SYKES and BOTSFORD: CHINOOK SALMON SPAWNING ESCAPEMENT 



Table 3.— Expected [E(bJ] and actual (b w ) numbers of individuals with the specific 

 capture history w and the contribution of the difference between these values to the 

 X 2 test of Seber (1982). The listed capture histories indicate the fish was caught only 

 at those times. 



Table 4.— Expected and actual numbers of individuals caught at 

 sample /' and / (m.«), regardless of their capture history before / and 

 after/, and the contribution of the difference between these values 

 to the x 2 test for equal catchability and survival of Jolly (1982). 



',/ 



E(m 



m 



[Efrn.g) - m. H flE(m.$ 



differential catchability or survival that does exist 

 (as indicated by x 2 tests and differential recapture 

 rates) does not significantly bias resultant estimates. 

 Values of E computed from data "corrected" for 

 age-dependent catchability are presented in Table 

 6. Again, it appears that if age-dependent catch- 

 ability is present, it has little effect on the estimates. 

 Also, that our estimates correlate well with the weir 

 count estimates, whereas "corrected" estimates are 



Table 5.— Estimates of the number of marks released (v,), survival 

 ($;), and the marked population size {n) for the standard Jolly- 

 Seber method and the same estimates (v /t O.,, N. t , respectively) 

 for the test for equal catchability and survival of Leslie et al. (1 953, 

 cited by Seber 1982). 



Sample 



SE V; 



*, 



<t> 



M; 



N 



far too low, indicates that this bias was probably not 

 present in our sampling process. Thus biases en- 

 countered here are insignificant, both in relation to 

 possible imprecision in estimating the percent run 

 and area covererd, and the estimated standard 

 errors. 



Estimates computed to evaluate the effects of 

 lowering sampling intensity are shown in Table 7. 

 Simulations are listed according to the percent of 

 top and the percent of bottom captures ignored for 

 that simulation. The estimates obtained by the third 



267 



