Smelt deaths again prompt lawsuit that aims to suspend water exports

Warning that a recent boost in water exports is nudging the delta smelt closer to extinction, environmentalists have asked a federal judge to order state and U.S. officials to cut back pumping that imperils the tiny fish.

Increased pumping into aqueducts that move water as far south as San Diego has swelled the number of smelt that have been sucked into pumps and killed in recent days.

U.S. District Judge Oliver W. Wanger in Fresno is scheduled to hear arguments Friday that could curb southbound water shipments at least temporarily to help the smelt, a native of the Sacramento-San Joaquin River Delta. The lawsuit was brought by Natural Resources Defense Council and Earthjustice.

“What happens over the next week could be the difference between survival and extinction for this species,” said Bill Jennings, executive director of the California Sportfishing Protection Alliance.

The latest court fight follows months of wrangling between environmentalists and water managers over how to balance the plight of an endangered fish with water demands from Central Valley farmers and urban areas such as Los Angeles, which this year is experiencing record-low rainfall.

Each spring, mammoth pumps that supply the state and federal aqueducts rev up to meet demand. The pumps are so powerful that they can reverse the flow of water in nearby delta channels. The diminutive smelt, which are notoriously poor swimmers, can fall prey to their tug and perish.

As the delta water warms in late spring to temperatures considered lethal to smelt, the fish typically flee to colder water near San Francisco Bay -- where they would be out of the range of the pumps. But this year the native delta fish have lingered, probably because cooler weather in the Central Valley and cold releases from upstream reservoirs have kept delta water temperatures lower.

“Life for the smelt is looking worse and worse,” said Kate Poole, senior attorney with the Natural Resources Defense Council.

State and federal water managers recently have taken steps to stem the death toll, curtailing pumping for nine days this month. It was the first time since 1999 that the pumps have been shut down for the smelt.

But when water exports ramped up in earnest again last weekend, the number of smelt fatalities soared, reaching an estimated 180 deaths on Sunday and an additional 90 on Monday. Most of the fish were sucked into state pumps that feed the California Aqueduct.

Jeff McCracken, a U.S. Bureau of Reclamation spokesman, said federal water managers remained confident that their pumps were being properly managed to ensure smelt survival. He said recent days have seen conditions take a turn, with warmer water prodding the fish to flee parts of the delta near the pumps. The federal pumps are now operating at full tilt.

Christina Swanson, a fisheries biologist who has studied the smelt for more than a decade, said the fish face “an imminent risk” of extinction. Smelt are protected under the federal Endangered Species Act.

In court papers, Swanson said the plummeting smelt population had shrunk to an unprecedented low in recent years. A recent survey found that the number of juveniles stood at less than one-tenth of normal.

If sufficient numbers of young fish don’t live to become spawning adults, the species may not survive, Swanson said. “We may already have fallen below this threshold.”

Although the temporary reduction in water exports isn’t expected to prompt any mandatory cutbacks in Southern California, officials at the Metropolitan Water District -- which gets 60% of its water from the delta -- are urging Southland residents to conserve.

Whatever the outcome, the smelt predicament has cast a spotlight on the fate of the delta, considered by environmentalists to be an ecosystem in collapse. A congressional subcommittee led by Rep. George Miller (D-Martinez) has planned a Bay Area hearing July 2 to address the delta’s environmental troubles and the movement of water between Northern and Southern California.

Scientists say pumping is just one factor that has been contributing to the demise of smelt, a key indicator species for the delta. Toxic contaminants also have caused problems, and invasive species have rearranged the delta food chain.

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eric.bailey@latimes.com