Page:Popular Science Monthly Volume 64.djvu/176

172 rivers as the Skaguay River, or they may be little brooks, in any case not frequented by the king salmon, and having no lake in the course, hence not fit for the red salmon. Their runs are confined to the ignoble species, which ascend for a short distance only. In the larger streams to the northward as Skaguay River and Dyea River, the dog salmon predominates. Southward as in Fish Creek, at Ketchikan and Anan Creek, the humpback salmon predominates, although the humpback is equally common in the red salmon streams. Some of these streams of the third class as Fish Creek flow through lakes. Presumably these lack fit spawning grounds.

The question as to what constitutes the mouth of the river is one of some importance in Alaska. The tides run very high, often twentyfive feet or more, the high tide extending far up the estuaries, which at low tide may be occupied by fresh water. The Naha Stream at Loring flows through a series of lakes, the lowermost of which (Roosevelt Lagoon) lies close to the estuary of the stream, the water flowing from the lake over a considerable waterfall at low water. At high tide this cascade is reversed, the salt water passes by an overfall into the lake, which is thus converted into a brackish lagoon. It is a well separated lake at low water, part of the sea at high water.