PLASTIC IMPRESSION TECHNIQUE 

 FOR STUDYING SEALSKINS 



A technique was developed for studying the 

 distribution and diameter of hairs on the sur- 

 face of the skin of fur seals and other pinnipeds. 

 Without resorting to the conventional method 

 of embedding, sectioning, and staining, a 

 thermoplastic impression on transparent film 

 is made directly from the sheared skin. The 

 technique can be used to identify fragments 

 of sealskin found in stomachs of killer whales 

 and sharks, and may also furnish information 

 on the evolution and adaptations of the 2 

 known genera of pinnipeds. A description 

 of the technique is to be published in the 

 Proceedings of the Zoological Society of 

 London. 



EYE LENS WEIGHT AS AN INDICATOR 

 OF AGE 



The dry weight of the eye lens in mammals 

 tends to increase through life. Biologists have 

 used lens weight as an indicator of age of 



rabbits, antelopes, and opossums. Eye lenses 

 of 147 fur seals of known age were weighed in 

 1963. Bauer, Johnson, and Scheffer (1964) 

 showed that lens weight increases geometri- 

 cally in both sexes and is still increasing in 

 the oldest specimens studied, a 14-year-old 

 male and a 21 -year-old female. When only 

 the lens weight and sex are known, the age 

 of a seal can be identified to the nearest 

 year through age 2 only. 



AGE OF THE FUR SEAL PUP AT 

 COMPLETION OF ITS FIRST MOLT 



From a series of newborn pups marked in 

 June 1962, six were killed at ages ranging 

 from 73 to 103 days. A pelage specimen 

 was saved from each. Histological examina- 

 tion of the pelage indicates that the transition 

 from the black coat (late fetal and neonatal) 

 to the silver coat (adult) may be completed as 

 early as 11 weeks after birth and as late as 

 15 weeks, with a mean of about 13 weeks. 

 The mean completion date is about 7 October 

 (Bauer, Peterson, and Scheffer, 1964). 



OTHER WILDLIFE SPECIES 



SEA LIONS 



The number of sea lion pups tagged on 

 Walrus Island in 1963 is given in table 44 

 with those tagged in previous years. 



No tags have been recovered from sea 

 lions tagged as pups in 1959 and 1960 even 

 though a reward of $5 is offered. One fur 

 seal pup was seen on Walrus Island in 1963; 

 adult fur seals were not observed. 



Table 44. — Sea lion pup tagging, Walrus 

 Island, 1959-60 and 1963 



1 Tags within the range of numbers given 

 were used. 



WHALES 



Two dead whales drifted ashore on St. Paul 

 Island in 1963, an adult sei whale ( Balaenoptera 

 borealis) and a newborn pilot whale ( Globi - 

 cephala scammoni ). One unidentified whale 

 drifted ashore on St. George Island. 



WALRUS 



One adult female walrus drifted ashore 

 dead on Staraya Artil Rookery, St. George 

 Island, April 1963. 



SEA OTTERS 



Through the courtesy of the Commanding 

 Officer of the Coast Guard Cutter Northwind, 

 the ship's helicopter was used 6 July to search 

 for survivors of a 1959 transplant of sea otters. 

 Two biologists were aboard as observers. The 

 island was circled completely at a distance of 

 from 100 yards to perhaps a mile off shore. 

 Kelp beds in particular were examined but no 

 sea otters were observed. 



REINDEER 



The helicopter was also used on 6 July to lo- 

 cate and photograph the reindeer herd. The herd 

 was in two groups, one containing cows and 

 calves and the other containing mostly bulls. 

 The total count of reindeer on the photographs 

 was 537. This figure agreed closely with a count 

 of 550 obtained from the ground a month earlier. 



Parts of the island are showing effects 

 from overgrazing by the reindeer herd. The 

 productivity of the island and the reindeer 

 herd will both be maintained best by regular, 

 severe cropping. Management officials will 

 make a separate report on the reindeer. 



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