A major part of the hunting success of any 

 vessel depends upon the helmsman's ability 

 to follow a seal and, when a seal is killed, to 

 bring the vessel alongside in the least pos- 

 sible time. Skill in these functions increases 

 the number of seals killed and decreases the 

 number lost by sinking. 



Small boats ran courses paralleling the 

 vessel at distances up to half a mile. Hand- 

 held radios were first used in 1962 to co- 

 ordinate vessel and small boat movements and 

 to improve safety. 



Each boat was manned by two men. One 

 operated the motor, and the other did the 

 shooting. Seals were taken from the small 

 boats more easily and with fewer losses than 

 from the vessels because of the former's 

 maneuverability and quick changes of speed. 

 Also, the seals allowed small boats to ap- 

 proach more closely. 



Seals were shot with 12-gauge shotguns 

 using magnum loads of 00-buckshot. Success 

 in collecting seals with a .243 caliber rifle 

 with telescopic sights was poor. 



A rough log was kept of time and courses 

 run, course changes, and loran and radio- 

 direction finder bearings. The rough log also 

 included time records of seals sighted and 

 surface water temperatures taken at collec- 

 tion points. Numbered aluminum tags, attached 

 to the seals as they were brought aboard, 

 maintained identification of the specimens and 

 related them to pertinent data. Other notes on 

 navigation and position of the vessel, and posi- 

 tions of other marine mammals sighted, were 

 also entered in the rough log. At the end of the 

 hunting day, the day's run and the positions 

 of all marine mammals seen and collected 

 were plotted. Data from the rough log and the 

 plotted positions were transferred to the 

 daily work sheets to complete the record. 



Field Examinations 



When a seal was examined on the deck it 

 was first checked for tags, checkmarks, 

 brands, or external abnormalities. The seal 

 was weighed in kilograms and measured in 

 centimeters (tip of nose to tip of tail). The 



snout was skinned out and removed with large 

 lopping shears. The right half of the snout was 

 saved in a cloth bag with an aluminum speci- 

 men-tag bearing numbers correspond- 

 ing to the tag attached to the body. The left 

 half of the snout was discarded. Later, the 

 right half of the snout was boiled and the upper 

 right canine tooth removed. The seal was 

 opened, and the reproductive condition noted. 

 The sex, length, and weight of any fetus 

 present were recorded. Macroscopic exami- 

 nation of the uterine horns and ovaries was 

 made on all females. When the reproductive 

 condition was questionable the specimen was 

 labeled and preserved. 



The stomach was tied above the cardiac 

 sphincter and below the pyloric sphincter, 

 then cut free from the esophagus and intestine. 

 The tag on the body was transferred to the 

 stomach. The stomach was injected with 10 

 percent formalin and stored in a barrel of 

 formalin. 



Laboratory Methods 



Ages of all seals collected are determined 

 by making longitudinal sections of the canine 

 teeth and counting the internal annuli. Scheffer 

 (1950) first described age estimation by growth 

 layers on the external surface of teeth; how- 

 ever, these external layers may be counted to 

 estimate age up to about age 10, but after that 

 age the layers tend to become obscure. Longi- 

 tudinal sectioning and the counting of internal 

 annuli make it possible to determine age of 

 old seals that previously could only be placed 

 in a general category, which included all teeth 

 from seals over 10 years old. 



A preliminary section of a tooth is made by 

 cutting the tooth lengthwise, just off the center, 

 with a bandsaw. A sliding tooth holder was 

 developed for this operation. A horizontal 

 grinding wheel of coarse abrasive is used to 

 grind the rough surface to the midline. Sub- 

 sequent use of a fine abrasive wheel removes 

 scratches on the cut surface and prepares the 

 tooth for final polishing on a felt wheel to which 

 water and polishing compound have been added. 

 Each tooth is polished until all dull areas 



By C. E. Abegglen and A. Y. Roppel. 



