Sacramento River salmon take a dive - jet stream course change to blame?
This article is an excellent demonstration of how the interaction of natural systems are so complex and can affect something that would not be obvious at first glance. Since cloudbusting is known to be able to change the course of the jet stream, and people on the West Coast, such as the notorious group of bunglers who call themselves the "C.OR:E. Network, have ignorantly meddled in the fate of the rest of the world by doing so in the past, the shift in the jet stream may or may not have been due to someone on the West Coast using a cloudbuster without knowing enough about ecology to use it responsibly. If that is what has happened this time, that person almost certainly would never have thought of the possible impact on fish populations as a consequence of cloudbusting. As cloudbusting becomes an ever-more popular hobby, it is necessary to keep reminding anyone who might feel like taking it up, that there can be such unintended results.
Sacramento River salmon take a dive
Fishery management officials, surprised by the decline, expect Valley Chinook to rebound.
By Matt Weiser - Bee Staff Writer
March 3, 2007
Story appeared in METRO section, Page B3
Fall-run Chinook salmon that make a home in the Sacramento River and its tributaries fell last year to their lowest numbers since 1992, according to estimates by the Pacific Fishery Management Council.
This is a surprise to fisheries managers, because the population was expected to be strong after commercial fishing was drastically curtailed last year to protect Klamath River fish. The rebound for Klamath salmon is likely to mean better fortunes for Pacific coast commercial fishermen this year.
But now the troubled Sacramento River salmon are the center of attention.
That population includes American River fall-run Chinook, and only 8,728 salmon returned to the Nimbus Hatchery on the river last fall, according to the state Department of Fish and Game. That's the smallest number since 1997, well below the 2005 return of 22,349 fish.
The fishery council meets in Sacramento next week to draft plans for the commercial salmon season, which starts May 1.
"We're looking at it and wondering what's going on," said Allen Grover, a fisheries biologist at Fish and Game who monitors salmon. "I think it is a little bit worrisome."
Last year's commercial salmon season was cut by 90 percent along 700 miles of California and Oregon coastline to protect Klamath River Chinook, which had declined drastically the prior three years due to river management problems.
The shortened season was necessary because Klamath fish mingle in the ocean with more numerous Sacramento River salmon, and it is impossible for fishermen to target just one group.
The abbreviated season helped: About 30,400 natural spawners returned to the Klamath River last fall, well above the 21,000 predicted initially. This year, 65,300 spawners are predicted.
"We're looking at certainly a less restrictive season than last year," said Zeke Grader, executive director of the Pacific Coast Federation of Fishermen's Associations. "The one area of concern is what the hell is happening with Central Valley stocks."
While early projections for 2007 call for a population increase, the big dip in last year's population caught researchers by surprise. The total population of Sacramento River fall-run Chinook was estimated at 435,000, about half its 2005 size. Of those, about 270,200 moved upriver to spawn, down from 394,000 in 2005.
A clue to the Sacramento River salmon decline emerged in a study published last week by the National Academy of Sciences. It documents a broad decline in Pacific Ocean food sources. Lead author John Barth, an oceanography professor at Oregon State University in Corvallis , said the cause was a southern shift in the jet stream in spring 2005.
That current of winds normally drives a deep upwelling in the ocean off Oregon and Washington that feeds the food chain. But the jet stream blew over California instead, disrupting ocean currents and causing a population decline among mussels and barnacles that feed on plankton.
"If you change the timing of this seasonal cycle, it doesn't provide the food for organisms that depend on plankton, and salmon are one of those species," said Barth. "If the food is not there when these organisms are naturally ready to make use of it, they're going to suffer."
Klamath River salmon may have been less affected by these changes because they don't range as far in the ocean as Central Valley fish.