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Montana Field Guide

Montana Field Guides

Chinook Salmon - Oncorhynchus tshawytscha

Non-native Species

Global Rank: G5
State Rank: SNA

Agency Status


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General Description
One of two Pacific salmon species in Montana, the chinook salmon, was introduced into Fort Peck Reservoir during the 1980s in an effort to produce a trophy fishery. Like all Pacific salmon species, the chinook dies after spawning. It is doubtful that these fish will reproduce in Fort Peck, but due to their intense homing instinct they will return to where they were stocked when they are ready to spawn. They may then be captured and artificially propagated in the hatchery. While still experimental, chinooks of over 25 pounds have already been captured in Montana. Chinook, also known as "king salmon", are intense fish predators as adults.

Diagnostic Characteristics
Anal fin usually has 14 to 19 rays; its base is longer than base of dorsal fin. Has 26 or fewer gill rakers on first arch. Breeding males develop an elongated hooked snout and enlarged teeth. Females change little. Breeding fish of both sexes darken in color, males more than females. (FWP) Differs from other oncorhynchus by large size (to 45 kg), small black spots on both lobes of the caudal fin, black pigment along the base of the teeth, large number of pyloric caeca (>100), and variable flesh color (white to pink or red); fry and parr have large parr marks extending well below the lateral line (Healey 1991).

Species Range
Montana Range


Western Hemisphere Range


Observations in Montana Natural Heritage Program Database
Number of Observations: 46

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Smolts planted in tributary migration downstream in a lake.

A pelagic deep water species. Freshwater populations may spawn in rivers flowing into lake or on gravel shoals in the lake. The young may stay in the stream for a year or two before migrating downstream to the lake. There are no reproducing populations in Montana.

Food Habits
Adults highly piscivorous. Eat pelagic fishes such as cisco goldeye. Young in lake undoubtedly eat insects and plankton until large enough to eat fish.

Very limited spawning success in Great Lakes. Maintained by artificial propagation. Wholly self-sustaining freshwater populations exist only in New Zealand.

Reproductive Characteristics
No sign of natural reproduction in Montana. May run in spring, but invariably spawn during late summer-fall. Eggs hatch following spring. Adults die after spawning. Sexually mature in Lake Superior mostly at 2-3 yrs.

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Citation for data on this website:
Chinook Salmon — Oncorhynchus tshawytscha.  Montana Field Guide.  .  Retrieved on , from