52 



THE MIGRATION AND CONSERVATION OF SALMON 



cated migrations off the coast of British 

 Columbia usually in a south and easterly 

 direction. Especially noteworthy is the re- 

 capture of two individuals in the Sacra- 

 mento River, 800 miles from the point of 

 tagging. 



2. This habit of travelling long distances 

 exposes the fish to capture at many points 

 and greatly increases the difficulties in- 

 volved in measures of regulation. As an 

 illustration, spring salmon tagged off Bark- 

 ley Sound were taken off Barkley Sound, in 

 the Strait of Juan de Fuca, in Puget and 

 Washington Sounds, off the coasts of Wash- 

 ington, Oregon, and California and in the 

 Columbia River. 



3. The migrations are definitely interna- 

 tional in aspect. In the case under consid- 

 eration from tagging in Canadian waters 82 

 per cent of the returns were from territory 

 of the United States. 



When a summary of recoveries for all the 

 tagging programs on the species is set up 

 showing the percentage return for the 

 Fraser River, the Columbia River, Canadian 

 waters and United States waters, exclusive 

 of Alaska, it is evident that as the location 

 of the tagging base becomes more northerly, 

 the returns from the waters of the United 

 States, exclusive of Alaska, become fewer, 

 those from the west coast of Vancouver 

 Island averaging approximately 85 per cent, 

 from the west coast of the Queen Charlotte 

 Islands approximately 66 per cent, and from 

 the north coast of the latter together with 

 Hecate Strait, 53 per cent. Coincident with 

 this change the recaptures in Alaska in- 

 crease from none for the west coast of Van- 

 couver Island to as high as 4 and 2 per cent 

 for the west and north coasts of the Queen 

 Charlotte Islands, respectively. Such a con- 

 dition presupposes that the individuals 

 which constitute the commercial spring sal- 

 mon fishery have come from the north and 

 west and are proceeding toward the south 

 and east. 



Consideration of the data with special 

 reference to the time of recapture in relation 

 to the time of tagging is also of interest. 

 Our present knowledge of salmon habits and 

 the location of recoveries in the experiments 



would definitely indicate that those fish 

 which were recaptured in the year of 

 tagging were closely approaching maturity 

 at the time of tagging, while those taken in 

 each succeeding year represented greater 

 and greater degrees of immaturity at the 

 time the tag was affixed. On this basis the 

 fish from Seal Inlet and other northern areas 

 where a lower percentage return was re- 

 ceived in years subsequent to tagging, were 

 more mature than those at Barkley Sound 

 in the south. At North Island on the north 

 coast of the Queen Charlotte Islands an indi- 

 cation of immaturity again appears. This 

 is explicable, as shown later, by the assump- 

 tion that fish of another river system are 

 involved. 



The examination by Dr. C. McC. Mottley 

 of the scales from the fish tagged off Barkley 

 Sound in 1926, and Kyuquot in 1927, and 

 comparison with similar determinations 

 made by Dr. Willis H. Rich for fish off the 

 mouth of the Columbia River in 1925, have 

 led to the assumption that the numbers in 

 the older age groups increase as the location 

 moves northward and westward. Confirma- 

 tion of this was forthcoming from qualita- 

 tive observations which indicated a wave of 

 young fish passing northwestward, produc- 

 ing a crest of abundance off Barkley Sound 

 in June and off Kyuquot in August. 



The tabulation of the weights of the fish 

 tagged definitely shows that the size in- 

 creases in the more northerly areas, at least 

 up to Seal Inlet on the west coast of the 

 Queen Charlotte Islands. In the northern 

 areas most of the individuals are in the 30 

 to 50 lb. group while at Barkley Sound the 

 mode lies in the 10 to 19 lb. group. This is 

 again an indication of increasing age toward 

 the north. 



From these- pieces of evidence, namely the 

 distribution of the returns from the tagging 

 programs with the decreasing numbers from 

 southern rivers for northern tagging bases, 

 the increase of maturity toward the north, 

 a similar increase in weight and age, and the 

 results of marking programs by Dr. Rich 

 and Mr. H. B. Holmes on young spring sal- 

 mon in the Columbia in which they demon- 

 strated that the fish returned to the stream 



