Drought, or Stupid Rescue Killing Delta Smelt?

At present, California is in the middle of a drought. Despite the news calling this the ‘worse ever’, it isn’t. California has had far worse droughts in the past. Some lasting hundreds of years.

This got me wondering: “Given that the Delta Smelt survived those droughts, why do they need our help in this one?”

Well, it seems that it isn’t just the water that’s an issue.

The narrative in the news is that we need to flush roughly 1/3 of the available fresh water through the San Francisco bay / delta system to keep the delta smelt happy and reproducing. Since brackish water can only migrate a little ways up stream, I find that hard to believe as well. All those folks using water in the central valley have it return to the drainage system anyway, and last I looked the Sacramento River still flowed. But even if we ignore those questions (of the form “wasn’t the water lower than this in the 200-ish year drought that ended the Anasazi” ) and accept that fresh water levels are lower, is that low enough to cut the population of delta smelt down to near nothing? (Some news reports have claimed it might be as low as a few hundred fish. For something 2 inches long, that’s about enough to fill one tiny pond… and I’m sure there is at least that much appropriate habitat along the delta somewhere. I’ve boated and fished there my whole life and it is a huge place.)

Something about the whole story just seemed wrong. So I took a look. What I found sure looks a lot more like the delta smelt is dying out from a stupid “rescue” attempt and that no amount of fresh water can change that. We’ll start with the wiki, and with it’s green bias, anything other than water that gets through that filter will be pretty well undeniable.


Delta smelt, Hypomesus transpacificus, is an endangered slender-bodied smelt, about 5 to 7 cm (2.0 to 2.8 in) long, in the Osmeridae family. Endemic to the upper Sacramento-San Joaquin Estuary of California, it mainly inhabits the freshwater-saltwater mixing zone of the estuary, except during its spawning season, when it migrates upstream to freshwater following winter “first flush” flow events (around March to May). It functions as an indicator species for the overall health of the Delta’s ecosystem.

Because of its one-year lifecycle and relatively low fecundity, it is very susceptible to changes in the environmental conditions of its native habitat. Efforts to protect the endangered fish from further decline have focused on limiting or modifying the large-scale pumping activities of state and federal water projects at the southern end of the estuary. However, these efforts have not prevented the species from becoming functionally extinct in the wild.

So lives in the brackish areas. To me, that says salt water intrusion further up the delta would give it more living space. It also clearly migrates, so would normally be expected to just migrate upstream a bit if the fresh / brackish interface moved.

Has “low fecundity”… so anything that competes with it could cause a load of problems. If a competitor in the same niche has just a few more offspring / cycle, it will eventually swamp them. Doesn’t sound like a water issue to me…

The delta smelt is one of five currently recognized species within the Hypomesus genus, which is part of the larger Osmeridae family of smelts. The genus has been subject to many revisions since it was first classified by Gill in 1863. The first major revision occurred in 1963, when the Osmeridae family was reexamined by Canadian ichthyologist Donald Evan McAllister. Expanding on Japanese researcher Hamada’s earlier determination that H. olidus was not a monolithic widespread species, but rather one of three distinct species of Hypomesus, McAllister assigned them new names, and further delineated what he believed were four subspecies. This was the first description of H. transpacificus; named for its supposed occurrence on both sides of the Pacific, and also “to the friendship of Japanese and Canadian ichthyologists.” He separated these geographically isolated populations into separate subspecies: H. t. transpacificus and H. t. nipponensis.

So it was thought to be one big species, then was thought to be 4 subspecies. Four fish so close to the same that it was hard for professional fish biologists to notice they were not one species. Ok…

Modern analysis of the genus would elevate all of McAllister’s subspecies to full species status, based on fin ray counts and the number of chromatophores between their mandibles, a change which genetic analysis has supported. In fact, genetic analysis would conclude that despite their morphological similarities, H. nipponensis and H. transpacificus are actually members of different phylogenetic clades.

