A federal appeals court has largely upheld a 2008 plan that called for restrictions on water deliveries from California's Sacramento-San Joaquin Delta to protect a tiny, threatened fish.

The 9th Circuit Court of Appeals ruled 2-1 on Thursday that much of the U.S. Fish and Wildlife Service's 2008 biological opinion about the delta smelt was not arbitrary and capricious as a lower court judge had ruled.

The decision won't have any practical effect on water flows since protections for the smelt were kept in place while the lower court ruling was appealed.

Restrictions on water deliveries have spelled major losses for growers in the state's farm belt who rely on the Delta to irrigate crops.