Oncorhynchus keta, commonly known as chum salmon, is a species of anadromous Pacific salmon in the family Salmonidae. It is native to the North Pacific Ocean and adjacent river systems, ranging from the coasts of Japan, Korea, and the Russian Far East across Alaska and western Canada to the Pacific Northwest of the United States. The genus name Oncorhynchus derives from Greek meaning “hooked snout,” referring to the pronounced hooked jaw (kype) that males develop during spawning while the species epithet keta comes from a word used in Siberian or Kamchatkan languages for this salmon species. The common name “chum” likely derives from a Chinook Jargon term for this fish. Like other Pacific salmon, it hatches in freshwater, migrates to the ocean to mature, and returns to its natal rivers to spawn.

Historically, chum salmon has been one of the most important subsistence and trade fish for Indigenous peoples of the North Pacific Rim, including Inuit, Yupik, Tlingit, Haida, Coast Salish, Ainu, and numerous Siberian groups. In modern contexts, it remains commercially significant, especially for its roe and for processed salmon products. Traditionally, it was extensively dried, smoked, or fermented in Arctic and subarctic cultures to provide winter sustenance. Its relatively lower fat content compared to species like sockeye or king salmon made it particularly suitable for drying. In modern global markets, chum salmon is consumed fresh, frozen, canned, and smoked, and is especially valued for its roe, marketed as salmon caviar (ikura in Japanese cuisine). The flesh is pale to medium pink, leaner than other Pacific salmon, and commonly used in fillets, jerky, soups, and stews.

Significant bioactive compounds present in Oncorhynchus keta include the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are associated with cardiovascular and anti-inflammatory benefits; astaxanthin, a carotenoid responsible for the pink coloration of the flesh and known for antioxidant properties; vitamin D (cholecalciferol), important for calcium metabolism and immune function; and selenium, an essential trace mineral with antioxidant roles. EPA and DHA are heat stable to typical cooking temperatures but susceptible to oxidation if overheated; astaxanthin is relatively heat stable but can degrade with prolonged high heat. These compounds contribute both to the nutritional value and to the ethnobiological importance of chum salmon across North Pacific cultures.