32 SALMON AND TROUT IN ALASKA. 



They contained insects, larvae, and crustaceans. The remainder were 

 recently out of the fry stage, and only a few had begun to eat. This 

 indicates that some of the young remained some time longer in the 

 pools than they would have done in a stream of different character. 

 Their late development is doubtless due to the cold spring water. 

 Nets set across one of the principal spawning creeks on July 16 and 

 27 took very few fry. 



After some days, perhaps when growing necessity for food demands 

 activity, sockeye young, as fry or small fingerlings, drop down the 

 stream into the lake or maybe the sea. During the season of observa- 

 tion on the Naha none was ever seen in the stream below the lakes, 

 though cohos in abundance were resident there throughout the summer. 

 Nor were any ever seen b}^ the writer about the margins of any Alas- 

 kan lakes except in the one instance mentioned below. Sockeyes 

 apparently are never resident in the streams and never found in them 

 except during the migratory movement. 



Wliile adequate observations are lacking, it is probable that the 

 fr}^ travel in schools. In the Karluk they were observed by Rutter 

 to school while in the sloughs, though they have nowhere been seen 

 to migrate in schools. In the lakes they remain during daylight in 

 comparatively deep water. Rutter notes that they were at no time 

 seen in abundance about the shores of Karluk Lake; Babcock states 

 that they were not seen in Seton Lake after May. In the Naha lakes 

 they were seen but once, June 11, a small school in Heckman Lake 

 near the outlet, and a few in Jordan Lake in company with numerous 

 cohos. They were taken in Alturas Lake outlet by Evermann on 

 July 20 with fingerlings of the same species. Later in the season 

 young sockeyes were obtained in Alturas Lake only by sinking the 

 seine to the bottom in water of considerable depth, 15 to 60 feet. ^ In 

 Yes Lake in 1905 they were taken by surface hauls of a 130-foot seine 

 after dark in the latter part of August and September, and the same 

 means were used successfully in the Naha lakes later in that season. 



FOOD AND FEEDING. 



In the lakes and in all waters where such food is available, young 

 sockeyes subsist largely upon small Crustacea and associated forms, 

 most of which have a diurnal movement to and from the surface, 

 varying with the light. In the evening they rise to near the surface, 

 and, with the coming of daylight, or shortly preceding day, retire to 

 greater depths." In 1905 from August to November a number of 

 tows with fine nets in Yes Lake and the Naha lakes showed that 

 crustaceans are ordinarily absent from the surface during daylight. 



a The diurnal movement of plankton Crustacea, by Chancey Juday. Transactions 

 Wisconsin Academy of Sciences, vol. xiv, 1904, p. 534-568. 



