Despite increase in rains, Delta smelt still floundering
STOCKTON — The Delta smelt has survived 2016, but that’s about where the good news ends.
Surveys that wrapped up this month revealed no real increase in smelt numbers despite a wetter year with more freshwater flow in the Delta.
In fact, the smelt’s situation may actually have gotten worse: For the first time since the extensive fish surveys began in the late 1960s, officials found smelt just one month out of four. In their many hours spent trawling the Delta with nets from September through December, they found a total of seven smelt, all of them in November.
Last year surveyors found six fish, the lowest number on record.
“The only result that’s clear is that Delta smelt are still here,” said Jon Rosenfield, a biologist with environmental group The Bay Institute. “We don’t really know whether there are fewer or more (than last year). We just know that they are just about as close to extinction as you can get.”
The smelt are on the verge of becoming the first species to disappear in the Delta since the thick tail chub, last seen in 1957.
While small and seemingly insignificant, the smelt is considered a bellwether species. Its well-being reflects the health of the Delta as a whole. But the fish has suffered from reductions in freshwater flow, water exports, pollution from farms and cities, loss of habitat and other problems.
It’s not entirely clear why there was no rebound in the smelt population this year. During a very wet 2011, the population increased 10 times over before crashing back down to near-historic lows the following year.
One clue may be found in the number of adult smelt that are able to spawn. Using mathematical models, the U.S. Fish and Wildlife Service last year began estimating the actual number of fish in the estuary, which had never been done before.
Experts now believe that when spawning began in early 2015, there were about 112,000 smelt in the Delta — an alltime low.
At the beginning of 2016, there were about 13,000 smelt in the Delta.
So, while water conditions were better this year, there were substantially fewer fish to begin with. Delta smelt live just one year, so if the increasingly spread-out adults cannot find each other to spawn, the species is in trouble.
The latest surveys show other species continuing to struggle, as well. Striped bass, a nonnative fish that is popular among fishermen, saw modest improvement this year but is nowhere near its historic abundance.
Bill Jennings, director of the Stockton-based California Sportfishing Protection Alliance, said he was “disappointed” that imperiled fish didn’t fare better and blamed water pumping operations.
“Normally in a year like this with a good, wet fall, you’d have seen a significant rebound in the fisheries,” he said. “We’re not seeing it. We’ve taken them down to incredibly depressed levels.”
In 2016, just over 40 percent of the water in the Delta watershed was allowed to flow out to San Francisco Bay without being diverted, stored or pumped south. That’s far less than the amount of water scientists have said the ecosystem would need in order to recover from its downward spiral, if human needs were set aside.
News about the latest survey results comes two weeks after President Barack Obama signed legislation allowing water managers to pump more Delta water to areas of the state still stricken by the drought. The new law allows officials to pump the maximum amount of water allowed under rules intended to protect the fish under the Endangered Species Act, and to exceed maximum pumping levels during storms when rivers are flush with water.
At times this winter, officials have scaled back Delta pumping to protect fish, though scientists who advise Delta water operations have urged more aggressive cuts.