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AFSC Historical Corner:  Northern Fur Seal Research & Management, 1940-59

Early Pioneers
Research and Mgmt.
Species Research
  - Salmon
  - Other Fish
  - Fur Seals 1,2,3,4
  - Whales / Whaling
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  - Invertebrates
Federal Hatcheries
Fisheries Management
Environmental and Ecosystem Monitoring
seal being weighed
A tagged 9 year old male seal weighs in at 415 lb.
Victor B. Scheffer, photographer, 1 July 1949.

The year 1940 is important in fur seal history for three reasons:

1)  By 1940 or thereabouts, the Pribilof seal herd had reached a population plateau. Limited by its natural environment and by commercial cropping, the herd was no longer able to grow. The fact was not recognized in 1940.

2)  On 23 October 1940, the Japanese Government gave formal notice of abrogation of the Treaty of 1911, on the ground that the increased number of fur seals in the North Pacific was causing serious damage to her fishing industry. This break eventually led to a better treaty in 1957 containing provision for a sustained research program.

3)  On 30 June 1940, the U.S. Fish and Wildlife Service was created. As a result, mammalogists and fur seal managers, brought together for the first time in the same Service, were able to take a fresh look at fur seal biology and the fur seal population. Since then (except for the war year 1942), the seal herd has been under continual study by one or more biologists.

The Black Douglas

With the Fur Seal Treaty due to expire in October, the U.S. Government made plans early in 1941 to investigate the food habits and migration routes of fur seals at sea. The main purpose was to find out how many Pribilof-born seals were wintering in waters off Japan, and what they were eating there. The Secretary of the Interior wrote to the [U.S.] President on 7 March 1941 recommending that funds be made available to support a sea-going vessel, a staff of five biologists, and clerical help. The sum of $290,000 was appropriated on 30 June. When funds were appropriated, the following biological staff was assembled: Victor B. Scheffer (in charge), A. Henry Banner, Kelshaw Bonham, Wilbert M. Chapman, Donald D. Shipley, and Ford Wilke. A 3-masted motor vessel, the Black Douglas, was purchased and refitted for pelagic research. When the United States entered World War I1 on 7 December 1941, the vessel was given to the U.S. Navy and all plans for pelagic research were shelved.

In 1947, after the war, plans to reactivate the Black Douglas and to undertake pelagic fur seal research were laid. In 1947, the Black Douglas cruised 17,256 mi (27,771 km) in two trips out of Seattle. The first one took her to the Pribilofs and return, with side trips, from May to August. The second one took her to Attu Island, westernmost of the Aleutians, from September to November.

The Fur Seal Treaty expired on 23 October 1941. By an exchange of notes between the United States and the Dominion of Canada, a provisional arrangement was made on 19 December 1942, in which the United States was to receive 80% and Canada 20% of the annual sealskin take. A domestic Fur Seal Act embodying all important features of previous protective legislation was signed by the President on 26 February 1944. The provisional agreement remained in effect until 1957. An important feature of the 1944 Fur Seal Act was that it provided for the killing of fur seals "for scientific purposes under special permit issued therefor by the Secretary (of the Interior)". It also required each party to report at the end of each calendar year the number of seals taken for research use, and the data obtained from them.


In the spring of 1942, the Aleutian Islands became an active war theater. By military order, the residents of the Pribilof Islands were moved on 16 June and were relocated in Funter Bay, southeastern Alaska. The people were returned in early summer 1944. Fur seal research came to a halt. Wilbert M. Chapman continued for several months to study the bony skeleton of fishes.

1946:  A newborn, 9-lb (4 kg) seal pup was placed in a tank of seawater. It swam vigorously for 20 min, disproving a longheld contention that the pup must be taught to swim.

