Ribbon Seals Research Articles

GROWTH IN PINNIPEDS

This review presents summary figures of, and fits growth curves to, data on body lengths (as standard length, SL, whenever possible) of pinnipeds at ages estimated to O.I y. (1) Generalized von Bertalanffy (vB) growth curves are fitted to most data: Lx = L infinity (I - ea(x-x0)b, Lx is length at age x, x0 is the origin of the curve (here chosen a priori as time of initiation of embryonic growth), L infinity is asymptotic length, a (which is negative) determines rate of approach to the asymptote, and b influences the 'shape' of the approach. (2) No single monotonic growth equation suffices for growth in length, which is linear before birth and remains so during early life. The vB equation is only suitable to describe mean lengths of newborns, and animals one or more years old. (3) Also, for males of polygynous species, two functions are needed to account for accelerated growth at puberty. Generally a Gompertz equation is adequate for adult males of these species. (4) The fitted growth equations permit statistical comparisons of sizes and growth rates, as well as of individual variability (as growth-curve residuals), among populations and species. (5) For the following species (including different populations when available), the reliability of data is assessed and parameters of growth curves are presented (with sexes separated where significantly different): walrus, California and Steller sea lions, Antarctic, subantarctic and northern fur seals, Hawaiian monk seal, crabeater, Weddell and Leopard seals, southern and northern elephant seals, bearded, hooded, ringed, Baikal, Caspian, spotted, harbour, harp, ribbon and grey seals. (6) Some novel findings pertain to individual species as follows. Although the Pacific walrus is generally stated to be the larger subspecies, females from Hudson Bay and males from Foxe Basin, in the eastern Canadian Arctic, may be as long as those from the Bering Sea. Although female Weddell seals have been assumed to grow larger than males, there is no significant difference in growth curves fitted to the most complete data. Uniquely among populations examined, the relative variability (absolute growth curve residuals/predicted lengths) of male southern elephant seals is amplified with age. Among ringed seals from Svalbard, the eastern, western and high Canadian Arctic, and the Bering, Chukchi, Okhotsk, Barents and Baltic Seas, asymptotic sizes are larger among those that breed on land-fast ice rather than floes, and size may be more variable in more extreme Arctic environments. The Baikal seal is confirmed as the smallest species of pinniped.(ABSTRACT TRUNCATED AT 400 WORDS)

Supernumerary postcanine teeth in the kuril seal (Phoca vitulina stejnegeri), the larga seal (Phoca largha) and the ribbon seal (Phoca fasciata).

The supernumerary postcanine teeth were examined in the kuril seal (Phoca vitulina stejnegeri), the larga seal (P. largha) and the ribbon seal (P. fasciata). Supernumerary postcanine teeth were found in 6.56%, 6.03% and 11.76% of them respectively. On the other hand, 1.31% of the kuril seal, 0.86% of the larga seal and 11.76% of the ribbon seal were found to have missing teeth. So, in these three species, there is a greater percentage having supernumerary teeth than missing teeth. This is a rare situation in mammals because missing teeth are more common than supernumerary teeth in many species. As the position in which supernumerary postcanine teeth were found are commonly variable, it is thought that the cause of supernumerary postcanine teeth is due to a splitting of the tooth germ rather than atavism in the kuril seal and the larga seal. Also the positions of the supernumerary teeth in the kuril seal are different from the larga seal. This difference is presumed to stem from the differences in the foetal developmental process of the maxilla and mandible of the two species.

Separation and characterization of metallothionein in two species of seals by high performance liquid chromatography-atomic absorption spectrophotometry

1. Metallothionein (MT) was separated from the livers of two species of seals, ribbon seal ( Histriophoca fasciata) and harbour seal ( Phoca vitulina), by high performance liquid chromatography-atomic absorption spectrophotometry (HPLC-AAS). 2. Both gel permeation and anion-exchange HPLC demonstrated that MT was present as a mixture of at least two isoforms in the livers of both species of seals.

