Building a defense against extinction

Rio Vista, Calif. - The group of low-slung, nondescript buildings in a remote corner of San Joaquin County near Tracy are hardly noticeable and are not open to the public.

Inside, scientists are cultivating a slender, silvery minnow-like fish species with the aim of staving off its extinction, and reverse the course of decline of the long-troubled  Delta smelt. 

Since its listing by  the Endangered Species Act  30 years ago, the Delta smelt has been the focus of an intense, comprehensive plan to protect the dwindling wild population, and in recent years to kick-start its recovery. Those years have been marked with barely perceptible advances that only protect against extinction, with occasionally noteworthy occurrences such as the release of thousands of fish via boat or tanker truck.

Such was the case on a recent winter morning as some 25,000 Delta smelt made the 50-mile trip via  tanker truck from the U.C. Davis Fish Conservation  and Culture Laboratory near Tracy to the chilly, murky waters of the Sacramento River at Rio Vista.

Cultivation and release of Delta smelt is a multi-faceted effort involving the expertise and dedication of dozens of personnel with Reclamation, the U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, California Department of Water Resources, U.S. Geological Survey, and U.C. Davis.

Bertrand said he was introduced to the Delta smelt’s dilemma in the early 2000s in Texas when it was the subject of a segment on The Daily Show spotlighting the fish’s struggles and its use as a political football within the controversial world of California water. Since then, the smelt’s fortunes have dwindled as a multitude of ecological stressors push it to the brink of extinction.

"It's death by a thousand cuts," said Bertrand, describing the many ecological challenges facing the population.

The smelt are released after spending the first 200 days of their life at the U.C. Davis laboratory. Incubating, raising and marking them for release is a precise, calculated and labor- intensive process. They are a fragile, temperamental fish, and releases are carefully orchestrated to ensure they have the best chance for survival.

“We would like to see the population in the wild have a good recruitment by themselves without the need of the supplementation of lab-bred fish,” he said. “That would be considered a success.”

"We have demonstrated that we can transport them from the facility to the wild [and] we are doing mini experiments to ensure that process isn’t too stressful.”

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