For sixth year in a row, no Delta Smelt found in CDFW Fall Midwater Trawl survey

For the sixth year in a row, no Delta Smelt were collected in the California Department of Fish and Wildlife’s Fall Midwater Trawl (FMWT) Survey in the Sacramento-San Joaquin River Delta from September through December 2023.

Once the most abundant species in the entire estuary, the Delta Smelt has declined to the point that it has become virtually extinct in the wild. The 2 to 3 inch fish, found only in the Delta, is an “indicator species” that shows the relative health of the San Francisco Bay/Delta ecosystem.

When no Delta Smelt are found in six years of a survey that has been conducted since 1967, the estuary is in a serious ecological crisis.

The Delta smelt is listed as “endangered” under both the federal Endangered Species Act and the California Endangered Species Act.

“No Delta Smelt were collected at any stations from September through December,” reported Taylor Rohlin, Environmental Scientist for the CDFW Bay Delta Region, in a memo published on Jan. 25. “The 2023 September-December index (0) is tied with 2018-2022 as the lowest index in FMWT history.”

She said the absence of Delta Smelt catch in the FMWT is “consistent among other surveys in the estuary.”

For example, the Enhanced Delta Smelt Monitoring (EDSM) survey of the U.S. Fish and Wildlife Service (USFWS) caught only 5 Delta Smelt among 10 sampling weeks (between 9/4 and 11/10) comprised of 1,360 tows (U.S. Fish and Wildlife Service 2023). 

Meanwhile, the other pelagic species collected in the survey — striped bass, Longfin Smelt, Sacramento Splittail and thread fin shad — continued their dramatic decline since 1967 when the State Water Project went into effect. Only the American shad shows a less precipitous decline. The graphs in this CDFW memo graphically illustrate how dramatic the declines in fish populations have been over the years: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentId=219831&inline

Experimental hatchery Delta smelt program continues  

Since 2022, the Interagency Ecological Program (IEP), a consortium of nine member agencies, including three State departments and six Federal agencies, has experimentally reintroduced thousands of hatchery-raised Delta smelt from the UC Davis captive breeding facility in Byron back into the estuary, according to the U.S. Fish and Wildlife Service. 

“The Delta Smelt Experimental Release Study involves releasing 90,000 laboratory-raised fish into the Delta this season to determine which methods prove the most effective at production, tagging, transport and release of the fish into the wild. Learning which plan works best could someday help to supplement the population with a goal of aiding in the recovery of the species,” the CDFW wrote in their California Outdoors Q&A: https://wildlife.ca.gov/COQA/whats-the-latest-on-cdfws-experiment-with-the-delta-smelt-population

“Recently 32 metal 20-gallon containers were filled with 200 Delta smelt and emptied directly into the Sacramento River into a specially designed submerged cage, the agency stated. The cage provided a safe environment while the fish adjusted to the river temperature and their new surroundings before they were fully released a few hours later into the river,” the agency reported. 

Through Delta smelt monitoring surveys that are conducted routinely each year, CDFW said it can learn about their health and survivability.

“Last year was the first time we were able to uniquely mark fish from different experimental release events and get decent numbers of adult fish recaptured in our monitoring surveys,” said CDFW Environmental Program Manager Dr. James Hobbs. “We’re releasing adult fish just before the spawning season, and we’re hoping these fish will meet up and produce the next generations.”

“Unfortunately, the same factors responsible for the near disappearance of the fish are still present including a less than reliable flow of freshwater, low food productivity, loss of wetland habitats, predation by non-native species and other reasons. But scientists say the experiment is showing some positive results with survival and recovery of released adults,” CDFW concluded.  

However, if the experiment is showing “showing some positive results” as CDFW claims, why were no Delta smelt, hatchery or wild, found in the FMWT survey at their extensive monitoring stations throughout the estuary in 2023? And why were only 5 smelt collected in the Enhanced Delta Smelt Monitoring (EDSM) survey of the U.S. Fish and Wildlife Service in 2023?

Entire Delta ecosystem is collapsing

The near-extinction of Delta Smelt in the wild and the collapse of striped bass, Delta smelt, longfin smelt, American shad, splittail and threadfin shad populations documented in the fall survey is part of the larger Pelagic Organism Decline (POD) caused by massive water diversions from the Delta by the state and federal water projects, along with toxics, water pollution, invasive species and other factors.

Between 1967 and 2020, the state’s Fall Midwater Trawl abundance indices for striped bass, Delta smelt, longfin smelt, American shad, splittail and threadfin shad have declined by 99.7, 100, 99.96, 67.9, 100, and 95%, respectively, according to the California Sportfishing Protection Alliance.

Meanwhile, Governor Gavin Newsom is forging ahead with the environmentally destructive Delta Tunnel, Sites Reservoir and Big Ag-backed voluntary agreements, This will only make the ecosystem crash even worse by exporting more water to corporate agribusiness interests south of the Delta.  

There is no doubt why Governor Newsom is backing the Delta Tunnel, Sites Reservoir and the voluntary agreements— to serve the wishes of his corporate agribusiness contributors and other Big Money donors.

For example, agribusiness tycoons Stewart and Lynda Resnick, owners of The Wonderful Company and major promoters of the Delta Tunnel and increased water pumping from the Sacramento-San Joaquin River Delta, have donated a total of $431,600 to Governor Gavin Newsom since 2018, including $250,000 to Stop The Republican Recall Of Governor Newsom and $64,800 to Newsom For California Governor 2022.

Newsom received a total of $755,198 in donations from agribusiness in the 2018 election cycle, based on the data from http://www.followthemoney.org. That figure includes a combined $116,800 from Stewart and Lynda Resnick and $58,400 from E.J. Gallo, combined with $579,998 in the agriculture donations category.

Photo: DWR Environmental Scientist Trishelle Temple releases Delta smelt into a cage as part of an experimental soft release. The fish acclimate in the cage for 48 hours before being released into the Sacramento Deep Water Ship Channel. Photo courtesy of DWR.