Incidental Sighting of a Ribbon Seal (<i>Phoca fasciata</i>) in the Western Beaufort Sea

On 29 August 1983, an adult ribbon seal (Phoca fasciata) was seen by one of us (EIB) resting on ice in the western Beaufort Sea (71 41 N, 152 41 W), during the course of an aerial survey. The seal did not move from the ice when over-flown at 200 m, and was positively identified by its distinctive pelage. Ribbon seals are commonly found along the ice front in the Bering Sea in winter and early spring, then disperse in late spring as the sea ice breaks up and presumably become solitary and pelagic with poorly known distribution in the summer (Wilke, 1954; Naito and Konno, 1979; Burns, 1970, 1981; Stewart and Everett, 1983). Ribbon seals are rarely seen or taken by Eskimo hunters from coastal villages north of the Bering Strait, and sightings at Wainwright and Point Barrow in the northern Chukchi Sea have been described as "most unusual" (Burns, 1981). ... The observed ribbon seal may have drifted north and east with the ice from the Chukchi Sea during the summer. To our knowledge, this report constitutes the northeasternmost record of a ribbon seal.

On testicular cooling in phocid seals

Testicular and body core (intra-thoracic) temperatures were recorded in mature male harp seals (Pagophihs groenlandicuc) just prior to the mating season. In phocid seals the testicles are outside the abdomen but protected under 7-8 cm of insulating skin and blubber. The temperature of the testicles was found to be 14°C lower than body core temperature. Inspection of the veins of the pelvic and hind-flipper reglon of a male ribbon seal (Histrrophocafaciata) revealed that the testicles of phocid seals are enveloped in venous plexuses communicating with the veins of the hind flippers. It is suggested that cooling of the paraabdominal testicles of phocid seals is attained by passage of cold blood from the hind flippers through thc extra-testicular plexuses.

Incidental Catch of a Ribbon Seal (<i>Phoca fasciata</i>) in the Central North Pacific

On 30 June 1981 a juvenile male ribbon seal ... was incidentally caught in the central North Pacific ... by the Japanese salmon fishing vessel Hokucho Maru No. 2. ... Before the crew cast the seal overboard, one of us (WTE) was able to photograph it ... recover its baculum and measure standard length (Scheffer, 1967) and blubber thickness. ... To our knowledge, the record we report here is only the fifth pelagic record of a ribbon seal and the first pelagic sighting south of the Aleutian Islands in the central North Pacific.

Nasal mites (Acari:Halarachnidae) in the spotted seal, Phoca largha Pallas, and other pinnipeds of Alaskan waters.

The nasal passages of 349 pinnipeds of seven species were examined for halarachnid mites. Each of seven Steller sea lions (Eumetopias jubatus), 75 of 99 harbor seals (Phoca vitulina), and four of 71 spotted seals (P. largha) were infected, but none of 28 walruses (Odobenus rosmarus), 43 ringed seals (Phoca hispida), 58 ribbon seals (P. fasciata), and 43 bearded seals (Erignathus barbatus) was infected. The sea lions harbored Orthohalarachne attenuata (Banks, 1910) and O. diminuata (Doetschman, 1944), and the harbor and spotted seals harbored Halarachne halichoeri Allman, 1847. The finding of H. halichoeri in the spotted seals is a new host record.

Dipetalonema spirocauda in Alaskan marine mammals.

Dipetalonema spirocauda were found in 17 of 369 (4.6%) free-living ringed seals (Phoca hispida), 4 of 47 (8.5%) spotted seals (Phoca vitulina largha), 17 of 99 (17.2%) harbor seals (Phoca vitulina richardii), 1 of 19 (5.3%) ribbon seals (Phoca fasciata), and 2 of 51 (3.9%) bearded seals (Erignathus barbatus) collected from March, 1975 through September, 1979 in Alaskan waters. This is the first report of D. spirocauda in ribbon and bearded seals. Certain species of marine mammals from the families Ursidae, Otarridae, Odobenidae, Balaenidae, Phocaenidae and Monodontidae also were examined but none was found to be infected.

