SALMON AND TROUT TN ALASKA. 75 



the stream proper seems to vary with locaHty, species, and time of 

 year. In some cases it is perhaps necessary that some time be so 

 spent to inure the fish to the fresh water. Their natural timidity in 

 approaching shallows has been mentioned above. This may be due 

 to the exposure entailed or to recognized dangers in swift water. 

 Adult sockeyes released at the foot of Seton Lake passed through the 

 17 or 18 miles of that body of water to its upper extremity in from 

 eight and one-half to about eleven hours, presumably in daylight. 



INTERVAL BETWEEN ARRIVAL AND SPAWNING. 



The early arrivals of salmon spend some time in the region of the 

 spawning beds before depositing any spawn. In the Naha the first 

 sockeyes reach the lakes in June, but none spawn earlier than about 

 the middle of August — after a lake residence of about six weeks. In 

 the Karluk in 1903 the first sockeyes entered the lake about the 

 middle of June ; they continued to arrive in numbers until the latter 

 part of July. They spawned during August. The first arrivals, as 

 in the Naha, thus spent about six weeks in the lake and all remained 

 at least four weeks before spawning. In the Fraser basin in 1905 

 the first fish reached Seton Lake the latter part of July, the run 

 continuing until the latter part of September. The first eggs were 

 spawned the first week of September, and spawning continued until 

 late in October. This was approximately the same length of resi- 

 dence before spawning as in the Naha and the Karluk. 



During the residence in the lakes it is improbable that the fish 

 occupy the greater depths, since it has been shown that these are not 

 suitable for fish life. In the evenings salmon may often be seen in 

 numbers "finning," i. e., swimming leisurely at the surface in such 

 manner as to expose the dorsal fin. The sockeye seldom jumps in 

 lakes until about to approach the spawning bed, when there may be 

 a slight demonstration of that habit. Ordinarily a lake may be filled 

 with adult fish and no evidence of their presence noted by the observer. 



The early king salmon also reach the beds some time before spawn- 

 ing. They reach the McCloud late in June or early in July, but do 

 not spawn until the middle of August. In the Idaho investigation it 

 was found that they reached the upper Salmon Valley the last half 

 of July, the spawning occurring approximately a month later. All 

 sockeyes had entered Alturas Lake before July 20 and spawned from 

 the 23d until into September, the height of the season being about 

 the last of August. The fish seem to have spent at least a month in 

 the lake. 



The late-running species — coho, humpback, and dog — arrive only a 

 short time before maturity. 



