permanent signs reading "Research Area." Through 1964, 

 dead pups were counted outside, as well as inside, the plots. 



At the end of 1956, after two summers of experimentation, 

 large scale soil treatments for the control of hookworm were 

 abandoned. They were found ineffective, for a reason that we 

 will explain later. 



A temporary employee on St. George Island in 1956 set up a 

 blind near the center of North Rookery and made periodic 

 observations of adult male seals (McGilvrey 1957). He was on 

 watch about 3 h daily during the "pre-breakup" period from 

 30 June to 27 July, and during the "post-breakup" period 

 from 28 July to 24 August. During the first period he saw only 

 one harem bull ousted by an idle bull. During the second 

 period, however, 8 out of 10 matings were effected by idle 

 bulls. He concluded that a management policy which provides 

 for equal numbers of idle and harem bulls at the height of the 

 season in mid-July will insure impregnation of all females in 

 estrus. 



1957 



In April 1957, Karl Niggol joined the staff of the Marine 

 Mammal Biological Laboratory to take charge of pelagic 

 research, a position which he held until he left the Laboratory 

 in 1962. Gary A. Baines started work as a temporary assistant 

 in June 1957, joined as a permanent biologist in 1962, and 

 resigned in 1964. Clifford Hunter Fiscus joined the pelagic re- 

 search team in 1958 and became its leader in 1962 when Niggol 

 left. 



Leo P. Doyle, Professor Emeritus of Veterinary Science, 

 Purdue University, spent the summer of 1957 on St. Paul 

 Island. Through examination of about 1 ,800 dead pups, he ap- 

 praised the causes of mortality such as physical injury, in- 

 herited defects, starvation, and hookworm anemia. "Would 

 these causes eventually change in relative importance as a 

 result of the herd reduction program?" he asked. Doyle stud- 

 ied the "before" aspects in a before-and-after kind of in- 

 vestigation; the "after" aspects are still being studied. The 

 reduction program ended with the killing season of 1963. 



Doyle concluded (1957:9-') that "injuries and starvation 

 were responsible for most deaths . . . before 15 July. After 15 

 July, hookworm infestation was more important. Many path- 

 ological conditions were found but only a few were common. 

 Hookworm, emaciation, ruptured liver, and head injury each 

 caused 10 percent or more of the deaths amoung the pups . . . 

 Salmonella entehtidis was isolated from one of 58 pups ex- 

 amined bacteriologically." Wilke found that the body 

 temperature of a seal pup, especially one in weakened condi- 

 tion, may drop sharply during a rainstorm. In 18 dying pups 

 the rectal temperatures were from 65.1° to 78.4°F, (18.4° to 

 25.8°C) whereas the normal temperature is 100.8°F (38.2°C). 

 Doyle also found in seals the ubiquitous Escherichia coli. 



J. L. Hamerton, of the British Museum (Natural History), 

 found a "diploid chromosome number of almost certainly 

 2n = 36" in fur seal spleen (letter of 17 December 1957). A seal 

 pup on St. Paul Island in July 1957 was treated with colchicine 

 to initiate mitosis. About an hour later, it was killed and its 



spleen removed. Spleen and bone marrow tissues from an 

 adult female killed at the Seattle Zoo on 7 February 1958 were 

 also sent to Hamerton. (The female had miscarried a few days 

 previously.) 



We believe that fur seal blood samples were taken in 1957 

 for George J. Ridgway, Pacific Salmon Investigations of the 

 Fish and Wildlife Service. Others were taken for him the next 

 summer. 



Twelve hundred pups were weighed in late August 1957 on 

 St. Paul Island in the first of a series of measurements of 

 "condition factor" (Fig. 11 bottom). It was hoped that 

 evidence obtained over a span of years would enable the biolo- 

 gists to correlate body condition in late summer with survival 3 

 and 4 yr later. At the end of 1964, however, biologists wrote 

 that "Preliminary studies are not encouraging" (Roppel et al. 

 1965a:22). 



Tagged pups, male and female, proved to be lighter than un- 

 tagged ones. Here was unpleasant evidence that tagging in- 

 duces mortality and that it must be taken into account in any 

 population computation based on tag recoveries. 



Stainless steel trays with 100 compartments were put into 

 use during 1957 for cleaning right upper canine teeth. A "half 

 snout" was placed in each compartment on the killing field; a 

 cleaned tooth was later removed from each compartment in 

 the laboratory. 



As an index of reproductive condition, the presence or 

 absence of milk in the mammary glands was recorded for most 

 females killed in 1957 and 1958. It proved to be a poor index, 

 since it depended largely on individual judgment. It was not 

 used after 1958. 



In their population report, Kenyon et al. (1954) had not 

 discussed the homing tendency of seals, though they had given 

 a breakdown by rookery of the number of A-tagged males re- 

 turning as 3- and 4-yr-olds in 1950-51 (Kenyon et al. 1954:71). 

 Nagasaki and Matsumoto (1957) analyzed the data further and 

 developed equations. They showed that the kill on a particular 

 rookery included from 51 to 81% native males, where 20% 

 would be expected on the basis of chance alone. 



All recent annual reports of research on the Pribilof Islands 

 have included tables on homing. For example, Roppel et al. 

 (1963:24) gave tables on homing according to age, sex, and 

 rookery of birth. The mass of information on homing tenden- 

 cy accumulated since 1951 has not been summarized. 



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 m force 

 from 1912 to 1941. On 9 February 1957, an Interim Conven- 

 tion on Conservation of North Pacific Fur Seals was signed; it 

 came into effect on 14 October 1957 (U.S. Congress, Senate 

 1957; North Pacific Fur Seal Commission 1958", 1964). Its 

 main provisions are listed below. 



■'Doyle, L. P. 1957. Investigation of death losses in fur seal pups on St. Paul 

 Island, Alaska, June 28 10 August 15, 1957. Unpubl. manuscr., 10 p. Northwest 

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

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



■■'North Pacific Fur Seal Commission. 1958. Report of first meeting, .lanuary 

 13th to 17th, 1958. Unpubl. rep.. 18 p- North Pac. Fur Seal Comm., c/o Natl. 

 Mar. Fish. Serv., NOAA, Washington. D.C. 20235. 



42 



