User:CtopherL/Southern California Steelhead DPS

Lead
The Southern California Steelhead Distinct Population Segment (DPS) occurs from the Santa Maria River to the Tijuana River at the United States and Mexican Border in seasonally accessible rivers and streams. Steelhead (Oncorhynchus mykiss) in the Southern California Steelhead DPS, much like its relatives further north, requires sufficient flows in their natal streams to be able to return from oceans and lakes to spawn. Due to the extended periods of drought throughout their range, Southern California steelhead are most commonly seen during periods of increased rainfall, such as El Niño events. Declared federally endangered in 1997, the geographic range of the DPS when first listed extended from the Santa Maria River south to Malibu Creek. In 2002 steelhead were discovered in San Mateo Creek on the county line of Orange and San Diego counties. With this discovery the range of the DPS was extended to include Los Angeles, Orange, and San Diego counties.

Life History
Southern Steelhead have been observed as early as the late 19th century with many accounts recalling large schools of young salmon travelling up the mouths of the California rivers and streams. Sightings of this fish began to dwindle as the popularity of the fishery increased along with a volume of residents moving into Southern California seeking to develop the landscapes. Oncorhyncus mykiss runs would begin in the winter as California's wet season would bring strong storms pushing mud and varying sediments downstream to estuaries. As the water level of the freshwater systems rose, this mud would meet and mix in the ocean giving the cue for the trout to begin their journey upstream to their spawning grounds. As residency of Southern California increased, the landscape would have to be altered in order to accommodate for the homes that would have to be built and prevent damages. This included the construction of many concrete dams, gutters, ditches and systems of storm channels that would block and confuse O. mykiss as runoff was redirected. This includes dams such as the Matilijia and Rindge Dam in Ventura and Malibu as well as barriers along smaller streams such as the Trabuco Creek and Santa Margarita River. In addition, pumping of groundwater reduced the stream levels giving these fish a smaller window for estuaries to meet the ocean as well as a lesser chance to reach their natal waters upstream.