typical of the creek water. Aside from carp, several other native and introduced fish species were found in the creek until the 1980s, including mosquito fish, bluegill, bass, and channel catfish. After flooding exacerbated by urban runoff destroyed much of the remaining riparian habitat, these species were reported to have disappeared from the area. The historical presence of endangered steelhead trout (Oncorhynchus mykiss) in Aliso Creek has been debated. Until 2006 the National Marine Fisheries Service (NMFS) stated that there was "no evidence of historical or extant of O. mykiss in anadromous waters" in Aliso Creek. However, a 1998 study co-authored by the U.S. Army Corps of Engineers and US Fish & Wildlife Service declared that steelhead had inhabited the creek until the 1970s, when increased urbanization resulted in poor water quality conditions (pollution and low oxygen levels) that drove the migrational fish out. In 2009, after years of petitioning from local residents and environmental groups including Friends of the Aliso Creek Steelhead and Clean Water Now, the NMFS recognized the lower of Aliso Creek as former steelhead habitat and the creek was added to the Distinct Population Segment List under the jurisdictional domain of NOAA. It is now considered a candidate for re-colonization. The evidence cited included Native American (Acjachemen) accounts of takings, as well as anglers who reported taking steelhead trout in the 1960s and 1970s from Aliso Creek's estuary and Aliso Canyon before suburban development began. The last reported observation of steelhead in Aliso Creek was in 1972. In the 1970s, a large population of the threatened tidewater goby (10,000–15,000) was documented in the Aliso Creek estuary. The species has declined significantly since then due to pollution and reduction of its habitat. In 2011 the U.S. Fish and Wildlife Service designated the Aliso Creek estuary and several other coastal Southern California streams as critical habitat for the tidewater goby. History First inhabitants Aliso Creek historically served as a boundary between the Tongva Native Americans in the north, and the Acjachemen (sometimes grouped with the larger Payómkawichum) in the south. The Tongva's territory extended north, past the Santa Ana River and San Gabriel River, into present-day Los Angeles County, while the Acjachemen's smaller territory extended from Aliso Creek south, past San Juan Creek, and to the vicinity of San Mateo Creek in present-day San Diego County. The availability of perennial water in some parts of the creek made