and management of fur seals have, since then, been closely 

 coordinated. 



1961 



A dying, emaciated yearling seal crawled out on the beach at 

 Valdez, Alaska, in January 1961, and a State biologist later 

 autopsied it (Neiland 1961). He found that "it was heavily in- 

 fected with seven species of helminths." He was first to record 

 trematodes (flukes) from the Alaska fur seal; in fact, he found 

 three species: Pricetrema zalophi (Price 1932), Phocitrema 

 fusiforme (Goto and Ozaki 1930), and Cryptocotyle jejuna 

 (Nicoll 1907). Phocitrema sp. had been reported in 1941 from 

 a Commander Islands seal; "fluke eggs" had been found by 

 Doyle (footnote 24) in seal carcasses at the St. Paul Island by- 

 products plant. 



In 1961, Delyamure published a long list of marine mammal 

 parasites, including 12 species from Callorhinus ursinus col- 

 lected in the western Pacific and adjacent seas. None of the 12 

 had been collected in the eastern Pacific through 1964, sug- 

 gesting that American zoologists have much to learn about the 

 parasites of the Alaska fur seal. 



The harvest of bachelor seals in 1961 was very high: 82,197. 

 The poor harvests of the past 4 yr were forgotten; the policy of 

 killing female seals was generally accepted. 



The summer of 1961 brought a breakthrough in the long and 

 discouraging study of hookworm. Lyons and Olsen (1962)" 

 found that the fur seal pup gets its initial infection through 

 mother's milk. Larvae wintering over in the rookery soil are 

 not essential in the life cycle of the worm. 



Olsen (1962:247-250) and Olsen and Lyons (1962) summa- 

 rized the life cycle of the worm. An egg passed in the feces of 

 an infected pup develops to a third stage strongyliform larva, 

 within its egg case, in rookery soil. In late summer it hatches 

 into a free-living third stage larva. Some larvae penetrate the 

 naked flippers of adult female seals and migrate to the belly 

 blubber and mammary tissue. Others winter over in the soil. 

 (In certain years free-living third stage larvae are hard to find 

 in soil in summer or spring.) During the first few days of lacta- 

 tion, larvae enter the mother's milk and pass into the intestine 

 of the nursling. In about 2 wk, or in the latter half of July, the 

 larvae mature in the lower intestine and enter their most 

 destructive phase. This is the only intestinal phase of the 

 worm; it lasts 4 or 5 mo, or until autumn. Almost no worms 

 can be found in the intestine in September. 



An important 3-yr study of the behavior of fur seals on land 

 was started in 1961 by Richard S. Peterson, candidate for 

 degree of D.Sc, Johns Hopkins University. He was attracted 

 to the problem because "fur seals are among the very few 

 mammals in the world whose behavior can be easily observed 

 and documented without disturbance, and [there is] need for 

 knowledge of comparative mammal behavior" (Peterson 

 1962"°). He observed seals from a hut on Kitovi Rookery from 



1 September to 26 November 1961, from 14 May to 26 

 November 1962, and from 12 June to 7 October 1963 (Peter- 

 son footnote 40, 1963", 1964, and in letter of 11 November 

 1964). He developed new and useful techniques for immobili- 

 zing and marking seals, and for defining and categorizing be- 

 havior traits. He marked 1,300 seals, concluding that the best 

 method was to shear a pattern in the pelage and follow with a 

 peroxide foam bleach. Sixteen marked bulls holding inland 

 positions on Kitovi Rookery held their stations from 13 to 77 

 d, with a mean of 47 d (Peterson 1965b:52-54). 



Peterson and Reeder (1966:52) described three twin births in 

 the fur seal— "the first descriptions of multiple births among 

 the Pinnipedia." In one case, the mother delivered twins in 

 captivity. Peterson immobilized her, injected her uterus with a 

 radiopaque fluid, and made a roentgenogram which proved 

 that both pups had been delivered from the same horn. The 

 mother recovered and was released with her pups. She later 

 abandoned them. The authors were unable to find any record 

 of a mother having raised two pups to weaning age. 



In 1961, yearling seals were tagged for the first time, to get 

 evidence on mortality rates from birth to age 1 yr and from age 

 1 to 3. The number tagged was disappointingly low; yearlings 

 were hard to find. Fourteen were known-age (tagged as pups), 

 740 were judged to be yearlings on the basis of size. The sex 

 ratio appeared to be 1 male to 4.3 females, whereas in all 

 previous collections of known yearlings on land in autumn, the 

 males had been more numerous. Suspicion rose that many 

 small females thought to be yearlings in 1961 were actually 

 2-yr-olds. The following year, "twenty-three animals tagged as 

 yearlings in 1961 were recovered from the kill . . . age deter- 

 mination from canine teeth revealed that only one was a year- 

 ling when tagged" (Roppel footnote 37). 



The stomachs of four seal pups were examined at St. Paul 

 Island in October 1961. The contents included sandfish, 

 walleye pollock, smelt, and amphipods. The sample was small 

 but important; it contributed to our still meager knowledge of 

 the weaning food of the seal. 



The question of processing the skins of old female seals con- 

 tinued to be troublesome. Scheffer and Johnson (1963)'^ 

 developed a method for counting the number of fur-fiber 

 bundles per unit area of skin, and for counting the number of 

 fibers per bundle. The results showed nothing unusual about 

 these parameters in females as compared with males. Why old 

 female skins tend to lose fur during the unhairing process is 

 still uncertain. Scheffer (1964) continued the study of pelage 

 fibers and worked out a method making thermoplastic impres- 

 sions of shaved skins. The skin of an adult female seal contains 

 about 300 million fibers. 



Following a study begun in 1958 of the commercial value of 

 female skins, 1 17 skins of females of known ages 2 to 5 yr were 

 collected in August 1961. They were later processed as conven- 

 tional black-dyed skins; 72% of them graded as "Regulars" 

 (Scheffer and Johnson 1962"). For sale purposes they were 



"Lyons, E. T., and O. W. Olsen. 1962. Reporl on the eighth summer of 

 investigations on hookworms. Uncinaha liicasi Stiles, 1901 . and hookworm dis- 

 eases of fur seals, Callorhinus ursmus Linn., on the Pribilof Islands, Alaska, 

 from 7 June to 6 November. 1961. Unpubl. rep., 61 p. Northwest and Alaska 

 Fish. Cent.. Natl. Mar. Mammal Lab., Nail. Mar. Fish. Serv., NOAA, 7600 

 Sand Point WayNE.. Seattle, WA98115. 



'"Peterson, R. S. 1962. Behavior of fur-seal pups during autumn; report of a 

 preliminary study, 1961. Unpubl. manuscr., 59 p. Johns Hopkins University, 

 School of Hygiene and Health. Baltimore, MD 21205. 



"Peterson, R. S. 1963. 1962 summary of fur seal behavior study. Unpubl. 

 manuscr., 9 p. Johns Hopkins University, School of Hygiene and Health, 

 Baltimore, MD 21205. 



"Scheffer, V. B., and A. M. Johnson. 1963. Report on a sample of sealskins 

 taken on St. Paul Island. Alaska, in 1962. Unpubl. manuscr., 20 p. North- 

 west and Alaska Fish. Cent.. Natl. Mar. Mammal Lab., Natl. Mar. Fish. Serv., 

 NOAA, 7600 Sand Point Way NE., Seattle, WA 981 15. 



"Scheffer. V. B., and A. M. Johnson. 1962. Report on a sample of female 

 sealskins taken on St. Paul Island, Alaska, m 1961. Unpubl. manuscr., 13 p. 



48 



