statisticians at the conference to negotiate a 

 new fur seal convention. Some assumptions 

 used in preparing a plan of action were: 



1. The number of females in the Pribilof 

 population was greater than needed to provide 

 a maximum sustained yield, and unless reduced 

 the population would begin to exhibit more 

 drastic fluctuations. 



2. After reduction of the population to a 

 calculated sustained yield point, some females 

 would be available in the harvest each year. 



3. Improvement in the productivity of the 

 population could be measured most quickly by 

 observing the change in land mortality of pups 

 and in the pregnancy rate of females. It would 

 also be observed later in the number of 

 returning seals. 



By fall of 1963, population estimates, sup- 

 plemented by observation of the reduced area 

 of some rookeries and the fewer females on 

 hauling grounds and rookery fringes, indicated 

 that the number of females was sufficiently 

 reduced. Both killing and natural mortality 

 contributed to the lower population. 



Beginning in 1964 the number of females to 

 be taken is the surplus recruitment. This is 

 determined by calculation and by availability. 



The period of reduction was more extended 

 than was desirable and the total amount of 

 reduction was made less clear by fluctuating 

 natural mortality. Methods of estimating popu- 

 lations and monitoring mortality and repro- 

 duction have been improved or made more 

 specific. There is evidence now that the popu- 

 lation level was lower than calculated when 

 the experiment was planned. 



As it enters its second phase, the experiment 

 promises to have interesting and useful results 

 even if the economic return from the fur seals 

 is not increased. Results, such as lower popu- 

 lation estimates and reduced land mortality, 

 are beginning to accumulate, but it is too early 

 to show how these changes are related to 

 reduction of the population. The manipulation 

 of seal numbers required by the experiment is 

 capable of producing concrete evidence on which 

 sound management principles can be based. 



The 1964 field season on the Pribilof Islands 

 extended from June to October. Arrivals, de- 

 partures, and affiliations of research workers 

 follows: 



Name 



Alton Y. Roppel 



Raymond E. Anas 

 Robert L. DeLong 1 

 Willard L. Fairbanks 1 

 Leland P. Glenn 1 

 Mark C. Keyes 

 Charles A. Rohrmann 1 

 Ancel M. Johnson 

 Ford Wilke 

 Dennis Bordukofsky 1 

 David Galaktionoff * 

 Patrick Kozloff 1 

 Agafon Krukoff, Jr. 1 

 Benny Misiken 1 

 Lavrenty Stepetin 1 

 Innokenty C. Lestenkof 1 



Herman Lestenkof 1 

 Dimitri Philemonof 

 Max Thompson 

 Vin Holman 



6 July 



8 Sept. 



Affiliation 



Bureau of Commercial 

 Fisheries 



Work 



Fur seal research, 

 general 



St. Paul Island resident 



St. George Island resi- 

 dent 



Smithsonian Institution Bird banding 



Temporary employee. 



