Plight of Delta Smelt Could Curb Water Flow : Environment: Endangered-species status for the tiny fish could force reductions in supplies from the Sacramento River Delta. The impact of such a designation could be enormous.

The delta smelt, a modest fish that once thrived in the murky waters of Suisun Bay, may succeed where environmentalists failed by forcing cuts in the amount of water taken from the Sacramento River Delta for delivery to farms and cities in California.

At a time when California’s water supply remains low, the U. S. Fish and Wildlife Service is scheduled to decide later this month whether the tiny delta smelt warrants protection under the Endangered Species Act.

Many environmentalists, biologists and water officials believe that, given the drop in the delta smelt’s population during the past decade, the federal government very likely will order the fish to be protected.

“If it’s not listed, it will be for political, not biological reasons,” said Peter B. Moyle, fisheries biologist at UC Davis, who initiated the drive to protect the fish after he found that its population plummeted from a high of 2 million in 1979 to about 200,000 now.

While the Sacramento River winter-run Chinook salmon already is protected under state and federal Endangered Species Acts, the delta smelt would be the first fish that spends its entire yearlong life in the Sacramento-San Joaquin River Delta to gain federal protection.

To protect the smelt, changes likely would have to be made in the way the delta itself is managed. Pumps in the southern delta that send water down State Water Project aqueducts may have to be turned down or off when the smelt spawn in late winter and early spring. Those pumps usually run full bore during these typically rainy months.

In the delta smelt, environmentalists believe they have found a “canary in the coal mine”--the living thing that succumbs first and sounds the alarm that the entire estuary is imperiled.

“It is fundamental to us,” said Bill Davoren of the Bay Institute, an environmental group in Sausalito that contends water exports are destroying the bay and delta. “If we can use the delta smelt to document it, we will.”

Given its potential impact, the delta smelt could take its place alongside a select few animals that, like the snail darter and spotted owl, attained notoriety for limiting human activity once they gained federal Endangered Species Act protection. The snail darter helped stopped construction of a dam in Tennessee; the northern spotted owl is forcing a halt to some logging in the ancient forests of Pacific Northwest.

The delta smelt grows to a length of no more than three inches. But in the view of Department of Water Resources Director David Kennedy, who is in charge of the State Water Project, those three inches measure up to an 800-pound gorilla.

With declining numbers of striped bass, sturgeon, salmon and other species found in the delta, the delta smelt only recently has attracted interest from anglers and environmentalists. One of two types of smelt in the delta, it is distinctive for its light blue hue, small mouth and odor that has been likened to a cucumber.

“In terms of the number of people affected, this is far bigger than the spotted owl and snail darter,” said Greg Wilkinson, lawyer for the state water contractors that buy from the State Water Project.

Water officials who oppose listing the smelt as endangered cite surveys showing their numbers may be rising. They also note that no biologist can say for sure why the fish began dying. But Moyle and some state Fish and Game biologists place water exports high on the list of reasons.

Even as the smelt’s future is contemplated, the Fish and Wildlife Service is considering other delta species for protection.

The winter-run Chinook salmon, which passes through the delta on its way to spawn in the Sacramento River system, already is listed as a “threatened” species under the federal Endangered Species Act. The California-Nevada Chapter of the American Society of Fisheries is asking that the Chinook be given even more protection as an “endangered” species. Such a designation could require additional releases from reservoirs during spawning season in the early winter.

At the same time, the U. S. Environmental Protection Agency is formulating a management plan to protect San Francisco Bay and the Sacramento-San Joaquin River Delta.

Taken together, actions being contemplated for the largest estuary on the West Coast of North America amount to fair warning that the delta and bay will be given greater protection in coming years at the expense of water exports.

“I’m hopeful that we will look at different mechanisms rather than just stopping the flow south,” said Michael Gage, president of the Los Angeles Department of Water and Power board of commissioners.

A federal declaration that the smelt is threatened with extinction would be “a direct blow at the water project’s expectations--as well it should be,” Davoren said. For too long, he said, “they’ve been taking too much water.”

The effort to put the delta smelt on the endangered species list began in the relatively calm and shallow inlet of Suisun Bay, east of San Francisco Bay. In years past, Suisun Bay was the site of what biologists call the “mixing zone,” where fresh water meets salt water from San Francisco Bay. Delta smelt seek out the mixing zone because the zooplankton they eat is plentiful there.

