apidly decreases after
spawning, their bodies become mutilated and diseased, and in a short
time they die.

The steelhead (_Salmo gairdneri_) also known by the names of salmon
trout, winter salmon, and Gairdner's trout, closely resembles the
Atlantic salmon in size, form, and habits. It is found from southern
California to Alaska, and enters the coast rivers in large numbers.
Its flesh is light-colored, but is of excellent flavor, being not
inferior to the eastern salmon. It is caught in large quantities with
gill nets and traps, for canning and use in a fresh condition. As
a game fish the steelhead enjoys a high reputation in the Pacific
States. Its principal run in the rivers is during the fall and winter
months, when it ascends the streams long distances, spawning in late
winter or early spring.

In order that anglers, fishermen, fish-dealers, and others may be
able to distinguish from the Atlantic salmon and from each other
any specimens of quinnat salmon and steelhead that come to their
notice, the following key [4] has been prepared to cover the principal
differential characters, and illustrations of the three species are
shown:

[Footnote 4: The parts referred to in the key may be defined
as follows: Anal fin, the single fin on the median line of
the body, between the vent and the tail; gillrakers, bony
protuberances on the concave side of the bones supporting
the gills; branchiostegals, small bones supporting the
lower margin of the gill cover; pyloric coeca, worm-like
appendages of the lower end of the stomach; vomer, a bone in
the front part of the roof of the mouth.]

I. Anal fin elongate, with 16 rays; gillrakers 9 + 14; branchiostegals
15 to 19; pyloric coeca 140 to 180; caudal fin considerably
forked; average weight about 20 pounds, maximum 100 pounds.
Quinnat salmon.

[Illustration: Chinook or quinnat salmon (_Oncorhynchus
tschawytscha_)]

II. Anal fin short, with 9 to 12 rays; gillrakers 8 + 12:
branchiostegals 11; pyloric coeca less than 70.

1. Teeth on vomer little developed, those on shaft few and
deciduous; scales large, about 120 in lateral series;
pyloric coeca 65; caudal fin emarginate; average weight
15 pounds, maximum 40 pounds.
Atlantic salmon.

[Illustration: Atlantic salmon (_Salmo salar_)]

2. Teeth on vomer well developed, those on shaft of bone
numerous and persistent in a zigzag