Sealing was resumed in 1943 under a wartime blackout. The take of 117,164 skins was the largest since the uncontrolled slaughter of the year 1868. Lawrence J. Palmer, a Fish and Wildlife Service biologist with long experience in studies of reindeer, was stationed on St. Paul Island. His main assignment was to record the number of branded male 2- and 3-yr-old seals appearing in drives, and from the resulting data, to estimate the total size of each age group.

Up to 1945, no naturalist had described an early fetus of the fur seal. On 16 January 1945 a fisherman found a seal tangled in his net off the Oregon coast. It was delivered to the Marine Mammal Biological Laboratory in Seattle and found to contain a fetus of 372 g. Scheffer and the first of a long series of summer biologists, Norman O. Levardsen, spent the summer of 1945 on the Pribilofs, mainly in collecting, measuring, and photographing material from known-age seals. On 24 and 25 August they placed large tags, larger than either of those used in 1941, on 973 pups on Tolstoi Rookery. The tags were later found to be successful, though at the time of application, they seemed too large.

Fur seals had long been known to have worms. [Charles W.]Stiles and [A.] Hassal were first to identify the stomach roundworm as "Ascaris decipiens Krabbe, 1878." After examining a collection of worms sent to him in 1946, [H. A.] Baylis reaffirmed (in 1946) that "Porrocaecum decipiens (Krabbe) 1878" is the common stomach worm. At time of writing (1965) we [Scheffer, et al.] believe that Phocanema decipiens is the only ascarid worm recorded from Callorhinus [northern fur seal] in the eastern North Pacific.

Aerial Photography

  balloon photography
An attempt to photograph Polovina Rookery, St. Paul Island, from a captive-balloon camera in 1947.
Victor B. Scheffer, photographer.

The first planned attempt to use aerial photography as an aid in counting seals was made on the afternoon of 9 July 1945. At the request of the Fish and Wildlife Service, the U.S. Navy sent an amphibious plane (PBY) from Adak. The aircraft flew at elevations between 300 and 500 ft (90 and 150 m). A photographer shooting through a hatch in the floor of the tail took at least 83 photographs of St. Paul Island rookeries.

The year 1948 marked an important breakthrough in population studies. On the mornings of 14 and 15 July, in brilliant weather, Scheffer and [K. W.] Kenyon flew over all of the Pribilof rookeries in a twin-engine land plane equipped with an F-56 camera with an 8.5-in lens. They photographed the rookeries from directly above, at elevations of 900 to 1,200 ft (275 to 365 m), and at a ground speed of about 90 mph (145 km/h). On photo enlargements, Kenyon estimated the area occupied by breeding animals and pups on each rookery. From counts made on foot the following year of the number of pups on six sample rookeries, he extrapolated to the total number of pups born in 1949, or 580,000.

In July 1949 a useful technique was discovered by accident. Scheffer had extracted and cleaned the teeth of a bachelor seal and was about to photograph them when he noticed four ridges on the root of each large tooth. Could these correspond to the age of the seal in years? Upon examination of known-age teeth, the answer was "probably." Annual ridges up to about the sixth can be counted on the surface of the seal's tooth. In the late 1950's, biologists Abegglen, Fiscus, Roppel, and Wilke perfected a sectioning technique by means of which at least 26 annual layers can be counted.

Early in 1950, plans were made to tap a new source of research information, namely, pelagic sealing by aborigines. The main objective was to investigate the pregnancy rate of females killed on their winter feeding grounds. A sample taken here should, in theory, be more representative of the female class than one taken on the Pribilof "maternity wards." Throughout history, aborigines living along the west coast of North America have been privileged to hunt fur seals by primitive methods. The aborigines (Aleuts and Indians) are no longer primitive and they rarely exercise the privilege of sealing.

While the need was recognized in 1951 for renewed studies of the Pribilof herd, funds were short and the Fish and Wildlife Service conducted only a modest program of research that year. The old, unsatisfactory laboratory on St. Paul Island was still in use. Its facilities were overcrowded in summer by five collaborators and visiting scientist. Funds being short, only 1,000 seal pups were tagged in 1951. For the first time a plot of breeding ground was marked off as a counting area for estimating pup mortality during summer.

