30 



< 



i- 

 o 



1942 1945 

 1943 



947 



J I I I i I i i I I i i I i I 1 



i i i i i 



:tt\ . 



1941 



l i l I l l l l i FN.I I l i 



10 



20 

 AUGUST 



25 



30 I 



10 

 SEPTEMBER 



15 



20 



Figure 4.— Relation of fresh- water survival of pink salmon in Sashin Creek to date by which 50 percent of spawners 

 entered the stream for natural escapements of 1,000 or more, in 17 years from 1940 to 1965 (modified from McNeil, 

 1968). The curve Y= 27.23 - 0.735X Is fitted by least squares; X = corresponds to August 10. The 1966 brood 

 year of the transplanted stock is shown for comparison. 



Some adult pink salmon have entered Sashin 

 Creek every year since observations began, 

 even though four attempts were made to 

 destroy the run in efforts to measure the 

 amount of recruitment or straying from other 

 streams. The apparent maximum number of 

 strays entered Sashin Creek in 1956 when 933 

 adults returned from the parent spawning 

 (1954) of six females and two males, from 

 which 661 fry were counted into the ocean 

 in 1955. 3 



The fresh-water survival of progeny of 

 even-year strays (or a mixture of native 

 fish, i.e., those that originated in Sashin 

 Creek as fry and strays) has always been less 

 than that of the adjacent years of the odd- 

 year line, and usually markedly so. The 

 inability of the even-year line to recover was 



3 Harry, George Y., Jr., and Jerrold M. Olson. 1963. 

 Straying of pink salmon to Sashin Creek, Little Port 

 Walter Bay. Manuscript on file Bur. Commer. Fish. Biol. 

 Lab., Auke Bay, Alaska 99821, 9 pp. 



probably due to a combination of inappro- 

 priate genetic characters (because of a pro- 

 portionally large input of strays) and to the 

 fact that too few eggs and fry resulted from 

 the few adults to escape from severe density- 

 independent mortalities in fresh water and the 

 ocean. Because the 287 fish of unknown origin 

 (see footnote 1) entered Sashin Creek in 1964 

 late (August 30 to September 19), the fresh- 

 water survival of their progeny would be 

 expected to be considerably less than that of 

 the transplanted stock. 



Most (87 percent) of the pink salmon that 

 spawned in Sashin Creek in 1964 were the trans- 

 planted stock, and the adults that returned- in 

 1966 resembled the transplanted stock more 

 than the native stock in three ways. The fish 

 transplanted in 1964 had remained in the ocean 

 until they were nearly ready to spawn and so 

 did the fish of the 1966 escapement to Sashin 

 Creek; most of the transplanted fish spawned 

 soon after they entered the stream, in early 

 September, as did fish of the 1966 escapement; 



12 



