INVESTIGATION OF THE SALMON AND SALMON RIVERS OF ALASKA. 



PHYSICAL CHARACTERISTICS OF THE ENVIRONMENT OF THE SALMON. 



KAKLTJK BAY. 



(Plates v-xiv.) 



The marine life of the Alaskan salmon is entirely unknown except when the vari- 

 ous species approach the mouths of certain rivers to asceud to their spawning grounds. 

 We do not know whether the ocean currents influence the movements of the schools 

 of salmon, and we are not acquainted with the capacity of the salmon for enduring 

 variations of temperature at sea. It appears from the best information we can obtain 

 that the schools of salmon have not been observed at a greater distance than a mile 

 and a half off-shore. The direction of their ocean movements has not been determined, 

 but Mr. Hirsch informs us that in approaching Karluk they come from all directions 

 and continue in compact schools until they are close to land, when the schools break 

 up. It is assumed as an established fact that the great body of the salmon come up 

 from the sea at a certain time of the year and ascend streams for the purpose of repro- 

 duction. We know that at the time when the salmon approach the Alaskan shores 

 certain species of small fishes constituting their food are abundant at sea near the 

 land. Among these are the capelin, herring, and lant. Salmon continue to feed upon 

 these species until they are ready to forsake the sea and enter the fresh waters. 



We could not learn that variations in temperature had much effect upon the daily 

 catch of salmon. The lowest temperature of the water noted at the surface in Karluk 

 Bay during our visit was 50°, and the highest 60°, the latter observed at noon, 

 August 12. The greatest variation in temperature observed in any one day occurred 

 August 13. At 7 a. m. the surface water was 50° and at noon it had reached 59°. 

 The ordinary variation from 7 in the morning to 6 in the evening was from 2J to 4£ 

 degrees. 



One of the sources of safety for the salmon at Karluk is the presence of beds of 

 the bull kelp, Macrocystis giganteus, in which the fish fiud shelter from the seiners. 



Karluk Bay is merely a shallow arm of Shellikoff Strait, limited on the southwest 

 by Cape Karluk, or Karluk Head, and on the northeast by high bluffs at the head of 

 Karluk Spit. The outlook from Karluk Bay is towards the northwest. The beach 

 descends very gradually from a low spit, and is composed of coarse gravel and large 

 granite bowlders. The bottom slopes down gradually until, at a distance of 100 fathoms 

 from the shore, the depth is several fathoms. There is very little good holdiDg-ground 

 for vessels. Some of the firms have fixed moorings at which their vessels ride out 



13 



