Two Nevada agencies are in court over a water rights decision that could have major implications for a state-run fish hatchery in rural Lyon County during times of drought. The Nevada Department of Wildlife has maintained a permit to pump 861.5 acre-feet of groundwater for its Mason Valley Fish Hatchery for decades, representing one of 13 permits that contributes about 15 percent of the facility’s water supply. The hatchery is north of Yerington, about 60 miles southeast of Carson City. Now, after its water rights permit was canceled and later reinstated by the state engineer’s office due to a lapse in paperwork, the wildlife department worries for its ability to produce tens of thousands of trout each year to stock bodies of water in western Nevada. That’s because the reinstatement came with a new priority date.…