ALASKA FISHERY AND FUR-SEAL INDUSTRIES, 1920. 131 



extent the early cohos turn into the Tanana it was impossible to 

 determine. 



In the lower two or three hmidred miles of the river the cohos 

 during the early days of August may maintain the bright silvery 

 coloration with which they enter from salt water, but soon a pinkish 

 tinge appears, which becomes intensified to a bright red before Ruby 

 is reached. At the same time the upper jaw of the male becomes 

 bluntly hooked over the lower jaw. producing the characteristic snub- 

 nosed appearance of this species on the s])awning grounds, and the 

 enlarged teeth of the males are soon in evidence. These changes in 

 appearance may have already occurred before entering the river in 

 the case of the latest individuals to enter. 



It is most unfortunate that the only name by which the coho salmon 

 is commonly known on the Yukon is " chinook," which is the special 

 name of the king salmon of the Columbia Kiver and is totally inap- 

 plicable to the coho. Xear the mouth of the Yukon, where the influ- 

 ence of the cannery has been felt, the coho is generally and properly 

 designated as the silver salmon, which is one of the two names by 

 which the s})ecies is known in other fishing centers of Alaska. Unfor- 

 tunately, as will later appear, elsewhere throughout the Yukon 

 the term '' silvei- salmon is generally but mistakenly applied to 

 an entirely different species. To avoid confusion, therefore, it is 

 suggested that this species be known on the Yukon as the coho, a 

 name by which it is generally known to the trade. 



KING SALMON. 



The king salmon appears at the river month shortly after the ice 

 has run out — in the last week of May or the early clays of June. The 

 numbers rapidly increase, the run culminates quickly, and then 

 almost as quickly declines. During the season of 1920 the first king 

 salmon was obtained on June 13. although nets had been set to test 

 the grounds for five days prior to that date. The rapidity with 

 which the run sets in is well shown by the records of the first few 

 days at the cannery. On June 15, 34 king salmon were obtained; 

 on June 16, 175; June 17, 1,G39; and on June 18, 5,228, this being 

 the next to the largest take on any day during the season. The 

 largest caj^ture of king salmon in any one day was 6,104 on June 21. 

 In no other day, except the two above mentioned, did the number 

 captured quite reach 4,000. The run may be said to have begun on 

 June 15 and to have culminated within the first week. It continued 

 for some 10 days thereafter at a high level, and then registered un- 

 mistakable decline. The average take at the cannery for the best 

 consecutive 16 days of the run was a little more than 3,000 fish 

 per day. 



The experience during the previous season, 1919, was very similar 

 as regards the beginning, culmination, and decline of the king salmon 

 run. The fish appeared (hiring the second week in June, ran most 

 abundantly during the following week, continued at a high level 

 for two weeks more, and then rapidly fell off. 



The average size of the 1920 king salmon was greater than that 

 cf 1919, as is shown by the average number required to make a case 

 in each of tlie two years. The average number in 1919 was 3.54 to 

 the case; while in 1920 it required but 3.03. The difference was even 



