105 



population abundance required Co meet the stability objective and 

 provides the necessary comparative values for the comoined- 

 effects analysis, 2) the expected number of spawners at the end 

 of the analysis period ;5-year average fcr 2004-2008), and 2) fi , 

 the final instantaneous rate of change in the population. Table 

 2 summarizes how these parameters vary depending on the specified 

 level of confidence. 



The goal of the analysis is to determine the likelihood that the 

 combined effects of all actions would stabilize the abundance of 

 the listed species. The tabulated confidence levels are 

 equivalent to the probability that the 2004-2008 average 

 escapement will be equal to or greater than the average observed 

 from 1986-1990. However, it is pertinent m understanding the 

 analysis to point out that, if the expectation of population 

 stability after four life cycles were achieved, the chinook 

 salmon populations would be expected to have positive growth 

 rates once the measures are implemented and take full effect on 

 eacn phase of the brood cycle. Selection of a higher confidence 

 level would increase the degree cf certainty aoout meeting the 

 objective. However, it also would result in an expectation that 

 population growth rates at the end of the analysis period could 

 be quite high and that the number of spawners at the end of the 

 analysis period would be substantially higher than during the 

 1986 to 1990 base period (Table 2) . 



The objective of the combined-effects analysis is to determine 

 whether mortality reductions resulting from proposed improvements 

 are sufficient to be likely to stabilize the populations at base 

 period levels. Although it is necessary for NMFS to make a 

 determination as to the sufficiency of mortality reductions at 

 this time, it is also true that NMFS will continue to evaluate 

 circumstances and modify actions as necessary to ensure that the 

 actions will not likely jeopardize the continued existence of the 

 listed sDecies. 



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