Karl W. Kenyon

The Sea Otter

In general form the sea otter, Enhydra lutris resembles the weasel and river otter, of which animals it is a large relative. The male attains a weight of 85 pounds, the female about 65 pounds; the young at birth weigh from 3 to 5 pounds. It is peculiar among members of its family, the Mustelidae , in having deserted dry land and fresh water to take up a marine life. Among marine mammals it is peculiar in its adaptation to the sea. It does not possess an insulating layer of blubber but is protected from the chill of North Pacific waters by a blanket of air trapped among the fine and closely packed fibres of its inch-long delicate fur. Unlike the river otter and fur seal, the sea otter has but little protective coating of guard hair. The fine guard hairs present add to its beauty but do not offer much protection to the soft under-fur. Unlike other maring mammals, the sea otter has never taken to the open sea. It usually feeds in shallow water from 5 to 50 feet in depth. Its food consist primarily of such sedentary forms as sea urchins, rock oysters, mussels, a variety of snail-like molluscs and, in California, abalones. Occasionally fish and octopus are eaten.

Abundance and Distribution of the Steller Sea Lion

Observations of the Steller sea lion, Eumetopias jubata , including hauling-out habits, seasonal movements, and aerial surveys in eastern Bering Sea from Bering Strait to and including the Aleutian Islands, are presented. Sea lions haul out during winter and spring, prior to the breeding season, in greater numbers in afternoon hours than in morning hours; few haul out during storms. The dearth of animals seen in the water during aerial surveys indicates that the great majority are hauled out during fair weather in the spring. The Pribilof Islands are the northernmost breeding grounds but a number of animals, probably adult and sub-adult males, migrate north in late summer and early fall. As many as 1,000 regularly reach St. Lawrence Island and a few reach Bering Strait. These animals move south again with the advance of ice in the fall but ice does not cause them to desert the Pribilof Islands. Certain hauling grounds within the breeding range are used seasonally. Aerial surveys of all Aleutian Islands and areas near the end of the Alaska Peninsula in 1959 and 1960 revealed 98 rookeries and hauling grounds with an estimated total of about 100,000 animals. The total world population of this species, based on the present report and on previously published data, is estimated to be about a quarter of a million animals.

Man Versus the Monk Seal

Surveys of monk seals at Midway and Kure Atolls in 1957 and 1958 are compared with surveys of the same areas in 1968, 1969, and 1971. Where 68 seals were seen in 1957 and 1958 at Midway, only one seal was seen in 1968, four in 1969, and six in 1971. Before Kure was occupied by man in the early 1960s, the majority of seals used Green Island as a pupping and hauling ground. Few seals came ashore on Green Island in 1968; instead they used isolated, shifting sandspits. Observations indicate that the Kure population is declining. Evidence is presented that mans repeated disturbance of seals on beaches may increase juvenile mortality and cause seals to desert the beaches offering preferred habitat. In 1957 and 1958, the monk seal bred on six atolls of the Leeward Hawaiian Islands; by 1968, it bred regularly on five. It is postulated that during this 10-year period about 6 per cent of the world population of this seal disappeared. A recent report (1971) indicates that the monk seal is attempting to recolonize isolated islets at Midway Atoll.

Population Status of the Hawaiian Monk Seal (Monachus schauinslandi), 1978

Hawaiian monk seals, found in the northwestern Hawaiian Islands, regularly haul out and give birth on the beaches of six atolls, regularly haul out but rarely give birth on three additional islands, and are seldom sighted elsewhere. Since 1958, counts of monk seals have indicated a decline in population of about 50%. The population of the westernmost atolls, Kure, Midway, Pearl and Hermes Reef, and Laysan and Lisianski islands, have all declined; the population at the only other major pupping atoll, French Frigate Shoals, increased dramatically from 1957 to 1975 and now appears to be stable. The primary cause of the decline, at least at some atolls, has been increased mortality in early life; however, only some of the factors causing the increase in mortality are known. Predation by sharks has been identified as a cause of mortality, and increased human activity was followed by a decline in seal population on two atolls. In 1978, high mortality, which may have resulted from ciguatera or gastrointestinal parasitism, occurred primarily at Laysan Island. Ciguatera is a disease caused by Ciguatoxin produced by a dinoflagellate; this toxin accumulates in prey species of monk seals, such as eels and other fishes. Even though it has been 15 or more years since the monk seal populations declined at Kure Atoll, Midway Island, and Pearl and Hermes Reef, there is no evidence of their recovery.

