124 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
appliances. In Monterey Bay, California, large numbers are taken with trolling hooks 
baited with small iisli, and, although the fish abstains from food after entering the 
fresh waters, it may often be lured with artificial or other baits. The chinook salmon 
begins to enter the California rivers in February, the Columbia in March, and the 
Alaskan rivers in May and June. The spawning season covers six months, extending 
from June to December, although the spawning period in any given basin is more 
limited, seldom exceeding one or two months. The highest accessible positions in the 
streams are sought by the spawning fish, which make rounded excavations in gravelly 
bottoms, in which the eggs are deposited. The vitality of the fish rapidly 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 Grairdner’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 distin- 
guish from the Atlantic salmon and from each other any specimens of quiunat salmon 
and steelhead that come to their notice, the following key* has been prepared to cover 
the principal differential characters, and illustrations of the three species are shown: 
I. Anal fin elongate, with 16 ray s ; gillrakers 9 + 14 ; hranchiostegals 15 to 19 ; pyloric cceca 
140 to 180; caudal fin considerably forked; average weight about 20 pounds, 
maximum 100 pounds Quinnat salmon. 
II. Anal fin short, with 9 to 12 rays; gillrakers 8 + 12: hranchiostegals 11; pyloric cceca 
less than 70. 
1. Teeth on vomer little developed, those on shaft few and deciduous; scales large, 
about 120 in lateral series ; pyloric caeca 65 ; caudal fin emarginate ; average weight 
15 pounds, maximum 40 pounds Atlantic salmon. 
2. Teeth on vomer well developed, those on shaft of bone numerous and persistent 
in a zigzag row or two alternating series; scales about 150 (130 to 180) in lateral 
series ; pyloric coeca 42 ; caudal fin squarely emarginate ; average weight 10 pounds, 
maximum 20 pounds Steelhead trout. 
“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; hranchiostegals, small bones supporting the lower margin of 
the gill cover; pyloric cceca, worm-like appendages of the lower end of the stomach; vomer, a bone 
in the front part of the roof of the mouth. 
