USGS Science Helps Agencies Create Conservation Plan for Santa Ana River, Native Fishes

San Bernardino, Calif. – The U.S. Geological Survey is playing a role in providing the science being used by agencies to manage the habitat for two threatened California fish species – the Santa Ana Sucker and the Arroyo Chub. Both species, which live in the Santa Ana River Watershed, are of special interest to local, state and federal agencies desiring to protect the fishes’ fragile ecosystem.

Two USGS California Water Science Center studies, cooperatively funded by the San Bernardino Valley Municipal Water District, will provide necessary data that will help agencies establish a Habitat Conservation Plan designed to protect the river, the habitat and the native fishes living there.

The Santa Ana Sucker is recognized federally as a threatened species, while state authorities recognize the Arroyo Chub as a species of special concern. The goals of the HCP are to enable the water resource agencies to provide a reliable water supply for human uses; maintain natural rivers and streams that provide habitat for rare species; and maintain recreational opportunities for activities such as hiking, fishing and wildlife viewing. The agencies will design the plan to specify how species and their habitats will be protected and managed in the future.

In order to develop an HCP for the upper Santa Ana River, agencies need sufficient knowledge of the populations and food sources of native fishes in the watershed. Since September 2015, the USGS has been studying the fish populations in this habitat, providing population estimates and helping create a habitat suitability model for the Santa Ana River native fishes. 

USGS scientists have been collecting new data on sediment transport and the physical characteristics of the river reach currently occupied by the native fishes. The sediment dynamics of the river have a large influence on the Santa Ana Sucker, which rely on coarse material like gravel and cobble for their primary food of diatoms and algae. Arroyo Chub is a much more generalized species that can be found in a wide range of conditions. These valuable data allow agencies to evaluate expected habitat quality throughout the river, and make informed decisions when establishing a HCP.

A description of the USGS project, “Native Fish Populations and Habitat Study, Santa Ana River, California” is available online. To learn more about USGS Water Science, please visit the USGS Water Resources of the United States website or the USGS California Water Science Center website.