Interesting and controversial (only because the salmon, because of hatcheries, are doing fine) article from the East Bay Express about this.
“Mike Hudson began commercially fishing about 25 years ago. Fishing was productive enough that he paid off his boat and made some decent money — especially from his primary target, Chinook salmon, the most valuable seafood from local waters.
“I was able to turn this into a pretty hopping little business,” said Hudson, who has sold his fish for years at the Berkeley and El Cerrito farmers markets.
“But a little more than ten years ago, the Chinook population collapsed — the outcome of unproductive ocean conditions combined with excessive water diversions from the Central Valley rivers the salmon spawn in.
“The salmon fishing season in California and Oregon was closed for 2008 and 2009 while fishermen sought federal disaster relief. Eventually, salmon numbers rebounded, and fishing resumed. “But then the numbers started dropping again,” Hudson said.
“By 2016, 2017, and 2018, fishing was so poor that it barely paid Hudson’s gas bill. 2019’s season was “decent,” he said, but he fears another drop in salmon numbers will force him to sell his boat.
“Hudson’s perspective only captures the tail-end of a 150-year decline in salmon abundance in a state where, prior to the Gold Rush, fat, gleaming Chinook in uncountable swarms were perhaps California’s greatest asset. They teemed in coastal ocean waters while mature adults by the millions swam through the Golden Gate and Carquinez Straits each year and into the Central Valley’s rivers, which ran clean and unobstructed by dams and levees. Here, they laid and fertilized their eggs, then died as Pacific salmon naturally do after spawning. Their carcasses nourished wildlife, forests, and their own offspring. The huge volumes of fish impressed early explorers, who often described rivers brimming with three- and four-foot salmon. Meanwhile, for indigenous Californians, salmon was a plentiful year-round staple.
“European Americans and their unsustainable economies changed all this. Gold Rush mining activity filled spawning streams with silt, smothering egg-laying gravel beds. Logging caused similar erosion. Levees dried out riverside habitat, which was converted into farmland and towns. In the 20th century, when California began damming its biggest rivers, salmon lost access to their historic mountain spawning grounds.
“Then, in the 1950s and 60s, water agencies installed powerful pumps at the south edge of the Sacramento-San Joaquin Delta. These pumping facilities suck large volumes of water from the estuary and send it south into the San Joaquin Valley, where vast orchards have grown in recent decades. Those diversions have contributed to the collapse of the Delta’s ecosystem and its native fish.
“Since 2015, the state’s commercial fishermen have reported nearly record-low catches. Fish hatcheries produce most of the salmon caught in California today, and with much of their inland habitat badly degraded, truly wild salmon are scarce.
“But a small circle of biologists and fishermen believe they can revive California’s legendary Chinook to something resembling its historic glory.
“The potential for salmon recovery is massive,” said biologist Rene Henery, who works with the organization Trout Unlimited. “We still have diverse habitat, we still have a ton of water, we still have high-elevation places where we continue to get snowpack, and we still have large floodplains.”
“Floodplains covered with water provide important foraging grounds for young salmon as they migrate downriver to the ocean. However, thousands of miles of levees now separate rivers from adjacent land, turning once productive waterways into narrow, fast-moving, sterilized channels — a terrible environment for young salmon.
“Henery believes that reconnecting floodplains to their rivers could help reboot salmon runs in the Sacramento watershed, in spite of upstream dams like Shasta, Oroville, and Folsom.
“Jacob Katz, a biologist with California Trout, sees the same potential. Katz has been working for more than half a decade on a plan to carve a relatively simple notch into a levee along the lower Sacramento River that will allow river water to flow across 8,000 acres of low-lying land. Rice farmers own much of this property, but the idea is to flood it only during the fallow winter months. Spring and summer farming would not be impacted, and river productivity — magnified by increased surface area, solar exposure, and blooms of nutritious floodplain invertebrates — would surge.
“Combined with other “landscape-scale” projects, Katz believes this work could reenergize the Central Valley’s salmon rivers.” Retrieved January 8, 2020 from https://www.eastbayexpress.com/oakland/californias-salmon-barely-survived-the-20th-century-but-will-they-vanish-before-the-next-one/Content?oid=28373626