Wednesday April 2, 2025
USGS —
The Santa Ana Sucker (SAS) is listed as threatened under the U.S. Endangered Species Act. The Act protects and aims to recover endangered species and their habitats. To support this goal, USGS scientists are researching what is necessary to restore and sustain healthy fish populations.
Current USGS research on the SAS began in 2015 when the San Bernardino Valley Municipal Water District partnered with the USGS to conduct a native fish survey. The goal of the survey was to estimate native fish species abundance within a chosen section of the Santa Ana River designated as critical habitat. In addition to the SAS, the Arroyo Chub (Gila orcutti) was also studied. This was done in support of the Upper Santa Ana River Habitat Conservation Plan.
At the start of the survey, sampling methods included beach seining (netting) and snorkeling. Now backpack electrofishing is used exclusively. However, seasonal sampling constraints related to the fish’s spawning cycle, as well as inconsistencies in methods, resulted in a limited understanding of fish population dynamics. As a result, there was a need for alternative, less intrusive sampling methods.
Recently, USGS researchers investigated the potential for passive integrated transponder tagging (or “PIT tagging”) to be used to identify individual fish and track their movements.