Table 6. — Survival of even- and odd- numbered brood year pink salmon in 

 Sashin Creek, 1940-63 (Data from Olson and McNeil, 1967) 



Number 



Number 



Percent 



Number 



Number 



Percent 



Mean survival — 



2.5 



9.5 



Grand average = 6.3 percent 

 •"•No escapement. 



Early entry of pink salmon into Sashin Creek 

 is accompanied by early spawning because 

 most of the fish have matured before they 

 enter the creek. Early stream entry in the 

 past has been followed by higher survival of 

 eggs and alevins thanlate stream entry (McNeil, 

 1968). Merrell (1962) thought that eggs de- 

 posited early get a "head start" before cold 

 weather retards development during the sensi- 

 tive period immediately after fertilization. 

 The observations of Azbelev, Surkov, and 

 Yakovenko (1962) support this contention. 



Survival from the 1966 spawning was also 

 high (about 12 percent of potential egg deposi- 

 tion). About 750,000 fry migrated to sea in the 

 spring of 1967 (Ellis, in press). Thus, the 

 long-standing scarcity of pink salmon of the 

 even-year line in Sashin Creek now appears 

 to have been reversed. Figure 3 shows the 

 decline of spawners from both odd- and even- 

 year lines in the 1940's, the recovery of the 

 odd-year line in the late 1950's, and the very 

 recent recovery of the even-year line through 

 transplantation. We recognize that attempts to 

 annihilate the even-year line in 1950, 1952, 

 I960, and 1962 may have prevented the natural 

 recovery of the even-year line. 



RECOMMENDATIONS 



Vessels equipped with large tanks for re- 

 frigerated sea water (brine boats) are now 

 commonly used in Alaska to transport com- 

 mercial salmon catches to canneries. Success- 

 ful introduction of adult pink salmon to Sashin 



Creek in 1964 demonstrates that it is feasible 

 to use these vessels to transfer seine-caught 

 pink salnnon to streanns where fish are scarce. 



The experiment described in this paper was 

 done to develop and test techniques, and we 

 caution against indiscriminate transplantations 

 of fish, because of the possibility of undesira- 

 ble effects from the mixing of genetically dis- 

 similar stocks. If a recipient stream is nearly 

 devoid of spawners (as was Sashin Creek), 

 we foresee little danger from such inter- 

 breeding. If the recipient stream possesses 

 a significant native population of spawners, 

 one gambles with the possibility of introducing 

 unfavorable genetic characteristics. Under 

 these circumstances, we would favor an at- 

 tempt to rebuild the native population by pro- 

 tecting it from the fishery rather than by 

 introducing spawners from another streann. 

 Should knowledge of genetic characteristics 

 of populations become adequate, it might 

 someday become feasible to substitute geneti- 

 cally superior populations of pink salmon for 

 native populations. 



To increase the chances of success in re- 

 building pink salmon runs by transplantation 

 of adults, the native and introduced fish should 

 be similar in terms of timing of migration and 

 spawning. It nnight also be desirable for tem- 

 perature and other characteristics of spawning 

 beds of the donor and recipient streanns to be 

 similar, because failure to establish a run 

 might result from genetically determined in- 

 ability of an introduced stock to adapt to a new 

 environment. 



