Adapted to the boom-and-bust flood cycles of Southern California's rivers, the Santa Ana sucker now finds itself smack in the middle of one of the most urbanized places in North America. With its river homes tamed, dammed, channelized and enveloped by Los Angeles and the sprawl of the Inland Empire, this little fish requires clean water to survive. Its precipitous decline is a prime indicator of the health of Southern California watersheds.

The Center has repeatedly engaged in litigation to compel the U.S. Fish and Wildlife Service to designate critical habitat for the Santa Ana sucker. The agency initially granted 21,000 acres but later slashed this number, excluding habitat in the Santa Ana basin, when it decided the impacts to developers warranted removal of protections. The Center filed suit against the Service in 2007 to force it to designate adequate critical habitat, and in 2010, the agency protected a total of 9,331 acres, including the fish's namesake river, the Santa Ana. When that critical habitat was threatened by Southern California water agencies and towns, the Center and allies intervened in November 2011, and a judge upheld the fish's habitat protections.

The massive Seven Oaks Dam, a flood-control dam on the Santa Ana River, severely damaged the habitat of the Santa Ana sucker and other rare species when it was constructed, eliminating the boom-and-bust hydrology of this river's flashy hydrologic system. The Center actively opposed the dam and is still working for habitat renewal, fish reintroduction, and ultimately dam removal. In July 2016, in partnership with Endangered Habitats League, we announced our intent to sue the U.S. Army Corps of Engineers for its failure to assess harm to Santa Ana suckers regarding the effects of its management of Santa Ana River flood-control projects, including operation of the Seven Oaks Dam.Just a month later we(with two partners) filed another notice of intent to sue the cities of Colton and San Bernardino and their regional wastewater reclamation authority for illegally killing federally protected Santa Ana sucker fish by halting water releases critical to maintaining surface flows of the Santa Ana River.

Our efforts to protect the Santa Ana sucker are part of a larger campaign to restore Southern California watersheds for the benefit of the Pacific lamprey, unarmored three-spined stickleback, southwestern willow flycatcher, yellow-billed cuckoo, arroyo toad and dozens of other imperiled species.