Coho Salmon - Oncorhynchus kisutch
California Overview
Coho salmon were once prevalent in coastal streams from Monterey Bay to Alaska. In the 1940s, California had an estimated 500,000 Coho salmon, a number which has plummeted to one percent or about 5,000 fish today.
The coho salmon is one of seven species of Pacific salmon belonging to the genus Oncorhynchus and one of five species found in California. In California, it is found in many of the short, coastal drainages from the Oregon border south to Monterey Bay. In the larger coastal drainages, it is found primarily in the lower sections. Coho salmon populations found in the drainages south of the San Francisco Bay are termed ‘southern coho salmon'. However, studies thus far have not demonstrated that these populations are genetically distinct from other, more northerly coho salmon populations.
For the most part, coho salmon's life cycle takes three years. They normally spend their first year in fresh water and their next two years in salt water prior to returning to spawn in their natal streams. Some males, called "jacks", return to spawn after only one season in the ocean. Spawning migrations begin after heavy, late autumn or winter rains encourage the returning adult to leave the ocean and move upstream. In many of the coastal streams south of San Francisco Bay, heavy river flows are needed to breach sand bars that have formed at the mouths of coastal streams before fish can migrate up.