• adipose fin is present
• adipose fin is un-pigmented (has a clear “window”)
• the length at the base of the anal fin is greater than the length at
• the base of the dorsal fin (anal fin is on an angle, slanted back)
• parr marks are present
• parr marks are dark coloured over lighter coloured side of fish (dark on light background)
• parr marks are oval shaped and the height is greater than the vertical diameter of the eye
• spaces between the parr marks is less than the width of the parr marks themselves
• caudal (tail), dorsal, anal and pectoral fins may have pale orange colouring

Known distribution in Yukon: Yukon River mainstem and tributaries.

Other notable comments and clues:

• One of the most distinguishing features of the juvenile chinook is that the adipose fin has a clear center, or “window”.
• Chinook can be easily mistaken or confused with juvenile coho.
• When trying to ID in the field, generally speaking the chinook and coho have similar shaped parr marks (the parr mark height is greater than the vertical diameter or the eye) but the coho has a uniformly pigmented adipose fin and a more dramatically sickle-shaped anal fin.
• Chinook may have a white-tipped dorsal fin and white on the leading edge of the anal fin – look for a black line following the white tips, this is a coho trait.
• Sometimes the only way to tell chinook from coho is by counting the number of pyloric ceacae, and this requires that samplers sacrifice fish (it’s mortal to fish).