Following the 24-hour test exposure, we
placed 10 fish from each tank in a freshwater euthanasia bath of
200 mgL−1 MS-222 buffered to pH 7.0 with 500 mgL−1 sodium bicarbonate
(NaHCO3), and placed the other 10 fish in a saltwater euthanasia
bath with the same concentration ofMS-222.