
The Delta smelt, once the most abundant fish in the entire Sacramento-San Joaquin River Delta, has come closer and closer to extinction in the wild in recent years.
In the first month of the fall midwater trawl survey, September, zero Delta smelt were caught in the survey. The Delta smelt, constantly maligned by San Joaquin Valley agribusiness interests, is an indicator species, found only in the estuary, that demonstrates the health of the ecosystem.
Conservationists, scientists, and anglers are hoping that this fall’s midwater trawl survey won’t be a repeat of 2018, when the California Department of Fish and Wildlife found zero Delta smelt in the months of September, October, November, and December.
In 2017, only 4 Delta smelt were caught, 2 in October and 2 in December in the CDFW’s trawl survey.
An array of factors are behind the demise of Delta smelt and other fish species, including toxic chemicals, pollution, changes in dam operations, and invasive species, but none is more significant than the export of massive quantities of Delta water through the State Water Project and federal Central Valley Project pumping facilities in the South Delta.
The disturbing September data on Delta smelt comes as the Trump administration released new, much weaker, rules stripping protections for Central Valley salmon and Delta smelt on October 22. They received a clear warning from the National Marine Fisheries Service in July that stripping protections would illegally jeopardize salmon and other species, said John McManus, President of the Golden State Salmon Association.
In September, the CDFW also reported low numbers of longfin smelt, a cousin of the Delta smelt. The index, a relative measure of abundance, was only 11, compared to last September’s index of 13. The total index last year was 52.
Sacramento splittail, a native minnow found only in the Sacramento River and Delta, didn’t fare well this fall to date either, with zero fish reported in the September trawl survey.