21,000 fish die in ‘catastrophic failure’ at UC Davis facility. Here’s the suspected cause

An estimated 21,000 fish died at the U.C. Davis Center for Aquatic Biology and Aquaculture in what the university described as a “catastrophic failure.”

The loss appears to be a result of chlorine exposure, to which fish are uniquely sensitive, according to a Thursday news release from U.C. Davis.

U.C. Davis has initiated an independent external review to determine where their systems failed and potential risks at similar facilities.

“We know that many researchers, regulatory agencies, Native American tribes and other partners trust us to care for their aquatic species,” the release read. “We will work hard to earn that trust by conducting a thorough review of our facilities, holding ourselves accountable for what happened, and taking steps to prevent it from happening ever again.”

The Center for Aquatic Biology and Aquaculture, or CABA, is a 5-acre facility that houses a range of aquatic biology programs, according to the center’s website. About 15 species are typically under study in the facility at any time.

At the time of the incident, researchers were conducting an investigation of environmental stressors on fish species including green and white sturgeon and the endangered Chinook salmon.

U.C. Davis conducts aquatic research at many other facilities, according to the release. The university will evaluate risk at facilities with similar potential for chlorine exposure.

CABA is now in the process of notifying regulatory and funding agencies of the loss, as well as developing mitigation plans for directly affected research programs. The university also committed to caring for the surviving fish and supporting grieving students, staff and faculty.

“We share the grief of the faculty, staff and students who worked to care for, study and conserve these animals,” the release read. “The people who conduct and support the research at this facility are conservationists, ecologists and veterinarians whose life work is devoted to understanding and supporting these species. We recognize that this loss is particularly devastating to our community.”