Citing a decline in ocean-dwelling fish, the California Department of Water Resources warned it will have to cut water deliveries to state water contractors another 10 percent, beginning in 2010.

The cutbacks are in addition to reductions that were announced in December 2008 because of the decline of the delta smelt, a 3-inch-long fish that lives in the Sacramento-San Joaquin River Delta, according to a news release.

The latest cutbacks are the result of a biological opinion issued by the Naitonal Marine Fisheries Service. They are designed to protect chinook salmon, steelhead and green sturgeon.

The service blamed changing weather conditons as well as significant ocean harvests for the salmon decline.

This year, about 370,000 acre-feet of water were diverted to meet the delta smelt biological opinion, An acre-foot—about 326,000 gallons—can meet the annual water needs of a family of four to five.

The State Water Contractors has challenged the biological opinion with a lawsuit, which is expected to be heard later this year. The group, which represents 27 water districts that purchase water from the State Water Project, contends the opinion is flawed and ignores scientific data, according to a news release.