Delta fish continued to languish at very depressed levels in 2010, according to the latest numbers from the California Department of Fish and Game. A key annual survey performed each fall showed the Delta smelt population continues to hover at a level some biologists believe is near extinction, while year-old striped bass, a popular sport fish, dropped to a record low.
Not all the news for Delta fish is bad though. Salmon returns this year have been the strongest in a couple of years, leading to optimism that anglers may get more than the paltry eight-day fishing season commercial fishermen got in off California in 2010 — a season that followed two years of unprecedented closures.
Meanwhile, the water supply picture is also one of good news and bad news, while plans to find a long-term solution to the Delta’s problems await a new state administration and a pivotal scientific analysis expected in the next month or two.
The Sierra snowpack is about double the average at this early stage. But ongoing La Nina conditions — defined by colder-than-normal sea surface temperatures in the equatorial Pacific Ocean — can lead to drier winters later in the year, particularly in Southern California.
And while new environmental restrictions on pumping water out of the Delta have had only minor to moderate effects on pumping rates to date — despite the loud claims from politicians and national media figures to the contrary — the new restrictions could have a more substantial effect if 2011 becomes a wet year.
“I think the water is there. The question is going to be, ‘Are we going to be able to pump it?’” said Laura King Moon, assistant general manager for the State Water Contractors, which represents the Metropolitan Water District of Southern California and other customers of massive state-owned pumps in the Delta.
The fall index for Delta smelt rose to 29 in 2010, one year after dipping to an all-time low of 17.
Baby striped bass fell to 43, a record low.
Those fish, longfin smelt and threadfin shad, all plummeted in about 2002 and caused alarm a few years later when it was clear they were not rebounding.
The decline set off calls for new restrictions on Delta water pumping, which increased about the same time the fish populations dropped.
The Delta and San Francisco Bay form the largest estuary on the West Coast, and the Delta also is a key source of irrigation and drinking water for about two-thirds of the state.
Salmon, unlike smelt and other imperiled Delta fish, migrate through the Delta and spend much of their lives in rivers and in the ocean.
“(Salmon returns) are substantially up, but with the caveat that the return in 2009 was the lowest ever observed,” said Mike O’Farrell, a fisheries biologist at the National Marine Fisheries Service in Santa Cruz. “We are happy about that.”
The reason for their rebound is that when the adult salmon that returned this fall were babies in 2008, they migrated out of the Bay into the best feeding conditions in the Pacific Ocean in 25 to 30 years, said Bill Peterson, an oceanographer for the national fisheries service in Oregon.
Cold water in the northern Pacific that year encouraged currents that brought plenty of food to the California coast.
On the other hand, the shocking collapse in 2007 of the Sacramento River’s fall-run chinook salmon — the backbone of California’s commercial salmon fishery for more than a century — was largely due to extremely poor ocean conditions in 2005, when those fish migrated out to sea, Peterson said.
The summer of 2005 was “one of the worst ocean conditions we’ve ever had,” he said.
But, Peterson added, the health of California’s salmon population is not entirely dependent on natural fluctuations in the ocean.
Scientists have said that a string of very good years in the ocean masked deteriorating conditions in the Delta, and when ocean conditions flipped and food was scarce, the salmon population took a stunning downturn.
“It’s largely ocean, but I remind people it’s not all ocean. There are two parts to the story,” Peterson said.
Meanwhile, the Bay Delta Conservation Plan would build a new set of tunnels at a cost of more than $12 billion beneath the Delta to eliminate the disruptions caused by massive pumps in the south Delta. It would also create a new wetlands restoration program.
Analyses done so far have led government biologists to argue that the plan might harm fish rather than help them, a conclusion that could doom the project.
But consultants to water export agencies are redoing parts of the analysis and that work is expected to be done in January or February.
Complicating matters is the fact that big farm districts that would provide significant financing for the plan want at least as much water as they have been getting and guarantees that water will continue to flow.
If they drop out of the plan, the effort could implode because it shifts costs to other agencies that could, in turn, find the increased costs make their share uneconomical.