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Contact: Tina Swanson, The Bay Institute, (415) 272-4501
Jeff Miller, Center for Biological Diversity, (510) 499-9185
Kate Poole, Natural Resources Defense Council, (415) 875-6100

Conservation Groups Request State Endangered Status
For Disappearing Delta Smelt

Emergency Petition Filed As Fish Populations Collapse and Delta Ecosystem Unravels

San Francisco – Conservation groups today submitted a 57-page petition to the California Fish and Game Commission requesting emergency listing of the delta smelt (Hypomesus transpacificus) as an endangered species under the California Endangered Species Act. The species is currently listed as threatened under the state law; in March 2006 the organizations also petitioned to change the fish’s federal listing from threatened to endangered.

The delta smelt is a small, nearly translucent fish found only in the upper San Francisco Bay and Sacramento-San Joaquin Delta. It was once one of the most common and abundant of the Delta’s open water fishes, but in the 1980s its population plummeted by more than 80 percent. The species was listed as threatened under both the state and federal endangered species acts in 1993. In recent years the species’ population has completely collapsed, and abundance levels the past three consecutive years have been the lowest on record. In 2005, smelt abundance was the lowest ever measured at just 2.4 percent of its population in 1993; the 2006 and 2004 abundance levels were the second and third lowest respectively.

“The science is even clearer and more compelling than it was a year ago. Delta smelt, one of the best indicators of environmental conditions in California’s most important estuary, are in critical condition due to reduced freshwater inflows, record-high water diversions, and harmful non-native species that thrive in the degraded Delta habitat,” said Dr. Tina Swanson, senior scientist with The Bay Institute. “It’s time for the state and federal resource agencies to apply this information to protect this species and its habitat before it’s too late.”

“Delta smelt are on a rapid trajectory toward extinction and clearly need more state and federal protection,” said Jeff Miller of the Center for Biological Diversity. “The recent collapse of the estuary’s major fish populations is dramatic evidence that government agencies have utterly failed to address the decline of the Bay-Delta ecosystem. They cannot continue to approve record levels of water diversion at a time when the entire Delta ecosystem is in crisis.”

“The delta smelt is an estuarine version of the canary in the coal mine, and its plummeting numbers show that the Delta is on the verge of collapse,” said Kate Poole, senior attorney with Natural Resources Defense Council (NRDC). “Urgent action is needed to protect Delta habitat and water quality, for the benefit of the smelt and the 20 million Californians who depend on the Delta for clean drinking water.”

Delta smelt spend their entire lives in the Delta, the west coast’s largest estuary, swimming in shallow open waters at the interface of inflowing fresh water from the Sacramento and San Joaquin Rivers and salt water from the ocean. Threats to the species include reduced freshwater, massive and increasing diversions of fresh water from the Delta and its tributary rivers, loss of habitat, impaired water quality from pesticides and other pollutants, and competition and predation from introduced species. The current management of smelt habitat is “dangerously unsustainable” according to a report released today by the Public Policy Institute of California, Envisioning Futures for the Sacramento-San Joaquin Delta, which warned that the Delta “could become an environmental and economic disaster.”

The Delta is a major hub for California’s water system. The State Water Project, federal Central Valley Project and thousands of private water diversions take as much as 65 percent of the Delta’s total freshwater inflow, killing both spawning adult delta smelt and their young in pumps and diversions. At times, pumping levels are so high they reverse flow in the San Joaquin River, confusing and delaying adult fish migrating upstream, impairing downstream transport of larval and juvenile delta smelt from the upper estuary to their brackish water rearing habitat, and drawing water and fish into the pumps. Hydraulic models indicate that when water export rates are high, virtually all young smelt in the southern Delta are sucked into the pumps. The recent decline of Delta fish species coincides with significant increases in water exports by the state and federal water projects (seasonal exports in the 2000s are up to 49 percent higher than in the early 1990s) and higher mortality of smelt at the pumps. The five highest years of water exports from the Delta have occurred since 2000.

New scientific analyses show that recent record-high Delta water exports are related to the delta smelt population decline. Recently published population viability analyses indicate that the species has a 50 percent probability of going extinct in the next 20 years. However, despite this new information and crashing fish populations, state and federal agencies charged with protecting the smelt and its habitat have taken no actions to reverse the decline. Incredibly, state and federal agencies recently proposed increased water diversion and storage projects that would have exacerbated conditions for delta smelt. Fortunately, the proposed “South Delta Improvements Program” was effectively halted earlier this year when the National Marine Fisheries Service discontinued consultation on the project. The CALFED Bay-Delta Program, promoted as a solution to reducing the negative impacts of the federal and state water projects on fish and wildlife, has proven ineffective and now has largely collapsed.

The delta smelt is not the only fish species facing extinction in the Delta. Since 2002, scientists have also documented catastrophic declines of longfin smelt, threadfin shad and striped bass, and numbers of white and green sturgeon in San Francisco Bay and the Sacramento River have fallen to alarmingly low levels. The green sturgeon was listed as federally threatened in 2006. Today’s petition was submitted by The Bay Institute, the Center for Biological Diversity and NRDC.

More information regarding delta smelt is available on the Center for Biological Diversity Web site at

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