An attempt to restore the population of endangered Southern California steelhead trout living in the Santa Ynez River is being opposed by some jurisdictions that rely on the river and Cachuma Lake for their water supply. The number of trout, which travel to and from the ocean throughout their lifecycle, in the river began declining after the construction of Bradbury Dam on Cachuma Lake in 1953. Prior to construction, there were about 20,000 adult fish living in the Santa Ynez River, but with the dam limiting their ability to travel to and from the ocean, the population dropped to 100 adult fish by 1991, according to the State Water Resources Control Board.