The Three-Nation Investigation of 1952
Canada, Japan, and the United States agreed in 1952 to launch a joint investigation of the distribution and food habits of northern fur seals. The agreement entered into force with respect to the United States and Japan on 8 February, and with respect to Canada on 1 March. The Soviet Government declined [to join] but expressed an interest in reestablishing international arrangements for the conservation of the seals.

Two expeditions were, therefore, organized in February 1952. One using six vessels operated off the coast of northeastern Japan from 19 February to 17 June; the other using two vessels off the coast of North America. Seals were...examined by biologists with respect to presence or absence of a tag or marks, the sex, age (determined by tooth-ridge counts), stomach contents, body length and weight, and length and weight of fetus when present.

The investigation showed that three nations can jointly explore the biological bases for a treaty. It provided North American biologists with a chance to develop a pelagic sealing technique which they were later to use on many occasions.
The Four-Nation Investigations of 1958-64
The long-awaited North Pacific Fur Seal Conference opened in Washington on 28 November 1955. Representatives of Canada, Japan, the U.S.S.R., and the United States met to negotiate a treaty to replace the one which had been in force from 1912 to 1941. On 9 February 1957, an Interim Convention on Conservation of North Pacific Fur Seals was signed; it came into effect on 14 October 1957.

Its main provisions:
  Pelagic sealing was prohibited except for research purposes.

A 6-year cooperative research program was set up to determine the measures necessary to achieve maximum sustainable productivity.

The [U.S. and Soviet] seal harvests were to be shared [with Canada and Japan].

A four-man commission was established.

Studies in the Harvesting of Female Seals, 1953-57

In the early 1950's, biologists concerned with the Pribilof herd realized that it had ceased to grow, yet they were uncertain what changes to recommend in harvesting practice to meet the new situation. They agreed that release of population pressure was called for. One thought was to increase the kill of males by 6% or 7% per annum. Another thought, and the one which was translated into action, called for the killing of females. This proposal would both reduce the herd and correct a possible (?) imbalance of sexes. Steady pressure from the Japanese Government to reduce the herd was still being felt, as it had been in 1941 when the United States cropped an extra 30,000 males. Furthermore, the joint investigation of 1952 had shown that the pregnancy rate of Pribilof seals was low. If due to a low ratio of males to females, some argued, then killing of females would be desirable.

The idea of killing "sacred cows" met resistance at first from the Aleut inhabitants, steeped as they were in the traditions of the islands, and from Fouke Fur Company employees who considered the subadult male Government Alaska Sealskin a "gold standard" among furs. Females were first deliberately killed in 1953 on an experimental basis. The most in a single year, 47,413 were killed in 1957. After 1963 the kill was held to a sustained annual level of about 18,000.

The kill was useful in two ways: it showed that "harem raiding" is a poor way to harvest females and it produced the first good evidence on age, pregnancy rate, and body size among rookery females throughout an entire sealing season. By 1955 the mass of research data including tag numbers recovered from seals, body measurements, and information on reproductive condition, had grown to the point where it called for automatic data processing. Simple Keysort cards were used at first, and in 1957 the IBM system was adopted.

During the 1956 kill, a record was kept for the first time of the color of the whiskers (vibrissae) of females. The purpose was to find an age index which could quickly be spotted on the killing field. The 5-yr-old (entering 6th year) was found to exhibit the greatest variability in color; most younger seals having black whiskers, most older ones white.

Scientific studies of the fur seal received new emphasis in 1956. During the summer...the new laboratory on St. Paul Island was occupied for the first time. On St. George Island, a small laboratory was set up in the hospital, pup tagging was initiated, and a summer biologist was first assigned to the island. More tooth samples were collected in 1956 than ever before. Biologists extracted, cleaned, and counted layers on the right upper canine of about 7,000 males and 4,000 females.

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Early 1960s >>>

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