Is There Any Hope for Delta Smelt?

Few delta smelt remain in the wild
Few delta smelt remain in the wild (Photo: University of California, Davis)

By Scott Hamilton, President, Hamilton Resource Economics

FIGURE 1. Average observed densities of delta smelt by life-stage and region. The numbers underneath the columns represent the average of the observed number of delta smelt per 10,000m3 of water sampled. “ns” indicates that no surveys were conducted for the given life stage in the given region. (California Fish and Game Journal 97(4):164-189; 2011, Figure 7)

Delta smelt have been protected under both the federal and state Endeared Species Acts since 1993. How have they fared with 28 years of protection? Their numbers are now less than one percent of the number at the time of listing. In order to assess status and trends, the fish are sampled in a number of surveys including the Fall Midwater Trawl (FMWT), a fish survey that samples around 80 locations each month from September through December. Delta smelt used to be abundant in the FMWT. During the last three years not one delta smelt has been captured in that trawl– that is, in nearly 1000 tries, delta smelt have not been observed.

Delta smelt are a small, delicate, native fish found only in the Sacramento-San Joaquin Delta. The number of factors contributing to their demise are numerous: lack of food, predation by non-native fish, loss of habitat, contaminants in their native waters, and entrainment at water diversion facilities.

And it is this last factor that has caused the fish’s name to be known by many farmers in the San Joaquin Valley. The state and federal water projects that supply water to the San Joaquin Valley and southern California have fish salvage facilities upstream of the pumping plants located in the south Delta. These facilities were designed to capture fish headed towards the pumps so that they could be relocated back into the Delta many miles away from the pumps. For a number of reasons, these facilities fail to protect delta smelt. The waters near the fish salvage facilities team with predators. Some of the most reliable estimates indicate that for every delta smelt salvaged at the pumps, thirty fall prey to predators. Also, the fish diversion facilities are not perfect; so, small fish may well pass through them. And finally, if any are salvaged, delta smelt are so delicate that most of them do not survive the capture, handling, transportation and relocation process.

When an otherwise lawful process, such as pumping water, harms endangered species, special permits called Incidental Take Permits are required to enable operations to continue. The regulatory agencies have the duty to protect the listed species and so, in approving the permit, they require project operations to be modified. Typically, this means reducing the quantity of water pumped when the fish are likely to be near the pumps. Delta smelt typically disperse from the northern regions of the Delta towards spawning grounds following the first big storm of the year. This brings a small proportion of adults, and then their offspring, within the vicinity of the pumps in the winter and spring (see Figure 1). Even though only a small proportion of the fish appear to be near the pumps, with so few delta smelt remaining, regulators are being cautious. Over time, the regulations to protect delta smelt and other listed fish has resulted in millions of acre feet less water being brought into the San Joaquin Valley–an impact felt by many farmers, particularly with the implementation of SGMA and another year of drought.

Were the regulatory agencies justified in imposing their protective measures? Did the measures have a population benefit? Were the measures based on the best available science? These questions have been the basis of several lawsuits and a number of scientific studies. There remains no definitive answer, and so the controversy and the fights continue. But as one attorney put it, what has been done has helped neither the fish nor the farmers.

Enter Paul Souza, the new regional director of the U.S. Fish and Wildlife Service. From his earliest days in Sacramento, he has been asking for a defensible list of the best actions that can be implemented to help delta smelt. Faced with massive loss of their native habitat, the management options for delta smelt are limited. Likely, any solution needs to be big and bold–implementing small, isolated projects is unlikely to reverse the population decline. But implementing big, bold and expensive restoration projects is a risky business many managers are unwilling to stick their neck out for. A number of stakeholders have now embarked on what is called a structured decision-making process, which is a commonsense approach to applying rigorous science in a collaborative framework to identify the best set of solutions. That work, funded largely by the water exporters, is underway. Due to the scientific complexity, the process will take several years to complete but, in the end, should give Souza his answers. In the meantime, Souza is not waiting. US Fish and Wildlife survive are developing a propagation program (a hatchery for delta smelt) to put tens of thousands of delta smelt back into the estuary. Whether they will get eaten by predators, starve, or flourish remains to be seen. But, if successful, there will likely be no benefit to the water supply. Pumping restrictions are unlikely to change for many years. Rather, a better method of diverting water is needed, one that does not harm the fish or attract them to predator filled waters (see Valley Voice, May 2021). The elusive goals of achieving both a self-sustaining delta smelt population and improved water supplies remains a long way off, but there are a large number of scientists and managers working behind the scenes to try to make that happen.

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