Farming and industry groups in Washington state sued to remove Puget Sound's several dozen killer whales from the endangered species list, saying the designation will result in unnecessary water and land-use restrictions.

The listing, issued by the National Marine Fisheries Service in November, will result in "needless" restrictions on the state's farms, especially those near rivers inhabited by salmon — the orcas' prime food source — the groups wrote in the federal lawsuit filed Monday.

"Farmers could face fines and even imprisonment for the most basic farm practices should such actions allegedly disturb salmon," the lawsuit reads.

Environmentalists described that scenario as far-fetched, although deliberately harassing a protected species does carry a year in jail.

Orcas — the type of black and white whale featured in the film "Free Willy" — can grow to 30 feet long and weigh 10 tons.

Three orca pods, or families, live in western Washington's inland waters from late spring to early fall. They total 89 whales, up from a low of 79 in 2002 but down from historical levels of 140 or more.

Lawyers for the Farm Bureau and the Building Industry Association argue that those orcas do not meet the technical requirements for protection under the Endangered Species Act because they are not a "distinct population" of the species.

While the entire subspecies known as "Northern Pacific resident orcas" could be listed as endangered, they argue, the Puget Sound pods alone may not. The subspecies also includes orcas off Alaska and Russia.

Environmentalists scoffed at the argument.

Patti Goldman, an attorney for the environmental group Earthjustice, said that is like saying the Puget Sound orcas gave up their membership in the species when they were named part of the subspecies.

She also said the Endangered Species Act defines "species" as "any subspecies of fish or wildlife or plants."

Russell C. Brooks of the Pacific Legal Foundation, representing the farmers and builders, said they are not against orcas, they just want the fisheries service to follow the letter of the law.

Pollution and a decline in prey are believed to be the whales' biggest threats, although stress from whale-watch boats and underwater sonar tests by the Navy are also concerns.