SALMON AND TROUT IN ALASKA. 59 



the larger size of examples noted in Wallowa and Alturas lakes and 

 the Fraser River. 



The dog-salmon young, cited above, vary from a little over 40 mm. 

 to 120 mm.; the humpback show approximately the same figures. 

 These are unquestionably of the fry that reached salt water in March 

 and April just previous. The catches date about three months later. 

 This indicates an increase of about 100 per cent in that length of 

 time, or about twice the rate of growth of the sockeyes that remain 

 in fresh water. In other words, the species (or individuals) that reach 

 salt water as fry make about the same growth in the first three 

 months that the lake residents (sockeyes) make in twelve. The com- 

 parison of fall catches of cohos and sockeyes in the lakes shows the 

 former to exceed the latter greatly in size, but this is only a natural 

 result of the coho's greater size from the fry stage to the adult. In 

 the case of the humpback, however, the fry is scarcely larger than 

 that of the sockeye, and the adult somewhat smaller. Its more 

 rapid growth can be attributed onl}^ to the abundance of food in 

 salt water and the nature of the fish. The socke3^e young which 

 were taken in salt water must be yearlings. Owing to the lateness 

 of the migration of that species it is impossible for them to have 

 attained such size in the time since they could hav6 reached salt 

 water as fr}^ of that same season. 



It will be seen that in general the four species of salmon are closely 

 associated in sea habit. While small they remain much of the time 

 close inshore, to some extent feeding on the insects that fall on the 

 water or are carried down by the streams. The greater part of the 

 food, however, is the various crustacean forms, though the small fry 

 of marine species make up no small part, particularly of the coho's 

 food. With increasing age the salmon doubtless move into deeper 

 water. If the habit of preying on small fishes continues and grows 

 \\'ith the increase of size, it would seem that the 3'oung salmon would 

 be remarked in pursuit of the schools of young herring, sand launces, 

 and such forms that abound in the bays and coast waters. No note 

 of this has been recorded. Occasional catches of slightly larger fish 

 are made from time to time, possibl}^ fish of the second year. Such 

 cohos are well known in Puget Sound, and a run of some small sal- 

 mon was observed in Naha Bay during the winter of 1896-97. But 

 unless such fish in large numbers approached the surface of some 

 small body of water near a settlement, they would scarcely attract 

 attention though the channels were teeming with them. 



The salt-water habits of young trout and charrs are entirely 

 unknown. 



RETURN OF ADULTS TO FRESH WATER. 



From the 3'earling stage to tlie adult little is known of any of the 

 salmons, and nothing of the sockeye. There are reports of grown 

 fish of that species taken in the winter in various places, as in the 