In 1979, when UC Davis biologists began taking a fish census there, Suisun Bay was especially lush. There were perhaps 2 million delta smelt. But for some reason, starting in 1980, the number fell. Since 1985, the Davis team has found only a half dozen delta smelt in Suisun, leading to Moyle’s estimate that there are 100,000 to 200,000 in the delta today.

“That is what got my interest: where did this fish go?” said Bruce Herbold, a fisheries biologist who headed UC Davis’ Suisun Bay fish project.

One day in 1988, as he punched numbers supplied by the state into his computer, Herbold came to a startling realization. So much water was being sucked through the State Water Project pumps that the San Joaquin River flowed uphill not just during the dry summer, but in wet winter and spring months when the delta smelt spawn and their eggs hatch.

“ ‘Oh,’ ” he said, recalling his reaction, “ ‘this is what is hitting delta smelt on the head.’ ”

The mixing zone, as Herbold and others have found, drifts depending on the amount of fresh water allowed to flow into the delta. As more river water flows toward the bay, the mixing zone moves west and settles in Suisun Bay.

But because of the large amount of fresh water pulled into the pumps during recent drought years, the mixing zone has shifted southeast to the deeper and faster-moving Sacramento River channel. A reason for the loss of delta smelt may be that stronger currents have pushed them into the bay.

Armed with evidence of a smelt population crash, Herbold and his mentor, Moyle, set out to persuade governmental agencies that the once abundant delta smelt needed protection.

The first stop was the state Department of Fish and Game. State biologists responded by citing their work, and recommending that the state Fish and Game Commission declare the delta smelt to be a threatened species.

Like the federal designation, a finding by the state that a species is “threatened” means that it may become endangered in the foreseeable future. A designation of “endangered” means an animal could become extinct within a few generations.

The state Fish and Game report said water pumping may have drained the delta smelt population, but also suggested that disease or parasites may have caused the die-off. Pumps used to irrigate delta islands where farmers tend crops may be culprits, too. Another theory is that a rapidly reproducing type of clam accidentally released into the delta is consuming the smelt’s favorite type of plankton.

After a heated meeting last August, the Fish and Game Commission, noting that the cause of the decline remained unclear, ordered more studies. But as those studies continue, the American Fisheries Society, also relying on Moyle and Herbold’s work, pressed its petition to the U. S. Fish and Wildlife Service for federal protection of the smelt. A recommendation is expected on June 29.

“We can’t do anything other than assume it will be listed,” Dick Clemmer, the Metropolitan Water District’s manager of San Francisco Bay-Delta affairs. “Like national defense, you can’t wait until you get bombed at Pearl Harbor to prepare an army.”

State and local officials say they already are pressuring the Fish and Wildlife Service to reject the listing. If the service recommends that the delta smelt be protected, lobbying will focus on Interior Secretary Manuel Lujan Jr., who must make the final decision.

Clemmer said the state water contractors, an organization of local agencies including MWD and some San Francisco Bay Area agencies that are State Water Project customers, have authorized a lawsuit against the Fish and Wildlife Service to gain access to internal papers on which it bases its decision.

“We are going to try to influence the decision,” Clemmer said. “We firmly believe there isn’t enough information to call for a listing.”

Protection for the delta smelt could affect water operations in much of the year, water industry experts say. Clemmer envisions scenarios where the MWD, which supplies 15 million Southern California customers, would have 25% shortages even in wet years--”and not very good prospects of being able to do anything about it.”

The listing could require that less water be pumped during the delta smelt spawning season between February and May. As it is, State Water Project operators generally run pumps at maximum capacity--12,800 acre-feet per day--during these months when rivers are swollen by rainfall and early Sierra snowmelt.

State and federal water project operators already have restricted pumping to protect striped bass in May, June and July. Additional flow restrictions on the Sacramento River may be in store to ensure survival of winter-run Chinook.

“We’re going to get to the point where you can only operate the pumps for a month or two,” said Randy Brown, a Department of Water Resources fisheries biologist. Brown, who opposes putting the delta smelt on the endangered species list, estimates the smelt population at 300,000 and says the species is showing signs of increasing.

“My view is that this guy is pretty tough,” Brown said. “He has learned to adapt. Given some good flows and more normal conditions, if we can ever get those, then the animal should rebound.”