Report on Mass Fish Death Released

An independent investigation has found that a catastrophic fish mortality event at the UC Davis Center for Aquatic Biology and Aquaculture in August 2022 was caused by accumulation of mineral deposits inside sealed piping carrying wastewater away from the facility. This blockage caused chlorine, added to effluent water as a disinfectant, to back up to a water line used to lubricate pumps at the well supplying the fish tanks, and thus contaminate the tanks.

There was no forewarning of the problem and no individual or group of individuals can be singled out as responsible, wrote Anthony Farrell, professor emeritus of zoology at the University of British Columbia, who conducted the investigation at the invitation of UC Davis Vice Chancellor for Research Prasant Mohapatra.

“The support staff, faculty and students, who dealt with the catastrophe are to be commended for their collective responses to the catastrophe. The responses were both rapid and appropriate,” Farrell wrote in the report.

Farrell recommended a series of steps to replace the disinfection system, refit water lines and develop new operating procedures for emergencies as well as making long-term investments in infrastructure and staffing at the center. Action on these steps is either complete or ongoing. The campus has committed to funding improvements at the center.

We are thankful for our campus partners, staff, faculty and students who have been instrumental in rebuilding the facility quickly and with compassion so that our aquatic conservation programs could be restored. CABA welcomed fish back into the facility in October 2022.

Media Resources

Full report available here

Media Contact

  • Andy Fell, News and Media Relations, 530-304-8888,

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