THE DELTA – The Delta smelt are hovering at the brink of extinction, according to a new survey from the California Department of Fish and Game.
The native species, a prime indicator of overall health in the estuary, have reached their lowest point in 42 years of record-keeping.
The state agency’s fall population survey of fish species in the Sacramento-San Joaquin Delta was conducted in December.
It also found two non-native fish, the American shad and threadfin shad, at record lows.
State officials warned that unless winter gets a lot wetter, conditions will worsen.
The Delta is a freshwater source for two-thirds of California’s population and millions of acres of farmland.
Drought, pesticides and herbicides, invasive species and state water pumping are some of the factors contributing to the region’s troubles.
Water diversions last year were cut by 30 percent to protect fish.
The slowdown in deliveries cost the California economy at least $300 million, according to Fish and Game estimates. Water contractors already have been warned they might only get 15 percent of average Delta water deliveries because of an ongoing drought.
The state needs a deluge of water over several days to refill reservoirs, Department of Water Resources Deputy Director Ralph Torres said.
Smelt are finger-length fish that serve as a crucial food source for sportfish.
State biologists have warned that the Delta is changing – with warmer, more stagnant water and the disappearance of seasonal shifts in temperature and salinity.
The Associated Press contributed to this report