The state says it needed the extension of its authorization so it can continue to manage a persistent problem at the locks. Each winter and spring, when adult steelhead return to the lake to spawn, they have been preyed on by a handful of California sea lions that congregate just downstream of a dam and a fish ladder situated at the locks. The season lasts from Jan. 1 to May 31 each year. Although Lake Washington steelhead once numbered more than 2,500 and supported tribal and sport fisheries, sea lions ate some 60 percent of returning adult steelhead during the late 1980s and early 1990s, and fisheries were closed. The steelhead population dwindled substantially into the early 1990s, reaching an all-time low of 70 spawners in 1994.
Biologists are cautiously optimistic, however, about more recent statistics.
Steelhead returns reached an estimated 610 spawning adults this season, the highest number since 1991. The federal Marine Mammal Protection Act was amended by Congress in 1994 to permit states to kill nuisance seals and sea lions that are hurting salmon and steelhead populations, under tightly controlled conditions that are specified in Letters of Authorization from the fisheries service.