285 



Mr. DiNGELL. You said it was in the early 1960's, but it was not before 

 1959? 



Mr. KiRKNESs. I do not think so. 



Mr. Potter. Let me ask you a few questions about the size of the 

 herd. 



I gather from reading the material that you very kindly furnished 

 me with, that essentially you try to maintain estimates of the size of 

 the herd on the basis of how many pups are born per year; is that 

 correct ? 



Dr. Harry. Yes ; the basis of the returns, how many returns you get 

 from a given pup population, and you adjust this to get the maximum. 



Mr. Pollock. You have a very high mortality rate in your first and 

 second years. 



Mr. DiNGELL. Do you have any population goal at all for seals on the 

 total population from 1956 to 1970 ? 



Dr. Harry. Yes ; I do not have them all in front of me. 



Mr. DiNGELL. Will you submit them to us for the record, please, and 

 give us what you have here ? 



Dr. Harry. We do have them, and they are easily worked out. I do 

 not happen to have them before me right now. I will supply them to 

 you, Mr. Chairman. 



(The information referred to follows :) 



Population Goal of Fur Seal Management Program 



The fur seal management program, as developed in accordance with the Fur 

 Seal Treaty, is to achieve the maximum sustainable yield (m.s.y.). At this time 

 we do not know precisely what m.s.y. is but we have made good estimates and 

 through our management of the fur seal population we are attempting to give 

 more precision to our estimates. Our initial estimate in 1955 of the m.s.y. was 

 approximately 415,000 pups per year. We then began a herd reduction program 

 to reduce the population to the number of females that would produce approxi- 

 mately that number of pups. A subsequent estimate of the m.s.y. required a 

 recruitment of about 480.000 pups per year. That estimate was based, in part, on 

 data which were later found to be invalid and the 480,000 figures was rejectetl. 

 The best present estimate of the m.s.y. is for a pup production of about 400,000 

 pups per year. EHiring the cour.se of the herd re<luction program the annual pro- 

 duction of pups was lowered to around 375,000 pui)s per year. This level was main- 

 tained for several years in order to relate pup production at this level to sub- 

 sequent harvest of males. 



After several years of obtaining information pertaining to the relationship be- 

 tween pup production at this level and subsequent harvest, in 1968 a decision was 

 made by the scientists of the Fur Seal Commission to end this phase of the experi- 

 mentation and to allow the number of breeding females to increase in order to pro- 

 vide a pup production somewhat above 400,000 pups per year. 



Our present program is designed to achieve this goal and since 1969 females 

 have not been harvested commercially. However, the fur seal population cannot 

 respond immediately to changes in harvesting procedures. Females do not reach 

 full productivity until they are about eight years of age, so the complete effect 

 of the ban on killing females is not expected until the mid-1970's. 



Mr. Potter. Eeferring to your 1969 annual report for the Pribilof 

 Islands program, I see that you believed in 1969 that, and I quote: 



The herd can be maintained at this optimum, that is to say, the maximum sus- 

 tainable yield point, by keeping a male-female ratio which will produce around 

 500,000 pups each year. 



I gather you have backed off that now, and you are now estimating 

 that the optimum point is at about 400,000 pups per year, plus or minus 

 50,000. 



