Sedation of red porgy (Pagrus pagrus) and black sea bass (Centropristis striata) using ketamine (K), dexmedetomidine (D) and midazolam (M) delivered via intramuscular injection

Abstract

Handling and restraint of large teleost fish in public aquaria presents significant logistical and safety challenges and research into effective injectable anesthetic protocols has been limited. A combination protocol of ketamine (K), dexmedetomidine (D) and midazolam (M) injected intramuscularly was evaluated at several dose combinations in red porgy (Pagrus pagrus) and black sea bass (Centropristis striata). The response of red porgy was extremely variable, and even at the lowest dose tested (1 mg/kg K/0.025 mg/kg D/0.2 mg/kg M), multiple fish exhibited a severe, often fatal lactic acidosis. The protocol was effective in black sea bass, and the fish were consistently sedated and easily handled when anesthetized with 2 mg/kg K/0.05 mg/kg D/0.2 mg/kg M or with 4 mg/kg K/0.1 mg/kg D/0.2 mg/kg M. All black sea bass recovered well following reversal of the dexmedetomidine with atipamezole and no long-term negative effects were seen. This protocol appears to be a safe and effective approach to sedating demersal teleosts to facilitate handling and movement.