Experiment To Boost Smelt's Food Supply Shows Promising Results

An experiment to improve conditions for the endangered Delta smelt appears to be working.

Scientists are trying to boost the smelt's food supply chain by creating a bloom in tiny plants called phytoplankton.

"We need the green stuff in order to grow zooplankton, the small microscopic shrimp that Delta smelt rely on," says Ted Sommer, the California Department of Water Resources' lead scientist on the project.

Sommer says state, federal and local water districts released water through the Yolo Bypass - a wetland and tidal slough corridor of the Sacramento River system - and into the Delta, where it created a ten-fold increase in phytoplankton.

Some Central Valley farmers blame efforts to save the smelt for reducing water supplies. But Sommer says for this experiment, the water was only redirected.

"Water was diverted from the Sacramento River, run through the Yolo Bypass, but then it flows right back into the Sacramento River," says Sommer. "So it's still available downstream."

The project is part of a larger effort to save the endangered smelt, called the Delta Smelt Resiliency Stragegy. Scientists are also studying whether to add sand - used by smelt for spawning - in some Delta areas.