Morain: Why the decline of this small fish is a concern

At the southern edge of the Delta, past a newly planted almond orchard, a vineyard and another young almond grove, 24 tanks are filled with roughly 400 tiny fish each, among the last of the Delta smelt.

A Delta smelt is no larger than your little finger. Its eyes look too large for its body, and it is translucent. It could be viewed as fragile, except that it had occupied the Suisun Marsh and Sacramento-San Joaquin Delta for about 10,000 years, before its population began crashing.

The U.S. Interior Department's decision to list the Delta smelt as threatened under the Endangered Species Act took effect 22 years ago today, April 5, 1993. Back then, there were perhaps 200,000 Delta smelt in the wild, down from 2 million 20 years earlier.

The Federal Register notice announcing the action said the species was 'primarily threatened by large freshwater exports from the Sacramento and San Joaquin river diversions for agriculture and urban use.' Other suspects included a drought, invasive species, a reduction of its favorite food, plankton, and chemicals from agriculture and industry. Not much has changed – except that farming has expanded and the population has grown – and smelt numbers have continued to dwindle.

Concluding that the situation had become more dire, the Interior Department declared the smelt endangered, meaning it faced extinction, in an order that took effect five years ago on April 7, 2010.

The Endangered Species Act signed by President Richard Nixon assumes humans can undo the damage they've done. It has worked for some creatures. Gray wolves and condors are back in the wild.

The Delta and its fisheries may be different. Millions of people and commerce worth billions of dollars depend on Delta water. Last month, scientists embarked on one of their periodic expeditions trawling for Delta smelt. They found four females and two males.

UC Davis fish biologist Peter B. Moyle pronounced that 'Delta smelt appear to (be) approaching the point of no return, with extinction in the wild possible in the next year or two.'

Moyle started sounding the alarm about Delta smelt in the 1980s after documenting sharp declines in the population. We met in 1991 when he was advocating that the feds move to protect the smelt. Maybe things would have turned out differently if they had acted more swiftly, maybe not.

He and I took a drive last week down to UC Davis' Fish Conservation and Culture Lab, a $2.5 million-a-year operation funded by the U.S. Bureau of Reclamation outside Byron at the southern end of the Delta. At 72, Moyle is contemplating semi-retirement by taking professor emeritus status, though he is not sure how that will work. He wears a baseball cap that has a Sacramento sucker with a mustache sewn onto it, not unlike the growth above his upper lip. He knows pretty much anything worth knowing about the Delta smelt.

They smell a little like cucumber. Why? Maybe it has to do with self-preservation. What self-respecting predator would want to eat something that smells like a cucumber? Fisheries professor humor.

What has happened to the smelt is a serious matter, however.

For the past 40 or 50 years, the fish has been buffeted by so much: the impact of dams, reservoirs, dredging and pumping that sends water south to farms and cities. It faced changes in saltwater flow from the bay and freshwater flow from the rivers, plus invasive species that eat its food, toxins from farms and urban use and, of course, the fourth year of the drought.

'It is hard to be optimistic,' Moyle told me. 'The populations are so low.'

The situation is complicated because the species has a one-year lifespan. If the smelt can't spawn successfully in one year, they won't be around next year, except for those that are in the fish tanks. At the Fish Conservation and Culture Lab, director Tien-Chieh Hung, director emeritus Joan Lindberg and their staff work to preserve the species. Imagine the difficulty of anesthetizing a tiny fish, inserting a tag under its skin, and sending a small clipping of its fin off to UC Davis for DNA typing to ensure genetic diversity.

They pair each male with the perfect female, and create the next generation. Each hatchling is the size of an eyelash. They're on their eighth generation now. 'This may be the last hope for the Delta smelt if my more pessimistic viewpoint is that they disappear from the wild,' Moyle said. 'This will be the last population.'

The goal is to keep the species alive until we — government, farmers, environmentalists, scientists, water users — figure out how to restore enough of the Delta that the fish can be reintroduced. Who knows how long that might take? 'It will only work if the conditions that support the species in the wild return as well,' Moyle said.

The Delta won't return to a state of nature any time soon. But various experts say sections of the Delta could be restored to something resembling a natural state, the notion of 'reconciliation ecology.'

In a report issued in April 2013, the Public Policy Institute of California said 'reconciled ecosystems can have the look, feel and function of natural systems — especially in terms of service provided — and these ecosystems can be managed to favor some organisms over others.'

Some people may shrug off the passing of the Delta smelt, and the next to succumb, perhaps the longfin smelt. We might care more when salmon, or green sturgeon, which can live for a century, die off. Some members of Congress cite the smelt as they argue that the Endangered Species Act be unraveled. That's no solution. It's capitulation.

Maybe only a handful of environmentalists and scientists will mourn the passing of the Delta smelt. But the issue goes beyond one species. The demise of the smelt tells us the estuary itself is imperiled. We are its stewards. We have an obligation to do what we can to save even the modest Delta smelt.

Dan Morain is editorial page editor and columnist for the Sacramento Bee.