Washington farmers have asked a federal judge to order the National Marine Fisheries Service to retract its claim that repairing a Skagit Delta tide gate could cause Puget Sound salmon and killer whales to go extinct.

Skagit County Dike District 12 submitted the motion Friday to U.S. District Judge Brian Tsuchida in Seattle, seeking to overturn NMFS’s finding, which blocks repairs to a tide gate protecting about 200 acres of farmland.

The district argues NMFS ignored precedent and defied logic in maintaining that repairing the 140-year-old tide gate would jeopardize the continued existence of salmon and killer whales throughout Puget Sound.

“The project does not convert any marine wetlands to agricultural land,” the motion reads. “That previously occurred 140 years ago when (the area) was first diked.”

District 12 is seeking a federal permit to repair a storm-damaged tide gate at the mouth of No Name Slough, which empties into Padilla Bay, about 70 miles north of Seattle.

The tide gate deprives salmon of habitat, according NMFS. If the district makes repairs, the tide gate will last for another 50 years, continuing its harm to salmon and killer whales, which eat salmon, according to NMFS.

NMFS has given the district the option of spending million of dollars on fish restoration in the Skagit Delta to make up for maintaining the tide gate. The district says that is not a practical option.

NMFS’s position sets a precedent for other tide gate projects in the 70,000-acre delta. Diking districts maintain more than 100 tide gates to keep Puget Sound saltwater tides from flowing onto farmland.

In its motion for summary judgment, District 12 argues NMFS misapplied the Endangered Species Act by treating the tide gate as a new structure, rather than something that’s been on the landscape since the 1800s.

The district also argues that even if the tide gate were gone, the farmland it protects would not become fish habitat. A jetty blocks Skagit River juvenile salmon from reaching Padilla Bay, according to the district.

The Swinomish Indian Tribal Community has moved to intervene in the lawsuit on NMFS’s side. The judge has yet to rule on the tribe’s motion.

The tribe argues that federal agencies have been too quick to allow tide gate repairs without requiring districts to invest in fish restoration.