ABC 10 –
The Delta smelt is such a small and translucent fish that it often disappears from view when it swims in the turbid waters of its home in the Sacramento-San Joaquin Delta.
However, it’s also been disappearing from the Delta entirely.
“The Delta smelt has gone from being one of the more abundant fish in the Delta to being just on the verge of extinction today,” Peter Moyle, an Emeritus Professor of Fish Biology at UC Davis, said.
Moyle has been studying Delta smelt for over 40 years. In the 1980’s, he began to see a startling drop in the number of Delta smelt in his population samples. The fish was listed as threatened, then endangered, under the California Endangered Species Act. The California Department of Fish and Game’s Fall Midwater Trawl Survey keeps tabs on fish populations and last year’s results showed zero Delta smelt were in the wild.
There are more than a few factors pushing the Delta smelt toward extinction. Ted Sommer, lead scientist at the California Department of Water Resources, lists the historic droughts, rising temperatures, invasive species, contaminants, and the long-term conversion of natural marshland in the Delta to agriculture and cities, all as contributions to the Delta smelt’s decline.
“Delta smelt to some degree are getting it from all directions,” Sommer says.