Because of those estimates, fishing during the fall chinook run has been banned since 2007.
In 2007 and 2008, there were 93,224 and 71,803 fish counted, compared to 280,152 in 2006, according to DFG.
With winter run chinook on the endangered species list and spring run chinook on the threatened species list, only the late-fall run chinook are open to fishing.
As the DFG moves to estimate the salmon count through tagging, marking dead fish and pooling information between fish hatcheries and tributaries, it expects to find less than 122,000 in the 2009 fall run, said Randy Benthin, a senior fishery biologist for the DFG.
Of those, as few as 5 percent may be jacks, which help the department forecast the 2010 fall run and determine whether fishing will be allowed.
Fish counts may pick up when the Red Bluff Diversion Dam's system of diverting water is replaced by a water pumping station, but abrupt drops in salmon populations can also come from changes in water temperature.
a drought in the late 70s, during which water was distributed without regard to the fish, winter run chinook salmon passing through the diversion dam dropped from 24,735 in 1977-78 to 2,339 the next year, Benthin said.
They went ahead and gave full (water) deliveries to all their customers, and so the river really heated up when the eggs were in the gravel, and that killed off most of them, he said.
The species has remained on the endangered species list since.
County Fish and Game Commissioner Scott Ferris said no one thing can account for struggling native salmon populations, but a broken food chain and an increased demand for water are at least in part responsible.
Because California's population is growing even in the third year of drought, some biologists fear a full comeback may be impossible, Ferris said.
The dwindling fish population marks a sharp change from 1951, when Ferris moved to the north state. Back then, he would catch salmon 12 months a year.
I thought I'd never see the day you couldn't catch a salmon, Ferris said.
