Pacific salmon occur from California north along the Pacific coast throughout the Pacific Ocean, Bering Sea and Arctic Ocean waters adjacent to Alaska. The five species (Chinook, Chum, Coho, Pink and Sockeye) are members of a large family of fish known as salmonidae, which are abundant throughout the temperate zones of the northern and southern hemispheres. Pacific salmon are a shorter lived species and much more prolific breeders than Atlantic salmon.
Chum salmon, also known as dog salmon, is the most widely distributed of the five species of Pacific salmon, and occurs from northern Kyushu, Japan to the Siberian arctic in Asia, and in North America from the Sacramento river, California northwards to the MacKenzie river in the Canadian arctic. Chum salmon spends most of its life in the ocean and returns to freshwater (anadromous) to spawn once and then dies (semelparous). Chum salmon are typically the last salmon to spawn, and most do not travel far upstream to spawn (usually at the mouth or lower reaches of rivers within 100 km of the ocean), albeit some do travel up to 2000 miles up the Yukon river. Although most Chum spawn in the autumn there are two distinct races with the earlier race known as summer chum salmon and the later race known as fall chum salmon. Each female lays 2-4,000 eggs. Juvenile chum salmon spend only a few days or weeks in freshwater before migrating to the ocean.