The body of the chum salmon is deeper than most salmonid species. In common with other species found in the Pacific, the anal fin has 12 to 20 rays, compared with a maximum of 12 in European species. Chum have an ocean coloration of silvery blue green with some indistinct spotting in a darker shade, and a rather paler belly. When they move into fresh water the color changes to dark olive green and the belly color deepens. When adults are near spawning, they have purple blotchy streaks near the caudal peduncle, darker towards the tail. Spawning males typically grow an elongated snout or kype, their lower fins become tipped with white and they have enlarged teeth. Some researchers speculate these characteristics are used to compete for mates.