The abbreviated distribution of Hypomesus species along both the east and west sides of the Pacific ocean suggests that their common ancestor had a range that would have crossed the Pacific. Researchers have hypothesized that climatic changes may have reduced the range of the ancestral species during cooling periods, which would have created a reproductive barrier, allowing speciation to occur. Although the low number of species in the genus and high levels of homoplasy have frustrated attempts to determine whether the northern Pacific H. olidus or H. nipponensis are the basal species of Hypomesus, it is known that the most recent speciation event in Hypomesus was between the two native east Pacific species, H. pretiosus and H. transpacificus. This is plausibly due to a geographic isolation of a widespread eastern Pacific ancestor, of which some members were isolated in a freshwater basin in western California, possibly in the lakes that would have been located in the southern San Joaquin Valley during the Pleistocene epoch.

Now we’re calling them all 4 full species… “This time for sure!”… This matters a bit further down… But for now, what about habitat?


The delta smelt is endemic to the Sacramento–San Joaquin River Delta in California, where it is distributed from the Suisun Bay upstream through the Delta in Contra Costa, Sacramento, San Joaquin, and Solano Counties. The delta smelt is a pelagic (lives in the open water column away from the bottom) and euryhaline species (tolerant of a wide salinity range). It has been collected from estuarine waters with salinities up to 14 parts per thousand.
Historically, delta smelt were distributed from San Pablo Bay upstream to Sacramento on the Sacramento River and Mossdale on the San Joaquin River, which varied seasonally and with freshwater outflow. Today, large areas of historic delta smelt habitat and designated critical habitat have become unsuitable for some life history stages of the species, even though key environmental characteristics (e.g. temperature, salinity, water depth) of these areas have not changed. Delta smelt disappeared from the southern portion of their historic habitat in the late 1970s, which coincides with substantial increases in the amounts of water exported from the Delta. It is likely that water export operations have a great effect on the distribution, abundance and genetic diversity of delta smelt.


The delta smelt is semelparous, living one year and dying after its first spawning. Delta smelt spawning occurs in spring in river channels and tidally influenced backwater sloughs upstream of the mixing zone where saltwater meets freshwater. The Sacramento and San Joaquin Rivers then transport the delta smelt larvae downstream to the mixing zone, normally located in the Suisun Bay. Young delta smelt then feed and grow in the mixing zone before starting their upstream spawning migration in late fall or early winter.

The delta smelt is preyed upon by larger fish, especially striped bass and largemouth bass, which are introduced species in the Sacramento-San Joaquin Delta.

So the entire argument over water comes down to a coincidental drop in “the late 1970s” when water projects opened (built, BTW, under Gov. Brown the elder…) and despite the statement that the key water quality indicators have not changed. Makes a fellow go Hmmmmmm…


Fishing for Black Bass

(Micropterus spp.)

Bass angling provides recreation and economic value to the state of California. For several years, California has been the center of attention for producing trophy-sized black bass. In a list of the top 25 largest largemouth bass caught in the U.S., 21 of the bass are from California waters. Nationwide attention to California ‘s largemouth bass fisheries began with the success of Florida largemouth bass introductions. Numerous catches of largemouth bass over 10 pounds were reported following the introductions and in 1972, the first largemouth bass over 20 pounds from California was caught at Lake Miramar. In addition to trophy-sized largemouth bass, the introduction of Alabama spotted bass in 1976 and subsequent introductions to other California waters has produced trophy-sized, and state and world record catches from California waters.
Largemouth bass, Micropterus salmoides, were first introduced into California from Quincy, Illinois, into Lake Cuyamaca ( San Diego County ) in 1891, and are now found throughout California. Two subspecies are recognized, the northern subspecies, M. s. salmoides, and the Florida subspecies, M. s. floridanus. The first introduction of Florida largemouth bass was made in 1959 into southern California. The value of Florida largemouth bass has been demonstrated by increased catches of trophy-sized fish and nationwide public attention. Many bass greater than 10 pounds have been caught from California waters including a 21 pound 12 ounce bass caught from Castaic Lake, Los Angeles County, in 1991.

So about 1960 they first come to Southern California. Then at some unclear later time get put in Northern California… if it were about 10 years, that would be about 1970… just in time to start snacking on smelt in the delta… and in 1976 we have a flood of Alabama spotted bass being introduced all over too.

