http://www.sciencedaily.com/releases/2008/01/080129210349.htm

Salmon Population Declines In California,
West Coast

ScienceDaily (Feb. 4, 2008) — California Central Valley fall Chinook salmon stocks appear to be undergoing a significant decline, according to Pacific Fishery Management Council Director Donald McIsaac.  Although the numbers are currently being verified by the Council, Dr. McIsaac said that if the low abundance is confirmed, all marine and freshwater fisheries impacting this important salmon stock may be affected.

The low returns are particularly distressing since this stock has consistently been the healthy “work horse” for salmon fisheries off California and most of Oregon.

Not long ago, the Council’s Salmon Technical Team (STT) met to tabulate salmon returns and catches. Two areas of bad news emerged. First, in 2007 the adult spawning escapement for Sacramento River fall Chinook failed to meet the escapement goal (122,000180,000 adults) for the first time in 15 years.  Sacramento River fall Chinook are the largest component of Central Valley Chinook.  (The escapement goal, or conservation objective, is the optimal number of adult fish returning to spawn in order to maximize the production of the stock).

Second, the count of “jacks” in the Central Valley fall Chinook return this past fall was a record low.  Only 2,000 jacks returned, compared to a longterm average of about 40,000 and the previous record low of 10,000. Jacks are immature fish that return to the rivers at age two (unlike adult fish, which return at age three or four). Their numbers are used to forecast future returns.

This suggests that 2008 abundance will probably also be weak.  Scientists now question whether returns in 2008 could meet the conservation objective even without any commercial or recreational salmon fishing where these fish are found.  If returns do not meet the conservation objective, an emergency rule from National Marine Fisheries Service may be required to allow any fisheries.

Reason for decline

The reason for the decline is unclear. Both hatchery and naturally produced fish have been negatively affected, and returns of coastal stocks in Oregon, in the Columbia River, and in British Columbia were all low in 2007. The decline seems to be a coastwide phenomenon, probably related to ocean conditions.

Economic implications

The implications of a precipitous decline could be substantial for both commercial and recreational fisheries coastwide. In 2006, a similar decline in Klamath stocks led to major cutbacks in salmon fishing opportunities. Sacramento River salmon have a greater range than Klamath River stocks, and are caught in California, Oregon, Washington, and even British Columbia. They are considered the “driver” of commercial fisheries in Oregon and California.