Southern Steelhead
Steelhead in Topanga Creek. Photo by Sabrina Drill
Southern steelhead trout (
Oncorhynchus mykiss) make up a distinct population of a wide ranging species that includes both steelhead and rainbow trout. While rainbow trout stay in freshwater streams and rivers throughout their lives, steelhead are anadramous - meaning that like other species in their family that are known as salmon, steelhead spend part of their adult lives living in the ocean.
A juvenile steelhead "smolt" in Topanaga Creek. Photo by S. Drill
The portion of the worldwide population known as southern steelhead live in streams from the Santa Maria River in Santa Barbara County down to the Tijuana River on the US/Mexico border. This segment of the species was declared federally endangered in 1997.They used to occur in streams and rivers throughout Ventura and LA Counties. Now, they are known from the Ventura and Santa Clara Rivers, as well as in Malibu Creek and other streams in the Santa Monica Mountains. There are land-locked populations of rainbow trout in the upper San Gabriel River above dams that are thought to have descended from anadramous steelhead.
Rindge Dam on Malibu Creek. Photo from the Southern California Wetlands Recovery Project
Dam construction, channelization, and other forms of river engineering ( known as "hydromodification") are some of the most important factors affecting steelhead, as they can cut off access to the ocean. Other factors include water pollution, increased water temperature, introduction of exotic fish species, and changes in food availability in both streams and the ocean.
Watershed Restoration and Dam Removal Projects
Dr. Drill has served as a researcher and technical expert on several efforts to restore watersheds, and remove large dams, throughout Ventura and Los Angeles Counties
Ecosystem/steelhead friendly ways to restore fire and debris flow affected watersheds in Santa Barbara and Ventura Counties:
Smith, Stacie; Gomez, Mauricio; White, Jason; Boyd, Lea; Dagit, Rosi; Drill, Sabrina; Hirsch, Regina; Robinson, Tim. (2018). Fire and Flow Forum Strategic Plan: A Stakeholder Response to Rising Climatic Threats in Southern California Watersheds. South Coast Habitat Restoration and National Marine Fisheries Service. 23.
Restoration of ecosystems and fish passage by removing large dams:
Malibu Creek Ecosystem Restoration/Rindge Dam Removal, led by California State Parks
Matilija Creek/Ventura River Ecosystem Restoration/Matilija Dam Removal, led by Ventura County
