Abstract

The California Science Center has maintained white seabass (Atractoscion nobilis) in both the exhibit kelp tank and in holding tanks. Moving white seabass was previously done with nets and physical restraint, frequently resulting in torn nets and injuries to both fish and staff. Based on limited information on using ketamine-medetomidine sedation in fish, we decided to give this a try. Eight white seabass transfers have been performed using this technique. Drugs were delivered by rapid hand injection. With some fish, trained behaviors were used for drug delivery, and in other situations the injections were given opportunistically. In one case the injections were delivered with a modified spear gun setup. The spear gun functioned well, but we had some problems with compressed air powering the darts under water.

Fish received ketamine (10–12 mg/kg) and dexmedetomidine (0.05–0.06 mg/kg) by intramuscular injection. Fish ranged in size from 8 to 22 kg. Maximum sedation occurred in 20–30 minutes. Fish were still swimming, but much less responsive to stimuli and easily maneuvered into a stretcher for transport and procedures. Six fish were reversed with atipamezole (0.5–0.6 mg/kg IM). Two fish were sedated for capture and transport of 6–8 hours. In these two fish the sedation was not reversed. They handled the transport well and there was no additional sedation used for transfer on arrival. No adverse effects were seen, and all sedations were considered successful.