PACIFIC SALMON 



55 



cent of these fish which were apparently as 

 much subjected to the influence of the Nass 

 River as were the 65 per cent which went 

 to the Nass, proceeded southward to the 

 Skeena River or northward into Alaskan 

 waters. 



Marking of Pink Salmon 



Marking of pink salmon, i.e., the removal 

 of fins from the young seaward migrants as 

 a means of later identification, has been 

 undertaken in British Columbia primarily 

 to determine directly the age at maturity, 

 and to discover whether the adults return 

 to spawn in the same streams which they left 

 as fry. 



The programs may be divided into two 

 categories, viz., those on the natural runs 

 and those on young fish which were the 

 progeny of eggs hatched artificially. The 

 former include the years 1931, 1933 and 

 1935, when the fry were taken at random 

 from the natural seaward migration in the 

 spring at McClinton Creek, Masset Inlet, 

 marked and allowed to proceed without 

 further interruption. In 1932 and 1936, the 

 fry marked at McClinton Creek were the 

 progeny of eggs transferred to that area 

 from the Tlell River on the east coast of 

 Graham Island. In 1932, some fish were 

 handled at Sweltzer Creek, a secondary trib- 

 utary of the Fraser, which were the result 

 of eggs taken the year previous at the same 

 place, their hatching and the retention of the 

 resulting fry for some months. 



All returns received from the several ex- 

 periments were in the summer and autumn 

 of the year following the marking. The sal- 

 mon at that time were mature and ready to 

 spawn. This is taken as conclusive proof 

 that pink salmon mature and return to 

 spawn in the autumn of their second year. 



Amongst those experiments on the natural 

 runs at McClinton Creek, that begun dur- 

 ing the spring of 1933 was most successful 

 from the point of view of accurate manipu- 

 lation and number of returns and is here 

 discussed in detail as representative of the 

 others. During the spring, 107,949 fry were 

 marked by the removal of both ventral fins. 

 The recoveries, all of which were received in 

 the autumn of 1934 were distributed as fol- 



lows : McClinton Creek, 2,941 ; Masset Inlet 

 fishing areas, 324; Naden Harbor, 1; West 

 coast of the Queen Charlotte Islands, 3; 

 Ogden Channel, 1 ; Whale Channel, 4 ; Bear 

 River, Johnstone Strait, 1, and Deep Bay, 1. 



The recovery in McClinton Creek, the 

 "parent" stream, of 2,941 or 90 per cent of 

 the total recaptured, indicates a strong ten- 

 dency on the part of the pink salmon to re- 

 turn for spaA\Tiing to the stream in which 

 they were hatched. In addition, the 324 

 marked fish taken in the fishing areas in 

 Masset Inlet, the one from Naden Harbor, 

 and the three from the west coast of the 

 Queen Charlotte Islands, might also have 

 reached McClinton if they had not been cap- 

 tured by the fishery. The seven remaining 

 recoveries (one from Ogden Channel, four 

 from Whale Channel and one each from 

 Bear River and Deep Bay) were made so 

 late in the season and in localities so far 

 from the original river that it is unlikely 

 that they could have returned there to 

 spawn. The only possible conclusion from 

 such returns is that the majority of pink 

 salmon in the natural runs will return for 

 spawning to the river in which they were 

 hatched. Isolated individuals may "wan- 

 der" even to a distance of over 400 miles 

 as in the case of the migration from McClin- 

 ton Creek to Deep Bay on the Strait of 

 Georgia, but the number so behaving is 

 economically insignificant. 



The recoveries from those experiments in 

 which fry from transplantation experiments 

 or artificial hatching were concerned, did 

 not prove as consistent in respect to return 

 to the parent stream. From the Tlell fry 

 marked at McClinton Creek in 1932, 40 only 

 were recaptured in the Fraser River fishery. 

 From the 1936 trial, four marked fish re- 

 turned to McClinton in 1937. The recov- 

 eries from the Vedder River marking were 

 located in the Fraser River fishery but no 

 marked individuals were taken at the fences 

 in the Sweltzer itself. It may be that the 

 artificial hatching and consequent transfer 

 of the progeny had an effect upon their later 

 behavior. There are, however, no definite 

 data available at present to support or dis- 

 prove such an assumption. 



