QUALIFICATIONS FOR ABSTENTION 39 



productivity of a stock as it this were some easily defined parameter 

 wliich is characteristic of each stock. This is not true. Even under 

 stable conditions of environment and fishing, the yield of any fish 

 population will vary around some average. The extent of these 

 variations a\ ill depend upon the nature of the species and its fishery, 

 i.e., its rate of growth, rate of recruitment, rate of natural mortality, 

 and the rate at ^\ hich it is being harvested, as well as upon number 

 of year classes. If the stock is characterized by fe^v age classes, or if 

 there are large and long-term variations in recruitment, growth, 

 natmal mortality, or in the conditions of the natural environment, 

 then the population may be very unstable. Even so-called "stable" 

 populations or stocks can show major changes in sustainable yield if 

 changes occur in any of the major popidation parameters. Such a 

 change was noted in the late 1930's in the growth rate of halibut on 

 the Albatross bank in Area 3A (Chapman, Myhre, and South\vard, 

 1962, p. 7). 



Thus, w^hile biologists might be able to prove to their satisfaction 

 that the yield produced in any one year by any stock was the "maxi- 

 mum sustained yield" for that stock, the proof is difficult for some 

 nonbiologists to understand. Moreover, even if the yield were the 

 maximum for that stock, it ^vould only hold in a strict sense for the 

 conditions of that year, and would not necessarily hold for the next 

 or for any other year. Moreover, natural variations could be ex- 

 pected in the productivity of a stock even under constant conditions 

 of environment and fishing, because variation is a characteristic of 

 biological organisms. 



In addition to the above objections to the wording of the treaty, 

 the present state of both theory and measurement of populations 

 precludes the attainment of the accuracy of measurement which 

 would be required to state categorically that any stock of fish was 

 positively producing the maximum amount it could sustain. There 

 may be a wide difference between theoretical calculations and the 

 reactions of natural populations to fishing. 



The term "full utilization" used in Article IV l(b)(iii) is another 

 snare closely associated in theory with maximum sustained produc- 

 tivity. This term has not been defined in the treaty, and is subject 

 to different interpretations. 



In connection with the above analysis of the treaty it should be 

 remembered that there is a considerable economic risk in permitting 



