Chinook and Coho Smolts Identification

Chinook (Oncorhynchus tshawytscha) smolt or juvenile has black gum, and the tip of jaw is pointy and black. The spaces between parr marks are narrower than the width of the marks. Chinook has larger otoliths than other species.

Coho (Oncorhynchus kisutch) smolt of juvenile has white gum, and the tip of jaw is round and white. The spaces between parr marks are wider than the width of the marks.

Both have strongly forked tail than Steelhead or Atlantic salmon.

pictures - courtesy of northcoastweb.com