170 



Mr. Leooett. Counsel? 



Mr Spexslev. Dr White, dops that moan that vour interpretation 

 and decision abont depletion is based upon tho third criteria in the 



definition of depletion under the act? 



Dr. Whtte. That is correct. 



Mr. T-eooett. What is tho third criteria? 



Dr. White. When a stock falls below its optimum carrying ca- 

 pacity it is depleted. ■'• B 



Mr. Leooett. So we know, the optimum sustainable population of 

 spinners is what ? 



Dr. White. What. Ave know aro two things about the spinners We 

 have an estimate of the population of spinners which is about 54 

 percent of its original stock. 



Mr. Leooett. How manv numbers is that? 



Dr. White. It is 1.3 million, Mr. Chairman. 



Mr. Legoett. 1.3 million. 



Now. as I understand it, that was your median estimate? 



Dr. White. Yes, in terms of the level of the population. 



Mr. Leooett. So that there would be a ban then, is that true? 

 Would the median be right in the middle? 



Dr. White. There are two factors that must be considered to de- 

 termine whether the stock is depleted. 



One, what is the level of the population ? And the second is. what 

 is the optimum sustainable population? If that level is below the 

 optimum sustainable population, we get into the scientific contro- 

 versy as to what is the lower limit of optimum sustainable popula- 

 tion. 



The optimum sustainable population study group that met in La 

 Jolla pointed out that that lower level is somewhere between 50 and 

 70 percent of the original stock level. 



Some of the scientists believed it was higher than 50 percent and 

 others believed it was around 50 percent. 



Mr. Anderson. 50 percent of what? 



Dr. White. Of the original stock level. 



Mr. Anderson. What is the original stock level ? 



Dr. White. 2.4 million. 



Mr. Anderson. That is the figure that you estimate that there are 

 in existence today? 



Dr. Whtte. Originally, before there was any incidental take of 

 porpoise, it was estimated to be 2.4 million. Now it is 1.3 million. 



Mr. de la Garza. Will the gentleman yield? 



Mr. Anderson. Yes. 



Mr. de la Garza. What degree of accuracy does this figure satisfy? 



Dr. White. There is a degree of certainty. 



Dr. Fox. 1.3 million plus or minus two standard errors would be 

 from 800.000 to 1.8 million. 



The midpoint of the back calculated original stock size was about 

 2.4 million and I believe the range is from 2 to 2.7 million. This is 

 under a set of assumptions in the methodology in making these 

 estimates. 



Mr. de la Garza. A degree of accuracy or inaccuracy of how 

 many? 



