SALMON OF THE YUKON RIVER. 



319 



salmon, and the same is true of the chum or dog salmon of the Yukon, which excels in 

 richness and amount of oil the chum salmon from all other rivers in as great a degree as 

 that which distinguishes the Yukon kings from other king salmon. 



As regards the rate at which they ascend the river, we have more reliable and complete 

 data for the Yukon than have been secured in any other stream. Records were obtained of 

 their first appearance at a large number of localities. Some of these were ascertained by 

 means of wireless messages sent during the early days of the run, before the dates of the first 

 captures should be forgotten. Many others were obtained during our ascent of the river in 

 early August, when all fishing camps were visited and records were inspected concerning 

 the run of the summer. In a number of instances complete written records were available, 

 which gave not only the date on which the first captures were made, but the numbers of 

 fish taken on each day of the season. While we recognize that the capture of the first 

 salmon of the season at different points along the river may vary within a few days in 

 relation to the beginning of the run, we are convinced from an examination of our data 

 that this source of error is not serious and that reliable conclusions concerning rate of 

 travel can be drawn from the table (1) presented below. Whenever two or more records 

 were obtained from different fishermen in the same locality the earliest has been selected. 



It will be noted that the lowest rates of travel apparently occur in the lower course of 

 the river. But the results are here obscured by the known fact that salmon, on entering 

 the tidal area of a stream, move back and forth with the tides for an undetermined period, 

 before seriously undertaking the ascent of the river. The influence of this factor, how- 

 ever, will not alone suffice to explain the constant increase in rate of travel as far up the 

 river as Tanana, where it had reached an average for the entire river below this point of 

 62 miles per day over a period of 13 days. 



Above Tanana, the rate again decreases, possibly due to the retarding influence of the 

 Rampart Rapids together with the general increase in current found in the upper portion of 

 the river, but the rate exhibits an unmistakable tendency again to augment as Dawson is 

 approached. The first king salmon to reach Dawson in the middle of July, 1920, had 

 been traveling against a consistently rapid current for 29 days, at the rate of 52 miles per 

 day, and during this period, as always within the river, had taken no food. 



Table i. — Dates of Capture of First King Salmon at a Series of Localities Along the Yukon 



River During Season of 1920. 



Locality 



South mouth of river 



Run begins south mouth. . . . 



Pilot Station 



Marshall 



Russian Mission 



Paimiut 



Holy Cross 



Halls Rapids, above Anvic. 

 Camp 51 miles below Kaltac . 



Kaltag 



Koyukuk 



Approxi- 

 | mate 

 [ number 

 I of miles 

 t traveled. 



June u 



June 15 

 June 20 



..do 



June ;i 

 June 22 

 June 23 

 June 24 

 June 27 

 June 2S 

 June 29 



107 

 144 

 204 

 259 



379 

 346 

 440 

 491 



555 



Miles 



traveled 

 per day. 



Locality. 



Whiskey C reek .above Louden 



Ruby 



Tanana 



Fish Creek, above Rampart 



Rapids 



Circle 



Charlie Creek 



Eagle 



De Wolf's fish camp 



Dawson 



Approxi- 



\ mate 

 Date. 1 number 

 of miles 

 traveled. 



June 27 



...do 



June 2S 



July 3 

 July 11 

 July 12 

 July 13 

 July 14 

 ..do.... 



Miles 

 traveled 

 per day. 



62a 



659 

 S04 



851 

 1. 227 

 1,311 

 1.402 

 1.478 

 1,504 



50 

 51 

 52 



The season of 1920 was notably late in Alaska; the break-up occurred in the Yukon 

 fully a week later than usual, and the salmon were equally delayed in entering. As 

 shown by the above table, the first king salmon taken in the delta was captured June 13. 