The striped bass show up earlier, directly into the bay delta system, so have had more time to snack. Though it looks like they were not able to fully predate that smelt.


History of Striped Bass in California

There were originally no striped bass in California. They were introduced from the East Coast, where they are found from the Gulf of St. Lawrence to Alabama. The initial introduction took place in 1879, when 132 small bass were brought successfully to California by rail from the Navesink River in New Jersey and released near Martinez. Fish from this lot were caught within a year near Sausalito, Alameda, and Monterey, and others were caught occasionally at scattered places for several years afterwards. There was much concern by the Fish and Game Commission that such a small number of bass might fail to establish the species, so a second introduction of about 300 stripers was made in lower Suisun Bay in 1882.

In a few years, striped bass were being caught in California in large numbers. By 1889, a decade after the first lot of eastern fish had been released, bass were being sold in San Francisco markets. In another 10 years, the commercial net catch alone was averaging well over a million pounds a year. In 1935, however, all commercial fishing for striped bass was stopped in the belief that this would enhance the sport fishery.

I’d put my money on the large mouth bass as being the culprit. They are known to eat anything that moves, and are an ‘issue’ for many species when introduced into a water system. In any case, having one top predator added to your environment is bad, having two or three added is way bad. Then again, these are not called a ‘bait fish’ for nothing…

But there’s more…

When we look into one of those new “species” we find an interesting history…


Hypomesus nipponensis

The wakasagi, Hypomesus nipponensis, is an important food fish native to the lakes and estuaries of Hokkaido, Japan. It has been introduced in other locations, including the San Francisco Delta of the United States. It is raised in fisheries, and is very similar in appearance to the delta smelt (H. transpacificus).

Hmmm…. wonder why we never hear about the Japanese smelt… Is it dying out too? Has it reached the brink and does it need a flush of water to save it? One would expect that it, being nearly identical, might be subject to the same pressures of water issues.

Introduction to the United States

Native to the lakes and estuaries of Hokkaido, Japan and introduced to the lakes on Honshu and Kyushu, the Japanese wakasagi was introduced to California water reservoirs by the California Department of Fish and Game to provide more prey for stocked rainbow trout after failed attempts to introduce native delta smelt to three foothill reservoirs. At the time, the California-native delta smelt and the Japanese smelt were thought to be separated members of the same species, H. olidus. In 1959 the CDFG imported 3.6 million fertilized eggs attached to palm fiber mats from a population in Suwa Lake, located east of Tokyo; many of these eggs were dead on arrival. The fiber mats were placed in streams feeding into six lakes and reservoirs that appeared to be ecologically suitable for the smelt. It was thought at the time that these reservoirs could be chemically treated to eradicate the fish if they were found to be undesirable. In 1972 and 1973 about 77,000 fish from the Shastina Reservoir were moved to the Almanor Reservoir in Plumas County. All attempts to introduce the fish were successful, except the Dodge and Big Bear Reservoir introductions, the latter of which may have been partially attributable to chemical treatments meant to eradicate stunted crappie and goldfish.

Progression into delta

Although a retrospective analysis of preserved delta smelt samples caught in 1972 and 1982 from the Delta region has shown that wakasagi had been invading the estuaries in undetected quantities since at least the early 1970s, wakasagi expansion from these original introduction sites southward was not tracked until several years later. In 1994 they were detected at the State Water Project pumping plant for the first time, and by 1998 the fish could be found throughout the estuary including the Suisun and San Pablo Bays.

So these guys were more hardy and able to “make it” in lakes where the delta smelt could not. They are happy to live in fresh water, it seems. Then they progressed from the lake system, down the rivers, arriving in the Delta somewhere in the early ’70s and continued to spread out, eventually making it all the way over to where water is sucked off to Los Angeles and are now found “throughout the estuary” including the prime areas used by the delta smelt in Suisun and San Pablo bays.

Can you say “competition”? I knew you could…

So the native delta smelt gets a double whack of predation from fish introduced by The Government, then gets out competed by an imported cousin, introduced by The Government, and now The Government is saying flushing water out the bay will save it? What the???


