In a recent interview for the Sacramento Bee, Stafford Lehr, fisheries branch chief for the California Department of Fish and Game, stated that the Central Valley fall-run of Chinook salmon is expected to be “very healthy.” The fishing season for Central Valley rivers opened on July 16th for recreational anglers. State and federal officials estimate more than 800,000 adult Central Valley Chinook salmon will make the spawning run this year, a drastic improvement from the historic low of approximately 40,000 salmon in 2009.
Mr. Lehr attributed the increased salmon numbers to improved ocean conditions, stating: “the ocean conditions improved significantly, which increased food availability and adult survival out in the ocean.” When asked what caused the drastic decline in the fall-run Chinook salmon, starting in 2007, Mr. Lehr responded: “Among federal and state fishery managers, there’s consensus that it was ocean conditions—very poor ocean conditions—that did not produce enough food for adult salmon.” He believed that the recent decline in the Central Valley Chinook salmon has been “primarily linked to ocean conditions.”
Poor ocean conditions were identified as “major factors influencing west coast salmon populations” in the 5-year reviews for the threatened Central Valley spring-run and the endangered Sacramento River winter-run, prepared by the National Marine Fisheries Service and released on August 15, 2011. (Spring-run 5-year Review, at p. 25.) The 5-year review for the spring-run stated:
Ocean conditions, such as sea-surface temperatures and upwelling are major factors influencing west coast salmon populations (Wells et al. 2008), including those from the Central Valley (Lindley et al. 2009). As previously discussed, Lindley et al. (2009) found that poor ocean conditions in the spring of 2005 and 2006 led to poor growth and survival of Central Valley juvenile salmon entering the ocean in those years. Upwelling off the California coast was stronger than average in the spring of 2007 and 2008 indicating good ocean conditions for Central Valley spring-run Chinook salmon smolts entering the ocean during those years (Lindley et al. 2009). Since the unusual ocean conditions in 2006, more typical patterns of upwelling and sea-surface temperatures have returned (Williams et al. 2011). The poor ocean conditions in recent years clearly had adverse impacts on the CV spring-run Chinook ESU as discussed previously.
(Spring-run 5-year Review, at pp. 25-26.) Similarly, the 5-year review for the endangered winter-run stated:
The last five years has been a period of widespread decline in all Central Valley Chinook salmon stocks including the SR winter-run Chinook salmon ESU. An analysis by Lindley et al. (2009) found that unusual oceanic conditions led to poor growth and survival for juvenile salmon produced in the Central Valley during the spring of 2005 and 2006 and these conditions most likely contributed to the declining abundance of this ESU.
(Winter-run 5-year Review, at p. 30.)