SACRAMENTO, Calif. (AP) — It was just five years ago that fishing guide Bob Sparre had all the salmon he could handle. He brought beaming clients back to shore loaded with prized Chinook salmon after a morning trolling the rivers and channels of the Sacramento-San Joaquin Delta in northern California.

On a recent day, heading out on the Sacramento River amid a chilly, mid-winter fog, the guide of 20 years couldn’t catch even a single fish for his lone client.

It was the kind of unproductive and unhappy trip that he and other guides say has become all too common in recent years, as the populations of salmon and other fish in the delta have plummeted. The number of fall-run Chinook salmon returning to the Central Valley to spawn has declined from more than 750,000 in 2002 to 66,000 in 2008.

“The numbers are getting scary,” he said. “At this rate, it doesn’t look like we will have a fishery if it continues the way it’s going.”

The perilously low populations of salmon and native fish are symptoms, according to numerous scientists, of a crashing ecosystem in the West Coast’s largest estuary. Numerous theories abound for the decline, from too much water being pumped from the delta for drinking and irrigation to the use of agricultural chemicals.

Whatever the cause, Gov. Arnold Schwarzenegger and state lawmakers believe they took a step to restoring the delta when they passed policy reforms last November and approved an $11 billion water bond to go on the November ballot. Schwarzenegger said it would launch the nation’s largest environmental restoration project since the federal effort to save the Florida Everglades.

“Now the hard part begins, and it’s going to be a real effort to restore the delta and bring that certainty back to water supplies,” said Sue Sims, chief deputy director of the state Department of Water Resources.

Sprawling across a region about the size of Rhode Island, the delta is the heart of the state’s water-delivery system and supplies drinking water to some 25 million Californians and irrigation water to thousands of farms. Rivers that drain from the northern Sierra Nevada meet in the delta before emptying in San Francisco Bay.

In recent years, federal courts and the U.S. Fish and Wildlife Service have restricted pumping from the delta to protect fish. Among those rulings was a 2007 court directive to cut pumping, a decision that contributed to thousands of acres of agricultural land being fallowed and new pumping limits.

Making matters worse, a three-year drought also has limited the amount of fresh water that passes through the delta.

The legislation’s two main objectives are to increase the reliability of water deliveries and to restore the ecosystem for plants, animals and fish. Under the measure, a council will develop a management plan for the estuary, new statewide conservation and groundwater monitoring mandates will be implemented, and penalties for those who fail to report water diversions will be increased.

The bond measure would provide some of the funding that will be needed over the next decade for delta restoration, dams and underground water storage, water recycling and cleanup projects.

Critics say the bills fall short in several key areas:

— The Delta Stewardship Council, to be formed this year, lacks the clout it needs to implement change. For example, major decisions about wildlife habitat and water pumping still need to be approved by state and federal agencies that often have competing priorities.

— The state Water Resources Control Board will determine how much freshwater ought to flow into the delta, but it will not be required to follow its own guidelines when reviewing permits to divert water.

— The legislation fails to identify ongoing funding for the delta council, restoration efforts, a new science panel and enforcement of the state’s water laws. The $11.1 billion bond before voters would provide only a portion of the money needed.

Scientists, fishermen, environmentalists and some lawmakers long involved in California’s water disputes question whether the environmental problems can be solved under those circumstances. They note that state lawmakers and Congress have devoted billions of dollars to restoring the delta and improving water transfers over the years with little to show.

“There are a lot of grand ideas and a lot of things that don’t seem to have a lot of authority behind them,” said Peter Moyle, a fish biologist at the University of California, Davis.

Farmers and some delta residents also say the delta will never recover until tough guidelines are implemented to guarantee how much river water must continue flowing through it — a way to ensure that pumping does not deprive the estuary of the freshwater it needs.

That’s been a thorny issue for years as water agencies dependent on delta exports are eager to protect the water they have traditionally received.

“Just throwing money at something isn’t going to do it,” said Zeke Grader, executive director of the Pacific Coast Federation of Fishermen’s Associations. “They could give us a trillion dollars and it’s not going to restore the fish unless there’s water for them at the right times and then that it’s good quality water.”

Supporters of the legislation emphasize that it was not intended to solve all the state’s water problems or repair the delta overnight. But they also say more needs to be done.

For example, the state, delta residents, water and wildlife agencies, farm interests and environmental groups need to agree about how the delta is used in the future — how much land is set aside for flood bypasses, as habitat for native species, and for farming and housing.

“We’re going to have to set targets for what we want to do to save the delta ecosystem, and we’re not there yet,” said Gary Bobker, director of the delta program for the Bay Institute, which is based in Novato, north of San Francisco.