Unfavorable ocean conditions likely cause of low 2007 salmon returns along West Coast

Researchers from NOAA’s Northwest and Southwest Fisheries Science Centers are comparing data on the low food production of the California Current in 2005 that occurred when this year’s returning salmon would have been entering the ocean from their natal streams to feed and grow.

The cold waters of the California Current flow southward from the northern Pacific along the West Coast and are associated with upwelling, an ocean condition caused by winds that bring nutrients to the ocean’s surface and is the main source of nourishment for the ocean’s food web. In 2005 a southward shift in the jet stream, delayed favorable winds and upwelling for the California Current, which normally begins in spring. The winds instead arrived in mid-July, causing high surface water temperatures and very low nutrient production within the nearshore marine ecosystem.

“We are not dismissing other potential causes for this year’s low salmon returns,” said Usha Varanasi, NOAA Fisheries Service Science Center Director for the Northwest Region. “But the widespread pattern of low returns along the West Coast for two species of salmon indicates an environmental anomaly occurred in the California Current in 2005.”

Data released Thursday by the Pacific Fisheries Management Council indicate the 2007 returns of fall Chinook salmon to the Sacramento River in California’s Central Valley were approximately 33 percent of what fishery biologists expected. Projections for 2008 are substantially lower than last year’s estimate. [http://www.pcouncil.org/newsreleases/Feb_2008_Sacramento_News_Release.pdf]

Coho salmon returning to spawning streams in California and Oregon are also considerably lower than predicted. A preliminary analysis found an average 27 percent of the parental stock returning in 12 streams monitored in California. Even though coho returns appear to improve along the coast from south to north, Oregon Coast coho salmon had less than 30 percent of their parental stock return.

Coho salmon are listed as either endangered or threatened under the Endangered Species Act in the Central/Northern California and Southern Oregon watersheds.

Media Contact

Jim Milbury EurekAlert!

More Information:

http://www.noaa.gov

All latest news from the category: Ecology, The Environment and Conservation

This complex theme deals primarily with interactions between organisms and the environmental factors that impact them, but to a greater extent between individual inanimate environmental factors.

innovations-report offers informative reports and articles on topics such as climate protection, landscape conservation, ecological systems, wildlife and nature parks and ecosystem efficiency and balance.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors