The English name "chum salmon" comes from the Chinook Jargon term tsəm, meaning "spotted" or "marked"; while keta in the scientific name comes from Russian, which in turn comes from the Evenki language of Eastern Siberia.

Chum have an ocean coloration of silvery blue green with some indistinct spotting in a darker shade, and a rather paler belly.

Spawning males typically grow an elongated snout or kype, their lower fins become tipped with white and they have enlarged teeth.

[citation needed] Adult chum salmon usually weigh from 4.4 to 10.0 kg (9.7 to 22.0 lb) with an average length of 60.0 cm (23.6 in).

The all-tackle world record for chum recognized by the IGFA is 35 lb (15.88 kg) and 112.0 cm (44.1 in) caught by Todd Johansson on July 11, 1995 at Edye Pass (a channel between Prescott and Porcher Islands in the Hecate Strait) in the North Coast region of British Columbia;[8] while the all-tackle length world record is 71.0 cm (28.0 in) caught by Vicki D. Martin on October 20, 2021 at Wynoochee River in Washington.

They utilize the lower tributaries of the watershed, tend to build nests called redds, really little more than protected depressions in the gravel, in shallow edges of the watercourse and at the tail end of deep pools.

Chum are found all around the North Pacific, off the coasts of Japan, Korea, the Russian Far East, British Columbia in Canada, and from Alaska to California in the United States.

[12] In fall 2017 a half dozen chum salmon were counted in Lagunitas Creek about 25 miles (40 km) north of San Francisco, California.

[13] In the open ocean, chum salmon stay fairly high on the water column, rarely diving below 50 m (160 ft).