56 



THE MIGRATION AND CONSERVATION OF SALMON 



Marking of Sockeye Salmon 



For sockeye salmon a comprehensive 

 study of the migration, in so far as it per- 

 tained to the return from the sea, of a popu- 

 lation native to Cultus Lake, British Colum- 

 bia, was made in the years 1930 to 1934. 



In the spring months of 1930 and 1931 all 

 the seaward-migrating sockeye leaving the 

 lake were marked. In 1930, 104,061 were 

 so treated by having the two pelvic fins re- 

 moved ; in 1931, from all of the 365,265 in- 

 dividuals migrating the two pelvics and the 

 adipose were amputated. These fish were 

 then liberated to pass on downstream and 

 eventually to the sea. 



Returns from the 1930 marking were ex- 

 pected in 1931, 1932 and 1933 as three, four 

 and five-year-old fish respectively, while 

 recoveries of the 1931 group were antici- 

 pated in 1932, 1933 and 1934. Accordingly, 

 in these several years arrangements were 

 made to have all or the greater portion of 

 the sockeye landed at the various canneries 

 throughout the fishing areas of the State of 

 Washington and British Columbia closely 

 examined for fish with missing fins. Ob- 

 servers were employed at the necessary 

 points for this sole purpose. During the 

 same years the records of marked fish re- 

 turning to the parent spawning ground, 

 Cultus Lake, were kept and, in addition, 

 requests were issued to fisheries officers and 

 others throughout the Fraser River system 

 to keep close watch for the presence of 

 marked sockeye among the spawning popu- 

 lations of other areas. 



From the fishing areas came very signifi- 

 cant returns. Commencing with the purse- 

 seine fishery on Swiftsure Banks, off the en- 

 trance to the Strait of Juan de Fuca, the 

 first point adjacent to the open ocean at 

 which migrating adult sockeye are caught, 

 and continuing on in through the Strait of 

 Juan de Fuca, the waters of the San Juan 

 Archipelago, Rosario Strait, the lower end 

 of the Strait of Georgia, to the Fraser River, 

 marked sockeye in all the years in question 

 were recovered. The numbers of marked 

 individuals obtained in 1932 and 1933, ar- 

 ranged according to date and area of cap- 

 ture, are shown in the accompanying table. 



TABLE III 

 Eecaptured Individuals, 1932 and 1933 



" 05 







fl S 2 s 



w ^ GO ' 

 O O ^H .S 



PhM few 



The trend of migration of the Cultus Lake 

 sockeye seems, accordingly, well defined. 

 Passing seaward from the lake, at an age of 

 one year from hatch, the young fish enter 

 the ocean and presumably proceed off Van- 

 couver Island to the west or northwestward. 

 There they remain from one to three years 

 — the majority return after two — when, 

 with advancing maturity, they commence 

 their return journey. There can be no ques- 

 tion of their lingering during the ocean 

 period of residence in coastal or gulf waters 

 for in such case they would be picked up in 