Feeding of ribbon seals (Phoca fasciata) in the Bering Sea in spring

Digestive tracts of 61 ribbon seals (Phoca fasciata) collected in the seasonal pack ice of the Bering Sea during March to June 1976–1979 were examined. Very little fresh food was found in stomachs; however, hard parts of prey, particularly fish otoliths, were found in stomachs and (or) intestines of 28 seals. Based on counts of otoliths, the main prey were pollock in south-central and central Bering Sea, and arctic cod in northern Bering Sea. Weights and lengths of fishes consumed by seals were estimated from measurements of otoliths. On the basis of estimated whole weight of prey consumed, eelpout were a major food of these seals in south-central and central Bering Sea. Comparison of the species composition of fishes caught in trawls and eaten by seals suggests that seals in central and northern Bering Sea select for pollock and arctic cod, and against sculpins and capelin. In contrast, in south-central Bering Sea pollock was the most abundant fish in both seals and trawls. Seals were nonselective with regard to size of pollock consumed but appeared to select for large arctic cod. Our data suggest feeding conditions may be more favorable for ribbon seals in south-central Bering Sea than in more northern areas.

Fatty acid composition of blubber from the four species of Bering Sea phocid seals

The fatty acid composition of blubber lipid was analyzed from one example of both sexes of the four species of phocid seals inhabiting the Bering Sea: spotted seal (Phoca vitulina largha), ringed seal (P. hispida), ribbon seal (P. fasciata), and bearded seal (Erignathus barbatus). All specimens had similar fatty acid complements (10 fatty acids predominated, ranging from chain lengths of 14 to 22 carbons with zero lo six double bonds) although there were specific differences among species and between sexes. The greatest interspecific differences in blubber fatty acid composition occurred in the ringed seal and may have been due to diet.Double-bond indices (indicating degree of unsaturation) were high in all samples and higher than those calculated for Atlantic or southern hemisphere seals. Melting points of the blubber lipid ranged from −2 to −8 °C for some components; all components melted below 15 °C correlating with expected peripheral blubber temperatures of seals in cold water of the Bering Sea.

Studies on the Hemoglobins of Pinnipeds

Abstract The hemoglobins of seven species of pinnipeds-elephant, ribbon, fur, harbor, and grey seals, walrus, and California sea lion-had two major and one minor hemoglobin fractions on electrophoresis at pH 8.6. One of the major fractions in all seven species had the same electrophoretic mobility. The second fractions of the gray, harbor, and ribbon seals were similar, but different from the second fractions of the walrus, fur seal, and sea lion. The second fraction of the elephant seal was different from all the others. The proportion of the two major fractions was about 3:1 in the elephant, grey, ribbon, and harbor seals, and about 1:1 in the fur seal, walrus, and sea lion. These results correlated well with the pinniped phylogenetic chart derived by classical morphology. All hemoglobin fractions were found to be alkali sensitive and heat stable. Gel filtration studies with Sephadex G-75 and G-100 indicated that the elephant seal hemoglobins had a mol wt of about 65,000. The amino acid compositions of the chains isolated from the hemoglobin fractions suggested that in the elephant seal one major fraction had two alpha and two beta chains, and the other major fraction had four like chains. The presence of a hemoglobin which is composed of a tetramer of like chains could be functionally advantageous to deep diving mammals.

Comparative morphology of the skull of the Ribbon seal, Histriophoca fasciata, with remarks on systematics of Phocidae

Study of skulls from 145 Ribbon seals, mainly from the Bering Sea, disclosed much greater variation in form than was indicated by earlier descriptions. The characters of greatest diagnostic value in the Ribbon seal are the short rostrum, broad cranium with reduced temporal fossae. short, wide palate with small, widely spaced teeth, and the elongate, thickwalled bullae with massive, widely exposed petrosals. Comparison of these skulls with examples from each of the other recognized genera of Phocidae revealed several deficiencies in the referred cranial characteristics of taxa at all ranks below the family. Provisional support for J. E. King's recently proposed division of the Phocidae into two subfamilies, Phocinae and Monachinae, is reported; the distinctions formerly employed for diagnosis of a third subfamily, Cystophorinae, can be ascribed to convergent evolution. Craniologically, the subfamily Phocinae is divisible into three tribes: Erignathini, Cystophorini, and Phocini. The first two are monotypic; the third is polytypic. The subtribes Phocina and Histriophocina are untenable; while Histriophoca's nearest structural relative is Pagophilus, the latter shows equal or closer relationship with Phocu. Within the tribe Phocini, only the Grey seal, Hlichoerus grypus, shows sufficient cranial differentiation for recognition as a monotypic genus. The other four major taxa within that tribe show a complex system of intergrading characters that disallows generic recognition, other than as a polytypic group. Therefore, the Ribbon, Harp, Harbor, and Ringed seals are re‐assigned to subgeneric rank, under the inclusive genus Phoca (sensu luto).

