134 U. S. BUREAU OF FISHERIES. 



Inspection of the above table shows the slowest rate of travel in 

 the first himdred miles of the river above its month. From the en- 

 trance of the South Mouth to Pilot Station is approximately 130 

 miles, but it was five davs after the run began in the mouth of the 

 river before the first king salmon appeared at Pilot Station, indi- 

 cating a rate of about 30 miles per day. Between Pilot Station and 

 Tanana, on the other hand, the rate of travel was slightly more than 

 80 miles per day. This discrepancy is probably due to the habit of 

 playing back and forth in brackish water, on entering the river 

 mouth, before beginning their serious ascent of the river. It is well 

 known to tlie fishermen at the mouth of the river that salmon enter 

 the gill nets as numerously from the upstream as from the down- 

 stream side. They pass back and forth on the tides, lingering within 

 the fishing district, thus giving the nets many more opportunities to 

 capture them than would be the case if they pursued a direct course 

 on entering the stream. 



Three records below Tanana, those of the camp 51 miles below 

 Kaltag, Kaltag itself, and Koyukuk, do not align themselves with 

 the remainder of the series. At the aA^erage rate of travel king 

 salmon should have reached Kaltag by the 24th instead of the 28th 

 and Koyukuk by the 25th instead of the 29th. In botli of tliese 

 localities the capture of king salmon was considered of little relative 

 importance, and the records are doubtless defective. 



Above Tanana the current of the river increases materially, rapids 

 are encountered, and the intricate channels of the Yukon Flats are 

 to be threaded. It is not surprising to find that the rate of travel in 

 tlie upper portion of the river becomes reduced. Not only are the 

 difficulties of ascent increased but the potential store of energy in 

 the fish approaches exhaustion. When they enter the mouth of the 

 river they are the richest in oil of any salmon known, but by the 

 time they reach Dawson their flesh is comparatively dry and flavor- 

 less, the oil having been expended to supply the energy needed in 

 ascending 1,500 miles against the current and in carrying forward 

 at the same time the sexual changes which precede the act of spawn- 

 ing. The average rate of travel from Tanana to Dawson was 

 slightly less than 45 miles per day, while from Pilot Station to 

 Dawson, involving practically the entire length of the river below 

 Dawson, the average rate was 57 miles per day. 



No record of any other river approaclies this in completeness nor 

 in the high rate of travel indicated. The unexampled speed with 

 which salmon ascend the Yukon is doubtless associated with the 

 great distances to be traversed before reaching their upper spaAvning 

 areas, taken in connection with the shortness of the northern summer. 



Inasmuch as the investigators were compelled to restrict their 

 attention to the main river, they are unable to designate the prin- 

 cipal spawning areas of the king salmon. Limited numbers of kings 

 are reported to turn aside into all the principal tributaries of the 

 lower and middle sections of the river, but it is believed that a rela- 

 tively large proportion of the run passes beyond the month of the 

 Porcupine into tlie upper portion of the basin. 



CHUM OR DOG SALIMON. 



Although the king salmon is an important source of food to the 

 natives and the white population, it is far surpassed in value by the 