Because the two species are very similar in morphology and life history, the wakasagi presents several potential threats to the endangered delta smelt. Besides direct competition for nutritional resources and the possibility that wakasagi may prey on the eggs and larvae of delta smelt, hybridization could either dilute the species or cause population decline due to sterilizing effects. In fact, a few hybrids have been captured in the wild, although all of them were first generation crosses and no evidence of back-crossing has been found, which would suggest that the hybrids were not viable.

Misidentification of the species is an additional concern, which could lead to inaccurate assessments critical to making policy decisions; however this problem may be mitigated if genetic markers are used for identification.

In addition to its negative effects on the delta smelt, the wakasagi significantly reduced Kokanee fisheries, but helped increase growth rates of other salmon and trout fisheries.

These Japanese versions of smelt are predators on the other smelt, but sometimes will swamp them in the mating dance as evidenced by the occasional crosses (either diluting their genetics, or just resulting in failed matings as the delta smelt choose non-productive paring with the more common competitor – guess they can’t tell it’s a different species or sub-species either ;-) and have also consumed eggs of Kokanee (red salmon in lakes) reducing them too.

So not only are the delta smelt being more heavily predated by bass, but by other smelt too, who sometimes get them mating without benefit, and are swamping them with competition for their niche, food, and space.

As these introduced smelt seem to be not having any problem with the water flow, tell me again how dumping fresh water is going to fix the problems faced by the Delta Smelt? I’d even go so far as to speculate that the Delta Smelt, being a known lover of brackish water, and the Japanese smelt, being called the “fresh water smelt” as that is what it prefers, having MORE salt water intrusion would be likely to favor the native Delta Smelt.

This paper finds much the same thing on competition:


(Though I can’t cut / paste from their PDF. Yeah, I know, I could break the copy protect,and on my tablet a different link that I can’t find anymore let me download it.. but…)

These folks too:


Means of Introduction: Wakasagi were intentionally introduced in 1959 from Japan by the California Department of Fish and Game as an experimental forage fish for trout (Wales 1962; Moyle 1976b; Dill and Cordone 1997).

Status: This species is established in several reservoirs and associated tributaries in California (Moyle 1976a; Shapovalov et al. 1981; Courtenay et al. 1986). It has not been recorded in Big Bear Lake since 1960 (Swift et al. 1993).

Impact of Introduction: This species has been found to negatively impact kokanee Oncorhynchus nerka and threadfin shad Dorosoma petenense (Dill and Cordone 1997). It also is known to hybridize with the native and federally endangered delta smelt Hypomesus transpacificus. Hybridization between the two species was suspected by Courtenay et al. (1986), and was later confirmed (Dill and Cordone 1997; Trenham et al. 1998).

Remarks: Dill and Cordone (1997) reviewed its introduction history in California. In documenting the original introduction, Wales (1962) incorrectly identified the species as Hypomesus olidus. Several authors (e.g., Moyle 1976a; Lee et al. 1980 et seq.) treated the introduced wakasagi as a subspecies of H. transpacificus (i.e., as H. t. nipponensis). In California the wakasagi is generally considered a freshwater species, hence its often-used name “freshwater smelt” in that state; however, it has recently been discovered in brackish waters, further threatening the continued survival of the imperiled delta smelt (Dill and Cordone 1997).

They have a nice map of where these guys have made a home in California:

Where the Japanese Smelt are living

Where the Japanese Smelt are living

So these guys are doing just fine, thanks.

Tell me again how flushing 1/3 of the available fresh water out the Gate is going to stop predation by bass and competition and genetic swamping by the Japanese smelt?

Frankly, it looks to me like a Government caused problem. A failed attempt at introduction of the Delta Smelt into lakes to spread it around, followed by an introduction of a stronger more dominant competitor that they failed to contain, along with introductions of a couple of top predator fish to make the sport fishing more interesting. In short, it is The Government that is driving this native smelt to extinction. Then flushing more fresh water out the bay just gives the introduced species an easier time of it in less brackish water. Sheesh. Can they do any worse?

