Table 10. — Estinates of sxirvival of pink salmon of the 1963 brood year during 

 four periods in three areas in Sashin Creek 



In computing values of Kl, the unit of time 

 is tziken as 1 month. Thus,^ = 1,5 for period 

 1; 2.5 for period 2; 3.5 for period 3; and 2.0 

 for period 4. Values of Sjn used to connpute M 

 (equation 7) are taken directly from table 10. 

 The connputed values of M_ for each area 

 and time period are given in table 11. 



Table 11. — fetimated instantaneous mortality 

 coefficients during four periods^ in the 

 life of pink salmon of the 1963 brood year 

 in three areas in Sashin Creek 



18 



■"■ Tlie periods are: (1) E^g deposition (mid- 

 August to late Septenfcer ), (2) egg deposition 

 to hatching (late Septenfcer to mid -Dec ember), 

 (3) hatching to fry emergence (mid-Deceirber 

 to late March), and (4) fry emergence and 

 migration (late Ifarch to late Iifey). 



Changes in the number of live eggs and 

 alevins within each area and in the entire 

 stream are shown in figure 1, For the entire 

 stream, numbers declined nnost during spawn- 

 ing and least during emergence and migration 

 of the fry. The sequence of nnortality before 

 the fry emerged differed among the three 

 areas. The decline in numbers in the upper 

 area was less pronounced than in the nniddle 

 and lower areas during period 1 but more 

 pronounced during period 2, The only distinct 

 decline in nunnbers during period 3 was in 

 the lower area. 



The differences in the density of fry in the 

 three areas were marked. The number of fry 

 per square meter was 360 in the upper area, 

 268 in the nniddle area, and 174 in the lower 

 area. Because of the differences in size of 



16 - 



14 



ii2 



Z 

 _i 

 4 

 tn 



I ^ 



a. 



<^ e. 

 < 6 



■BEGINNING OF SPAWNING 



i ENTIRE STREAM 

 o UPPER AREA 

 • MIDDLE AREA 

 A LOWER AREA 



BEGINNING OF 

 FRY MIGRATION 



AUG 



I I " 



SEPT O 



L! i : ' ;j 'i : 



t'^f^ 



OCT NOV. DEC. I JAN. FEB. MAR. APR. MAY JUNE 

 1963 1964 



Figure 1 — Number of viable pink salmon of the 1963 

 brood year in three areas of Sashin Creek and in the 

 entire stream, at beginning and end of four periods in 

 fresh water. 



the areas, each area produced about the same 

 total number of fry. 



SUMMARY AND CONCLUSIONS 



In 1963, spawning pink salmon in Sashin 

 Creek failed to concentrate in the upper 

 area of the spawning ground, which appeared 

 to afford excellent habitat for embryos and 

 alevins. The steep gradient and coarse 



