killer whales
© Sandra Cannon/Associated Press Lack of food caused in part by the effect of dams and other man-made obstacles on California rivers and streams that are diminishing food sources for killer whales has become a greater threat to the whales' survival.

Federal wildlife officials have concluded that killer whales are threatened by California's massive network of dams and water diversions, a development that could bring a massive shift in public opinion about the state's water issues.

Though the iconic orca never ventures into freshwater, its primary food source does. Salmon species in the Central Valley are in bad shape, in large part due to the damming and diversion of their habitat on numerous rivers in California's interior. Their decline threatens to starve the dwindling southern resident population of killer whale, which numbers less than 90 animals.

As a result, the National Marine Fisheries Service has concluded that California water operations may jeopardize this killer whale population. The decision is contained in a draft biological opinion being prepared on Central Valley salmon and sturgeon species in response to a court order. It has not yet been publicly released, but is due to be presented in federal court by March 2.

The charismatic orca has its home waters in Puget Sound but ranges from Alaska to Monterey. However, in recent years it has been seen more often in California waters.

It is not yet clear what the decision on killer whales will mean for California's water supply challenges. But Zeke Grader, executive director of the Pacific Coast Federal of Fishermen's Associations, said it's a reminder that water management in the state has effects far beyond a single river or species.

"It's not just one obscure little fish anymore," he said. "I think it may very well bring home to people that we've got to be concerned with the whole system."