At this point, IMHO, the best that can be done is to try to make a viable hybrid that can compete and have it replace the pure native. Rather like being done with Elm trees and Dutch Elm Disease. Or we could just admit that damn near nobody can tell the “invader” from the “native” and just let it take over the niche. All the predators will be happy to eat it, and nobody will really notice the difference in the delta. (In fresh waters it might reduce other fish, but we can’t stop that at this point anyway.) Perhaps we could find a place, like the Monterey Bay, where it is remote from the Japanese smelt populations but still has some brackish / fresh interfaces and establish a delta smelt population there. Maybe.

IMHO there is no justification at all for dumping loads of fresh water out the bay to “save” the Delta Smelt. Fresh water isn’t the problem, and might even be making things worse.

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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9 Responses to Drought, or Stupid Rescue Killing Delta Smelt?

  1. power grab says:

    Ding! Ding! Ding! We have a winnah!!

  2. Pingback: Drought, or Stupid Rescue Killing Delta Smelt? | Musings from the Chiefio | Standard Climate

  3. Adrian Vance says:

    Mr. Brown, a Jesuit turned liberal Democrat is clearly a conflicted man who does not realize species come and go. The Desert Smelt is likely an interim step, not meant to be permanent so the Federal government attempts to keep it alive in conflict with the force of Nature. Mother Nature is answering with a drought as she will not abide bad behavior. Mr. Brown appears not to understand the Gaia concept and like most liberals deny that man is involved. We have a place. It is our destiny to restore the atmosphere’s CO2 so green plants can thrive as they have in eons past. Denying us our destiny is another, more serious affront to Nature and the response appears to be a new ice age. Nature will freeze us out in the next 100 years. The people and cockroaches of Panama will inherit the Earth.

    Google “Two Minute Conservative” for clarity.

  4. E.M.Smith says:

    @Power Grab:

    We thank you for your support! ;-)

    @Adrian Vance:

    Um, I think you meant “Delta Smelt”.

    Also note that the present Gov. Brown is the Jesuit, while his dad, the elder Gov. Brown pushed for the water system to be built and was around when the fish introductions were happening. So son inherits from dad… and we owe the damage to both of them…

  5. Larry Ledwick says:

    I’m from the Government I am here to help!

  6. Many thanks for a very thoughtful and open minded analysis of a difficult problem. This type of error is happening over and over when first we introduce species to new habitats with not the slightest idea of what will happen (though many, many past expereinces should have been instructive). Then we assume that any change in species mix is a crime against nature and must be fought with all guns plazing, even though the vast majority of species that have ever lived are now extinct according to nature’s rules. There is very little evidence that we adequately understand the dynamic interaction of forces governing species’ survival and extinction nor do we know how to reliably manipulate those forces to achieve a desired outcome. In fact our understanding in this area (though massively exagerated in the minds of some academics and environmental managers) may be likened to our understanding of the dynamics of climate change, while our behaviour as a society suggests we will act in spite of ignorance because we “believe in the cause”.

  7. David A says:

    Good info, and mostly new information. As mentioned I live near the south fork of the Stanislaus, close to Pinecrest,, a PG&E lake. In talking to a near retirement PG&E employee, and his elderly father, I was told that many of the feeds to the delta, which now have reservoirs, used to run dry in the summer almost annually. Often, only due to reservoirs is it possible to keep the water flowing.

    The Pinecrest dam, like many, leaks, and the state will not allow these reservoirs to be repaired.
    It is a political game, but I am not certain what the objective is.

  8. Pingback: Raining Again in San Jose, In June, In A Drought | Musings from the Chiefio

  9. Dr. Mary Winfree says:

    I would like to add another contender or two for the cause of smelt decline
    (a) Infectious Hemorrhagic Necrosis Virus (also called Sacramento River Virus)
    (b) The shutting down of Harvey O. Banks pump – please take a look at the presentation because it shows, using the data provided by both Fish and Game and petition to declare the smelt endangered, the evidence that the smelt population increased for 20 years after the pump was turned on… I am afraid turning off the pump was the last blow to the smelt…

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