SALMON AND TROUT TN ALASKA. 57 



Karluk (p. 52) ; some had eaten almost exclusively large copepods, 

 others ostracods, and yet others a peculiar CaprellaAike form. 



Four specimens from Isanotski Straits, July 15, 1894, show no pecul- 

 iar features. 



At Sucia Island, May 6, 1894, 3 humpbacks and 1 dog salmon were 

 taken, the former 47 mm. and the latter 54; food, Crustacea. 



At Metlakatla, July 10, 1903, 2 humpbacks w^ere taken, 64 mm. 

 in length. One was empty, the other contained flies. 



Single specimens of humpback fingerling are recorded from Kodiak, 

 August 14, 1888, and Unalaska, July 23 of the same year. The first, 

 a female 113 mm. long, contained small fry and a few flies; the last, 

 a male slightly larger, crustaceans. 



CONCLUSIONS FROM AVAILABLE DATA. 



From the above notes it may be concluded that many young sock- 

 eyes, after reaching saltwater as yearlings early in the spring, remain, 

 in company with other young salmon, for a few months about the 

 shores near the mouths of the streams from which they are derived ; 

 that during this time they feed principally upon the small crusta- 

 ceans which are found from the surface to an unknown depth and, 

 like the crustacean forms found in the lakes, have a diurnal move- 

 ment from and to the surface. In tows made by the Albatross in 

 the open ocean it has been foimd that many of these forms tend to be 

 most abundant at the surface about dark, again decreasing in number 

 within an hour or so. Whether the period repeats again at daylight 

 was not tested. Surface tows in daylight made in Yes Bay and Behm 

 Canal during July, August, and September, 1905, showed an almost 

 entire absence of food material. At the same time it was found at 

 depths of 20 to 75 fathoms and greater, the deeper the more abundant. 

 It is known that this pelagic life is ultiinately dependent upon the 

 shore for food supply. The open sea far distant from land contains 

 little life, unless it be conveyed by currents originating near land. The 

 narrow and deep channels of Southeast Alaska furnish a superior 

 environment for plankton life ; to the wholly free-swimming forms, 

 such as copepods, ostracods, etc., there is add'ed the innumerable 

 progeny of the littoral forms, such as crabs, worms, mollusks, and 

 shore-spawning fishes. 



ABUNDANCE OF FOOD. 



As a test of the abundance of this salmon food material, during the 

 summer of 1905 numerous hauls were made throughout Yes Bay and 

 into Behm Canal. Yes Bay is a long, narrow inlet less than one-half 

 mile in width and over 4 miles in length, the depth varying from 50 

 feet at the head to over 50 fathoms at the mouth. It receives sev- 

 eral small creeks at the head and the main stream from Yes Lake, 

 about midway between the two extremities. During the summer 



