SALMON AND SALMON EIVERS OF ALASKA. 
179 
KARLUK LAKE. 
(Plates Lxiii-Lxvii aacl Lxxxn.) 
As alreadj^ stated Karluk Eiver rises in Karluk Lake. This lake is about 8 miles 
long and has an average width of probably 2 miles. Its general direction is north 
and south. The maximum depth of the lake is unknown. I tried a sounding, with 27 
fathoms of line, about 500 yards from the shore, and found no bottom. The water 
is blue. Along many portions of the shore the lake is very shoal for a considerable 
distance from land. In other places there is deep water close to the margin. The 
shores are composed of bowlders of various sizes, consisting of granite and other 
rocks. Sand beaches are entirely absent as far as our observations extended. No 
aquatic plants were observed around the margin of the lake. The shores are covered 
with a greasy deposit, doubtless composed of decayed animal matter, and in the very 
shoal water in many places there is -a dense growth of dirty looking confervm. There 
is a luxuriant growth of grass throughout the basin of Karluk Lake, extending often 
to the tops of the mountains. Willows exist here as good-sized shrubs, and in some 
places as small trees. The low grounds in many portions of the basin are covered 
with cottonwood trees, some of which attain to a height of 60 feet and a trunk diame- 
ter of 18 inches. 
Conspicuous among the fruit-bearing plants is a species of elderberry, Samhucus, 
bearing brilliant red berries, which form part of the food of the bear. In the cotton- 
woods are numerous families of the American eagle, and the shores of the lake har- 
bor many species of birds, among which are gulls and terns, plovers, and magpies. 
Ducks and loous are found on the lake. At about the middle of its length Karluk 
Lake divides into two arms ; one, extending to the eastward, is referred to in this 
report and on Mr. Booth’s charts as the east arm; the other follows the general direc- 
tion of the lake, and is very much longer than the east arm. Three small islands are 
situated near the junction of the east and west arms. Karluk Lake receives the waters 
of numerous small streams, in which salmon and trout are found whenever they are 
not prevented from entering them by the abruptness of the ascent. Each of the arms 
of Karluk Lake is connected by a short, rapid, and crooked river with smaller tributary 
lakes. The lake tributary to tlie east arm is about four-fifths of a mile in length, and 
the one connecting with the west arm is about IJ miles long. In the small tributaries 
of Karluk Lake the rivers connecting its arms with their tributary lakes and at 
various places around the shores of the i^riucipal lake — particularly at its southern 
end, between the mouths of rivbrs — we found nests of the red salmon. Karluk Lake 
is surrounded on all sides, except the north, by low mountains, some of the elevations 
of which exceed 2,000 feet. 
During our stay, from the 18th to the 2lst of August, the lowest temperature of 
the water of the lake was 48^-°; this was at 4.30 a. m. The highest recorded temper- 
ature of the water was 55° at 9^30 a. m. August 20. The highest temperature of the 
air was observed at 10.20 a. m. August 20, when it was 77°, and the lowest temper- 
ature during our visit occurred at 4.30 a. m. August 21, when it dropped to 30^°, 
ice being formed at our camp. Although the air was intensely cold, the surface 
water of the lake registered 48J°. The small rivers connecting Karluk Lake with its 
tributary lakes contain no obstructions to the passage of the salmon, These lakes 
