Q & A on survival of California’s delta smelt 

William La Jeunesse and Petr Moyle. PhotoL Fox News and John Stumbos/UC Davis

William La Jeunesse, Los Angeles-based correspondent for Fox News recently interviewed Peter Moyle, UC Davis professor of fish biology, on the survival of the delta smelt  Photo: Fox News and John Stumbos/UC Davis

Four years of severe drought and decades of huge water diversions appears to have pushed delta smelt to the point of no return. State biologists netted only a single smelt last month in trawl of 40 sites in San Francisco Estuary, the species’ only home. The record-low catch came less than a month after UC Davis fish biologist Peter Moyle warned state officials to prepare for the smelt’s extinction in the wild.

Fox News correspondent William La Jeunesse recently spoke with Moyle about the survival of the much politicized tiny fish, a federally designated “threatened” species with protections that at times have curbed the flow of water to many cities and farms. The interview resulted in only 10 seconds of air time. However, the reporter and biologist later agreed to post on California WaterBlog this more insightful series of questions and answers they had drafted in preparation for the interview.

Q.  Given the latest smelt survey, is it fair to say the species can no longer survive on its own?

It is fair to say that most native species in the Delta cannot survive on their own; all require some form of human assistance. Smelt are just leading the pack as the species in greatest need of help. The goal now should be to keep the population from blinking out. Smelt populations won’t rebound during a drought, but if some fish survive, they could struggle back from the brink when precipitation and freshwater flows increase. The same is true for other species affected by environmental changes to the estuary.

Q.  This species was once one of the most abundant fish in the Delta. What happened?

The Delta is an incredibly altered place. The pace of change accelerated after the State Water Project went online in the mid-1960s and Delta exports increased. The resulting changes to the Delta ecosystem created conditions less favorable to native species.


Peter Moyle aboard a UC Davis research vessel in Suisun Marsh, has been studying delta smelt since 1975. Photo by Amy Quinton, Capital Public Radio

Exports continued to increase in the 1980s, even during droughts. Delta smelt populations declined and invasive species increased, reducing the smelt’s food supply and preying on its eggs and larvae. Delta flows dragged smelt through the lethal export pumps. Meanwhile, contaminants draining from farms and cities became more pervasive.

By the late 1990’s much of the Delta had become too warm and uninhabitable for smelt. This largely confined them to an arc of habitat from the North Delta to Suisun Bay in diminishing numbers. Then, in 2012, the current drought kicked in, making habitat conditions even worse for the fish.

Q.  Delta smelt supporters say it’s not about a single species, but rather an ecosystem of several native fish in need a healthy delta with natural freshwater inflows. Yet some farmers almost solely blame the delta smelt for massive reductions in surface water deliveries and suggest that if the species is “functionally extinct,” more water could be released. What is your take?

The Delta ecosystem has indeed changed in major ways that make it less habitable for native fish. The delta smelt is one of six government-protected fish species dependent on the Delta. The others are winter- and spring-run Chinook salmon, green sturgeon, longfin smelt and Central Valley steelhead. Several more are candidates for listing.

Those who blame the delta smelt for our water problems are in denial about the severity and frequency of natural droughts in California. In fact, the “water user” that has suffered most during this drought is the environment. From a fish perspective, California has been in an increasingly severe drought since the 1960s. This is reflected in the decline of delta smelt and other fish.

Photo: UC Davis

An adult delta smelt caught in a survey of fish in the Sacramento-San Joaquin Delta. Photo: U.S. Fish & Wildlife Service

In some years, Delta exports have been reduced by as much as 15 percent to protect delta smelt and winter-run Chinook salmon. But this water has benefited the entire Delta ecosystem, which has steadily been deprived of its freshwater inflows over the years.

Most of the fresh water that “flows to the sea” comes into the Delta during the summer to protect Delta farming. This water also keeps salt water away from the big pumping plants that export drinking water to our cities and irrigation water for farms. In addition, about half the river water is diverted before it even reaches the Delta.

So, while at times “Delta smelt water” could have provided more water for export, those amounts were small and certainly not nearly enough to alleviate drought conditions.

Q.  What is the case for saving a fish that many call unremarkable and lacking any commercial value? Why should taxpayers spend millions to save it?

Caring for delta smelt is caring for the Delta. This fish is a good indicator of the estuary’s health. If delta smelt are alive and well, other fish, birds, mammals and plants also will thrive.

The delta smelt is a part of California’s heritage. It is one of more than 80 fish species found only in California. Most are in decline. Conserving these California-only species means conserving unique aquatic habitats throughout the state. So caring about these native fish is really about caring for what’s unique and special about California’s environment.