Birds from the Pribilof Islands and Vicinity

THIS paper reports unusual species of birds collected or observed on the Pribilof Islands (St. Paul, St. George, Otter, and Walrus islands) and records observations of interest concerning some resident species of the Pribilofs. Observations from the Aleutian and Commander islands are included. Preble and McAtee (1923) summarized available knowledge of Pribilof birds. We here attempt to record only pertinent information obtained in recent years. Our data were collected primarily from 1947 to 1954. In this period Kenyon spent a total of 21 months on the Pribilofs, mostly from May to October. Phillips was on the Pribilofs from 19 June to 24 September 1954. Ornithological observations were made sporadically, incidental to full-time work on studies of Alaska fur seals (Callorhinus ursinus). The data presented represent only a minor fragment of what is needed for an understanding of the ecology and distribution of Pribilof birds. No continuous, long-range studies have been undertaken in this area, although ecological conditions at the Pribilofs are of interest. For example, both the Common Raven (Corvus corax) and Pigeon Guillemot (Cepphus columba) are resident on islands north and south of the Pribilofs, yet neither breeds on the Pribilofs. The raven rarely occurs there and the guillemot is present only in winter months. The Winter Wren (Troglodytes troglodytes) is a common resident of St. George Island. It appears irregularly on St. Paul and Otter islands. Possibly it breeds in some seasons on St. Paul and was established at one time on Otter (Hanna, 1920b). Growth of marine mammal populations has particularly affected populations of the Glaucous Gull (Larus hyperboreus), Glaucous-winged Gull (L. glaucescens), and the Common Murre (Uria aalge). As fur seal and sea lion (Eumetopias jubatus) populations increased in recent years, bird nesting areas were usurped as mammalian breeding grounds. As Hanna (1920a: 248) pointed out, the Pribilofs are ideally situated as a stopping place for birds from many areas. A number of species were added to the North American list on the basis of specimens collected on the Pribilofs. That more could be, and still are being, added is indicated by several observations of unusual birds which could not be collected or identified in the field. Among the 34 forms here listed, 1 (Apus apus pekinensis) is a new record for North America; 9 (Charadrius mongolus, Capella gallinago gallinago, Ereunetes mauri, Larus ridibundus, Aegolius funereus richardsoni, Progne subis, Bombycilla garrula pallidiceps, Dendroica coronata

Cuvier Beaked Whales Stranded in the Aleutian Islands

Two Cuvier beaked whales, Ziphius cavirostris , a. female (USNM No. 288019) and male (USNM No. 288020), were found on beaches of Amchitka Island, Alaska, in March and April 1960. The female was fresh, the male considerably decomposed. This is a widely distributed but uncommon species. The skulls of both animals were preserved. Rifle fire appeared to have caused death. The female weighed 2952.5 kg and measured 658 cm in standard length; the male was 543.5 cm long. The sectioned teeth of the female revealed 24 to 28 growth layers, of the male 13 layers. Presumably each layer represents one year of life. Examination of the ovaries revealed five small follicles and one (possibly two) corpora albicantia. The stomach of the female contained the remains of 1,304 squids and the immature stage of a species of Anisakis , a parasitic nematode. Little is yet known of the biology of this whale.