Taxonomy of Harbor Seals of the Western North Pacific and Evolution of Certain Other Hair Seals

The ice-breeding harbor seal of the western North Pacific is morphologically distinct and reproductively isolated and thus deserves status as a separate species, Phoca largha Pallas. The ice-breeding harbor seal apparently evolved from the ringed seal group (Pusa) in the western North Pacific, and this ice-breeding form later gave rise to land-breeding Phoca vitulina in the eastern North Pacific, from which the latter then entered the Atlantic via the Arctic. Phoca kurilensis Inukai (= P. insularis Belkin) differs from P. largha morphologically and behaviorally and may represent a separate local development of land-breeding from ice-breeding harbor seals. The ribbon seal (Histriophoca) of the Pacific appears to have evolved from ancestors in the Atlantic like the modern harp seal (Pagophilus) and may have been forced to adapt to a hooded-seal (Cystophora) niche because P. largha preoccupied the harp-seal niche. The gray seal (Halichoerus) of the Atlantic in its turn may have been forced to specialize by the invasion of extant, land-breeding P. vitulina.

A Ribbon Seal from California

A male ribbon seal ( Histriophoca fasciata ) was captured alive near Morro Bay, California on 16 November 1962, and kept on display in a public aquarium until its death 19 December 1962. Observations on the living animal, the freshly dead carcass and the skull are presented, including a brief comparison with a living Phoca vitulina . This seal represents the first North American record of Histriophoca from south of the Arctic Circle, and constitutes a new record for California.

DENTITION OF THE RIBBON SEAL

The dental formula of Histriophoca fasciata is: I 3/2, C 1/1, PC 5 (rarely 6) = 34 to 36. The teeth are rather weak, smooth and distantly spaced. The lower incisors are only half the size of the upper ones and are frequently lost. The lower canines point outward at an angle of 45° from the horizontal. In each half of the jaw, upper and lower No. 1 is the smallest of the postcanine series; Nos. 3 and 4 are the largest; Nos. 2 and 5 are nearly equal. On some skulls the gap between upper postcanines Nos. 4 and 5 is distinctly the widest. The upper postcanines may have a small posterior cusp; the lower ones frequently have both anterior and posterior cusps. In each half of the jaw, upper and lower postcanine No. 1 is single rooted; No. 5 is double rooted; Nos. 2, 3 and 4 are transitional.On one specimen, the third pair of upper postcanines is missing and all of the teeth are unusually small. This skull may be pathological or it may be evidence of the variation to be expected in a declining evolutionary form.Male and female are similar in body size and may reach a length of at least 170 cm. and a weight of at least 95 kg. Cranial measurements of five adult males, one adult female and one adult sex‐unknown are given.

An Unusual Migration of the Spotted and Ribbon Seals

An Unusual Migration of the Spotted and Ribbon Seals

The Art of Sealing Base Metals Through Glass

Methods are described by which base metals may be sealed to and through glass, even though the metal and glass have different coefficients of thermal expansion. The method consists in providing a large surface of contact between the glass and the metal, and in so proportioning the metal that the stresses resulting from the difference in coefficients of expansion are less than the ultimate strength of the joint between glass and metal. Four different types of seals are discussed: First, the flattened wire seal for small electrical conductors. Second, the ribbon seal for special purposes. Third, the disk seal for commercial manufacture of seals for carrying currents of the order of 100 amperes. Fourth, the tube seal in which metal and glass tubing are joined together.

The ribbon seal of Alaska

<i>The ribbon seal of Alaska</i>