The smelt is really a beautiful little fish, very delicate and translucent. Japanese harvest a similar smelt species and value it highly for its delicate flavor. I would like to see the delta smelt become so abundant that we could harvest it for export to Japan, like almonds.

Through enactment of the state and federal endangered species acts, the people of California and the nation have deemed it immoral to allow a species to go extinct, if preventable. The laws tell us we should be taking extraordinary measures to prevent extinction.

I see the plight of delta smelt as a test of our willingness as citizens of California to protect our very special fauna and flora for future generations to enjoy and admire. Nevada fish biologist Jim Deacon was lauded for protecting big places through little animals. Wouldn’t that be a great way for our generation of Californians to be remembered?

Q.  What are they doing at the UC Davis Fish Conservation and Cultural Laboratory to save the delta smelt?

This hatchery program was set up in 2007 as a hedge against the smelt’s extinction in the wild and a source of fish for laboratory studies of the species’ physiology, toxicology and behavior.

Delta Smelt Refuge facility with tanks for genetically diverse smelt populations.

Delta smelt rearing tanks in captive breeding facility run by UC Davis near Stockton. Photo by Dale Kolke/California Department of Water Resources

Thanks to Joan Lindberg and Tien-Chieh Hung, the lab became one of the most sophisticated aquaculture operations in the world. Mating is carefully controlled. A few wild smelt are brought in each year to mate with hatchery smelt to avoid creating fish more adapted to the hatchery than to the wild. About 20,000 artificially propagated, genetically diverse smelt are there at any given time. This is an extraordinary accomplishment given how delicate these fish are.

Q.  What do you see as the policy failures by water agencies, both on water supply and demand?

I am a fish expert, not a water expert, so I will try to answer this from the perspective of fish.

I did my first statewide assessment of California native fishes in 1975 and, as far as I could tell, most were doing okay — including delta smelt. But after that, conditions for native fish quickly deteriorated.

Until the 1980s, water policy largely ignored fish, except salmon. Even then, it was largely thought hatcheries could solve all problems. As water projects developed, the fish clearly needed legal protection. But the needs of fish were largely ignored.

Water management increasingly failed to protect Delta fishes during the 1980s and 90s, resulting in the listing of six species under the federal and state endangered species laws. The listings brought attention to the fish but real action was delayed while studies were being done – studies that never seem to be finished.

Though water in California is over-allocated, the water agencies made optimistic assumptions about water availability for fish and were optimistic about engineering their way out of shortages.

Our understanding of how much precipitation is “normal” for California is based on a short record. Analyses of tree rings and other data suggest extended droughts are common in California and other parts of the West, but our water management seemingly continues to be based on a period when we had a lot of rain and snow and little concern for fish.

The most recent manifestation of this mindset is the “coequal goals” mandate of the state’s Delta Stewardship Council and the Bay Delta Conservation Plan. Under this principle, future provisions of water for environment and for human use would have equal weight.

The problem is that water for the environment — water for fish — is already way under-allocated. Truly balancing human and environmental needs would inherently require allocating more water for the environment.

Fox News anchor Chris Wallace questions correspondent William La Jeunesse on the fight over the delta smelt amid the California drought. The national story aired April 30. Click on image to view story.

Fox News anchor Chris Wallace and correspondent William La Jeunesse report on the fight over the delta smelt amid the California drought. The national story aired April 30. Click on image to view story.

Further reading

Bennett WA. 2005. “Critical assessment of the delta smelt population in the San Francisco Estuary,” San Francisco Estuary & Watershed Science News

Boxall, B. “A small fish caught in a big fuss.” Los Angeles Times. Feb. 2, 2011

Fox News. “Fight over saving endangered fish amid California drought.” April 30, 2015

Moyle, PB. 2015. “Prepare for extinction of delta smelt.” California WaterBlog. March 18, 2015

Quinton, A. 2015. “Endangered delta smelt may be extinct.” Capital Public Radio. March 16, 2015

Ruyak B. 2015. “UC Davis fish biologist: delta smelt ‘functionally extinct’.” Capital Public Radio, Insight with Beth Ruyak. March 18, 2015

This entry was posted in Delta, Delta Smelt, Drought, Fish, reconciliation and tagged , , , , . Bookmark the permalink.

9 Responses to Q & A on survival of California’s delta smelt 

  1. tsac0008 says:

    The technology for filtration prior to export pumping, that could prevent smelt and or their fry from being destroyed, is well known and could be easily adapted for a very small cost. The use of infiltration galleries and similar designs is quite common as are well pumping designs from Driscoll and others. The incompetence of federal and state engineers that have worked on these projects is second to none. The hydraulic carrying capacity of the two, smooth wall, 40 ft. diameter tunnels exceeds the flows of the Sacramento River under extreme drought conditions.

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