Santa Ana River Native Fish Population and Habitat Data, Santa Ana River, California, 2023

Publication Date

2024-06-11

Start Date

2023-09-01

End Date

2023-10-11

Wulff, M.L., Huntsman, B.M., Buxton, J.M., and Gronemyer, J.L., 2024, Santa Ana River Native Fish Population and Habitat Data, Santa Ana River, California, 2023: U.S. Geological Survey data release, https://doi.org/10.5066/P1VWNREO.

Collection of additional data on the Santa Ana Sucker and the Arroyo Chub has been identified as a needed task to support development of the upper Santa Ana River Habitat Conservation Plan (HCP; http://www.uppersarhcp.com). The ability to monitor population abundance and understanding the habitats used by species are important when developing such plans. The Santa Ana Sucker is listed as a threatened species under federal legislation and is considered a species of special concern in California by the California Department of Fish and Wildlife (Moyle, 2002). The Arroyo Chub is also considered a species of special concern in California by the California Department of Fish and Wildlife (Moyle, 2002). Both species are present in the Santa Ana River watershed in the area being evaluated for establishment of the upper Santa Ana River Habitat Conservation Plan. The HCP is a collaborative effort involving the water resource agencies of the Santa Ana River Watershed, the US Fish and Wildlife Service, California Department of Fish and Wildlife, and other government agencies and stakeholder organizations. The goals of the HCP are to: 1) enable the water resource agencies to provide a reliable water supply for human uses; 2) conserve and maintain natural rivers and streams that provide habitat for a diversity of unique and rare species; and 3) maintain recreational opportunities for activities such as hiking, fishing, and wildlife viewing, provided by the protection of these habitats and the river systems they depend on. The HCP will specify how species and their habitats will be protected and managed in the future and will provide the incidental take permits needed by the water resource agencies under the federal and state endangered species acts to maintain, operate, and improve their water resource infrastructure. Although the Santa Ana Sucker has been the subject of various research and monitoring studies within its remaining habitat in California, initial assessment of the available data within the HCP suggested that additional data on population size, fish habitat use, and availability of suitable habitat would be needed to support development of the HCP. Similarly, work on the Arroyo Chub has been limited and there is little data on the species within the HCP area, particularly the mainstem Santa Ana River. Thus, the collection of additional data on these two species has been identified as a needed task to support development of the HCP. The goals of the current study are: 1) Compare snorkeling and electrofishing as methods for estimating native fish abundance; 2) Develop a population estimate for native fish species in the study area based on the results from Goal 1, and 3) Develop a habitat suitability model for the Santa Ana River for Santa Ana Sucker, and if possible, Arroyo Chub.

• USGS Data Release Products