DAVIS— A dangerous amount of chlorine entered the tanks where fish were kept at an aquatic research center at the University of California, Davis, on Aug. 15, killing about 21,000 fish.
The university said it would investigate “where our process failed” and initiate an independent external review.
“We share the grief of the faculty, staff, and students who worked to care for, study, and conserve these animals,” U.C. Davis said in a statement.
The fish were found dead on Aug. 16 in several tanks at the Center for Aquatic Biology and Aquaculture, which is home to research programs focused on sustaining California’s aquatic species and supporting sustainable aquaculture production, according to the center’s website. Dr. Laurie Brignolo, executive director of the Research and Teaching Animal Care Program at U.C. Davis, said university officials believe the source of the chlorine was a chlorination system used to decontaminate water with fish pathogens. If that was the source, university officials do not know how the chlorine ended up in the fish tanks. One explanation could be that a backup in the waterline system caused the chlorine to move in the wrong direction.
The center was built in the 1950s and had never had such “an all-encompassing loss” of fish, Dr. Brignolo said. Workers must complete daily quality assurance examinations on the pump and the water going through. The night before the loss, Dr. Brignolo confirmed that the fish had been inspected.
However, overnight, enough chlorine had entered the tanks comparable to the amount in tap water which is a dangerously high amount for fish. Fish are not supposed to be kept in water containing even small quantities of the chemical. The chlorine damaged the sensitive gills and skin of the center’s various fish species, including green and white sturgeon and Chinook salmon, which are endangered. Within 12 hours, almost all of the fish were dead.
Researchers and graduate students have been using the fish to study the effects of disease and environmental changes on specific species.
The considerable loss of fish at the center won’t completely shut down researchers’ studies, but it will significantly set them back for years.