The amount of water that 25 million Californians usually get from the Delta now depends on the fate of a tiny fish called "the Longfin Smelt."
State wildlife officials are deciding whether to declare the fish a "threatened or endangered species."
The difference in those two listings could mean trouble for water agencies all over the state.
It's a tiny creature -- barely two inches long but experts say California's Delta water supply depends on helping the Longfin Smelt fight extinction.
"It is used as a food source for other species native and non-native species in the Delta. But its mostly an indicator species of the health of the Delta itself," said John McCannon from California Fish and Game.
On Wednesday, the California Fish and Game Commission listened to testimony from water agencies, environmentalists and farm representatives.
The question before the commission was whether the Longfin Smelt's population decline over the past four to ten years is indicative of the deltas overall decline.
After seeing a bar graph showing the Longfin's population plummet, they voted unanimously to decide in the next year whether the Longfin should be listed as threatened or endangered.
"Now that the smelt is a candidate species that means that the commission is authorized to take measures to protect it. In this case were looking at emergency measures which will reduce the amount of water that can be diverted through those systems as a way to protect the population," said Kate Wing from the National Resource Defense Council.
The huge Delta pumps which send water all over the state but especially to millions of Bay Area users, have sucked in and killed a large population of the Longfin and its cousin the Delta Smelt, which is already protected.
The decline of the delta smelt already made officials reduce water from the Delta. The commission voted on Thursday to continue those restrictions to protect the Longfin.
"At this point it's too early to tell what that will mean for our delivery from the Delta but anything that happens in the Delta is a big deal to us because we get about 50-percent of our drinking water from the Delta," said Susan Siravo from the Santa Clara County Water District.
Water deliveries from the delta were also reduced because of last year's low rainfall. Even with recent rainfall many bay area water agencies are now relying more on their own reserves. The issue now is how to continue supplying their customers while saving the smelt.
"It makes it more and more difficult to get water out of the delta more restrictive, so while we may have some slack now that slack is narrowing," said Greg Gartrell from the Contra Costa County Water District.
California game fishermen say that the Longfin Smelt help feed game and commercial fish that migrate through the Delta each year. They feed a $3 billion dollar California industry.
"Commercial fisheries and salmon fisheries also depend on it as well. Without a good food web were not going to have healthy fisheries," said John Buettler.
