The chum salmon (Oncorhynchus keta) is one of the five species of Pacific salmon, possessing the broadest natural geographical distribution across the North Pacific Ocean. They range from the Sacramento River in California north to the Arctic coast of Alaska, and west to the Korean peninsula and the Sea of Japan. As an anadromous fish, they hatch in freshwater, migrate to the ocean to feed and mature, and then return to their natal streams to spawn.
Physical Characteristics and Identification
The appearance of the chum salmon changes dramatically as it transitions from the ocean to its spawning grounds. At sea, the fish has a streamlined, metallic greenish-blue back with a silvery sheen, typically lacking the large black spots found on other salmon species. Chum salmon are one of the largest Pacific salmon species, second only to the Chinook salmon in size.
The average chum salmon weighs between 8 and 15 pounds and measures 24 to 28 inches in length, though individuals can exceed 30 pounds. Moving into freshwater to spawn, their body color undergoes a pronounced transformation, developing a striking pattern of vertical bars. This coloration is a mix of bold red, purple, and black stripes, often leading to the common name “calico salmon.”
Spawning males develop a highly pronounced hooked snout, known as a kype, lined with large, canine-like teeth used for fighting other males for mating rights. Females also change color, displaying a dark horizontal band along their lateral line, but they do not develop the large fangs or kype.
Life Cycle and Spawning Migration
The life cycle begins when chum salmon hatch from eggs buried in a gravel nest (redd) in a freshwater stream. After emerging as fry, they spend a remarkably short period in their natal stream compared to most other Pacific salmon species. They migrate downstream to the estuary and ocean within days or a few weeks of emerging.
The juveniles spend several months in nearshore habitats and estuaries before dispersing into the open North Pacific Ocean to feed and grow. Chum salmon typically spend three to six years at sea before reaching sexual maturity, often returning at three to four years of age. During this time, they feed on copepods, fish, squid, and mollusks.
When mature, the adult salmon return to their birthplace to reproduce, a process known as anadromy. Spawning generally occurs in the lower reaches of rivers and streams, often within 60 miles of the ocean. Some populations, such as those in the Yukon River, undertake incredibly long migrations, traveling over 2,000 miles upstream to reach spawning grounds in interior Canada. All chum salmon die after spawning, providing nutrients back into the freshwater ecosystem.
Common Names and Economic Significance
The chum salmon is known by several common names, reflecting specific characteristics or commercial use. The name “Dog Salmon” refers directly to the large, canine-like teeth that spawning males develop. These teeth are used during fighting between males to establish dominance and secure mating opportunities.
The commercial market often refers to the species as “Keta Salmon,” derived from its scientific name, Oncorhynchus keta. This name is frequently used in marketing to distinguish it from species like Chinook or Sockeye, which are perceived as having higher oil content and a more desirable flavor profile. The meat of the chum salmon is paler than other species, ranging from pink to red, and has a moderate oil content.
Despite sometimes being considered less valuable than other salmon in North America, chum salmon are highly valued for their roe, a popular form of caviar, particularly in Asian markets. Chum salmon are an abundant species, making them a traditional source of food for indigenous communities, often dried for winter sustenance. Commercially, the fish is primarily used for canning, smoking, and processed fish products.