History of the Steller Sea Lion at the Pribilof Islands, Alaska

In 1786 the Pribilof Islands probably supported a sea lion population considerably in excess of 15,000 animals. These bred on two rookeries on St. George Island, one on St. Paul Island, and one on Walrus Island. A few may have bred also on Sea Lion Rock. The Walrus Island colony disappeared in 1827; between 1867 and 1914 both St. George rookeries were exterminated, and the St. Paul rookery was reduced to less than 150 animals. A measure of protection was given the sea lion in 1914. By 1960, the population had increased to 5,700–6,700 adults. The only breeding ground today on the Pribilofs is on Walrus Island, where about 3,000 young were born in 1960. Newborn pups were last seen on St. Paul Island in 1957. All extinct rookery sites are now regularly used as hauling grounds. Otter Island, never a breeding ground, is a regular winter hauling ground. Unregulated exploitation and harassment by man probably played an important role in the reduction of the Pribilof sea lion herd and the shifts in rookery locations. The failure of the Pribilof population to approach its aboriginal size and to reoccupy old breeding grounds during a 40-year period of moderate exploitation is unexplained. Unknown ecological factors are suggested as a contributing cause.

Notes on Phocid Seals at Little Diomede Island, Alaska

has been published earlier (Buckley, 1958; Kenyon, 1960). The 21 families (approximately 100 resident Eskimos) of Ignaluk depend for existence primarily on the Pacific walrus (Odobenus rosmarus divergens), and secondarily on the ringed and bearded seal. In order to observe conditions relating to conservation of marine mammals, particularly the walrus, a U. S. Fish and Wildlife Service study was instigated by the late Clarence J. Rhode, Regional Director for Alaska, and was undertaken by the late Stanley S. Fredericksen, Game Management Agent, and the author. The material presented here was recorded during that study. Also included is additional information from reports of Bureau of Indian Affairs schoolteachers. Thanks for cooperation are extended to the Little Diomede Eskimos and Mr. and Mrs. Donald Abbott, Bureau of Indian Affairs schoolteachers; Leo Margolis, who identified the helminth parasites; G. Dallas Hanna and Miss Patsy A. McLaughlin, who identified representative samples of invertebrates found in seal stomachs; N. J. Wilimovsky, who identified fish remains; and F. H. Fay, who contributed advice on the manuscript.

The Pacific Walrus

The U.S. Fish and Wildlife Service announced a 12-month finding on a petition to protect the Pacific walrus (Odobenus rosmarus divergens) as endangered or threatened and to designate critical habitat under the Endangered Species Act (ESA) of 1973, as amended. After review of the best scientific and commercial information available, the Service finds that protecting the Pacific walrus as threatened or endangered is warranted. Currently, however, adding the Pacific walrus to the Lists of Endangered and Threatened Wildlife and Plants is precluded by the need to address higher priority species. Upon publication of this 12-month petition finding, the Service will add Pacific walrus to the candidate species list. As priorities allow, the Service will develop a proposed rule to list the Pacific walrus that is subject to public review and comment. The Service will make any determination on critical habitat during development of the proposed listing rule. In the interim, the Service will address the status of the Pacific walrus through the annual Candidate Notice of Review.

Food of Fur Seals Taken on St. Paul Island, Alaska, 1954

made from it reveals that doe milk has, in the nutritional sense, twice the quality of cow milk. As already pointed out, this is associated with rapid growth of the fawn. In a wild species, particularly one in a northern latitude, rapid early growth is an important contribution to survival through the subsequent winter. Two possible sources exist for nutrients to produce milk of the quality indicated. Under relatively ideal conditions the doe can rely upon its dietary intake. It is likely, however, that under most field conditions recourse must be had to withdrawal of nutrients from the body reserves. While it is recognized that nutritional conditions in the wild are usually approaching the optimum at the time of birth, it is well to point out that the does condition is likely to be poor as a result of the strain of gestation coupled with food shortage or rigorous weather during the winter. Her reserves may be small or non-existent.