlandicus
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