TOPPENISH, Wash. — Salmon may be the stars of the Northwest’s fish restoration efforts, but next week, the lesser-known lamprey will steal the spotlight in a film premiere at the Yakama Heritage Theater.

Pacific Lamprey are an ancient, eel-like fish species that migrate from rivers to the ocean and then return to freshwater to spawn. Lacking jaws, these parasitic fish feed in the ocean by attaching to other fish with their suckerlike mouths. The juveniles filter-feed in fresh water for several years before heading to sea.

Before dams were built, millions used to return to the Columbia Basin every year, but now the population is disappearing from most of its historic range. The lamprey struggle to swim up the dams’ fish ladders designed for salmon.

The film, “The Lost Fish,” follows efforts by the Columbia River tribes, including the Yakama Nation, to save the lamprey, which has both subsistence and cultural value to the tribal communities.

The Yakama screening will be at 6 p.m. Monday at the Heritage Theater, 100 Spiel-yi Loop, followed by a presentation by Yakama fisheries biologists. The film was produced by Freshwater Illustrated, an Oregon-based nonprofit conservation media organization, and the Columbia River Inter-Tribal Fish Commission.