Minnows and shiners

Delta Smelt Delta Smelt
Hypomesus transpacificus

Endangered Status

The Delta Smelt is on the U.S. Endangered Species List. It is classified as threatened throughout its range in California, where it occurs only in Suisin Bay and the Delta in San Francisco Bay, at the mouths of the San Joaquin and Sacramento Rivers. In the late 1950s the first of two large water export facilities began pumping water out of the Delta, and then in 1967 the second large facility started up, pumping even more water. Pesticides and herbicides began showing up with more frequency, which led to increased contamination of the Delta. And ships from China and elsewhere came to San Francisco and dumped their ballast water, which infected the Delta with invasive organisms, exotic species of zooplankton and a voracious plankton eating clam.
From that point, the ecological environment of the Delta was radically changed and damaged, and Delta Smelt numbers began declining in the 1970s, plunging in the early 1980s to worrisome levels. Delta Smelt was listed under the Endangered Species Act in 1993, and have declined to the edge of extinction today.