Under the clear skies of an early autumn afternoon, windsurfers gripping brightly colored sails skim across glistening San Francisco Bay. For more than two decades, Bay Area environmentalists have labored to preserve their scenic waterway from a variety of environmental maladies. Yet despite some hard-won progress, the future of North America's largest West Coast estuary is not secure.
Danger signals appeared a decade ago when several species of local fish began showing population declines. The stripedbass population, for instance, is only 25 percent of what it was 20 years ago. The drop in bass is especially troublesome because the species is an ``indicator fish,'' used to gauge the health of the ecosystem made up of San Franciso Bay and the delta of the Sacramento and San Joaquin Rivers.
Another warning sign has been the appearance of toxic ``hot spots'' in the bay. In one recent instance, studies for a dredging project showed that tested bay sediment contained DDT levels among the highest levels ever recorded in California.
At a congressional hearing in the Bay Area this summer, biologists for the California Department of Fish and Game and the United States Fish and Wildlife Service testified that elevated levels of selenium (a chemical of the sulfur group) have been found in bay system ducks.
The San Francisco Bay Regional Water Quality Control Board, a state agency, recently held two hearings on its ``Basin Plan,'' the key document used to guide the board's decisions on permits for such activities as dredging and discharge of waste water into the bay.
First implemented in 1975 and scheduled for review every three years, the plan has been reviewed and revised only once, in 1982. Continued staffing shortages at the board delayed the current review by over a year.
A coalition of environmental groups -- including Citizens for a Better Environment (CBE), the Oceanic Society, the Environmental Defense Fund, and local chapters of the Audubon Society and the Sierra Club -- has formed a task force to fight for what some believe to be the bay's very survival. The effort focuses on freshwater inflow to the bay, control and treatment of toxic pollution, and protection of wildlife habitats.
According to CBE's Greg Karras, the task force believes that policy changes under discussion by the water-quality board show progress, notably in stricter dredging regulations and better definition and protection of wetlands.
The environmentalists also appreciate the Basin Plan's stance on water diversion and its recognition of the complexity of the issue, Mr. Karras said. For much of this century, water from Sierra-mountain rivers has been diverted to meet the growing demands of agricultural interests in California's Central Valley and a burgeoning population in the southern part of the state.
Today, 60 percent of the fresh water naturally destined for San Francisco Bay is rerouted southward by state and federal water projects. In the process rich estuarian breeding grounds and nurseries for marine fisheries are destroyed as the delicate balance of salt water and fresh is skewed.
Oceanographer Michael Rozengurt, a Russian 'emigr'e, says this process mirrors one he witnessed in his home country. Mr. Rozengurt studied the effects of the Soviet Union's diversion of fresh water away from the Black, Caspian, and Azov seas after World War II. He says he witnessed a catastrophic depletion of Russian fisheries.
He sees striking similarities in the California situation and cautions that it ``doesn't take 5,000 years, but only three, or five, or seven,'' to alter a marine ecosystem irrevocably.
Rozengurt is among experts who argue for the establishment of salinity and freshwater flow standards for San Francisco Bay. That position is echoed in the control board's draft plan and supported by environmentalists.
Next year the state Water Resources Control Board resumes hearings on who is entitled to the state's fresh water, particularly that from northern California. Environmentalists hope that with strong local backing, the regional board can ensure that water diversion takes place only if it does not harm the bay-delta ecosystem.