Effectiveness of Three Compounds to Anesthetize Rainbow Trout during PIT Tag Implantation Surgery

Abstract

This study evaluated the efficacy of two potential zero‐withdrawal anesthetics, Benzoak (20% benzocaine; 50, 60, and 75 mg/L) and Aqui‐SE (50% eugenol; 50, 60, and 75 mg/L) compared with tricaine methanesulfonate (MS‐222; 55, 80, and 100 mg/L), to anesthetize Rainbow Trout Oncorhynchus mykiss for PIT tag implantation surgery. In general, higher doses resulted in faster induction time to stage 4 anesthesia (defined by the cessation of reflex activity). At 204 s, the time to stage 4 anesthesia was slowest using MS‐222 at 55 mg/L, followed by 50 mg/L of either Benzoak and Aqui‐SE, which in turn were significantly slower to induce this level of anesthesia than were Benzoak or Aqui‐SE at 60 or 75 mg/L or MS‐222 at 80 mg/L. At 100 mg/L, MS‐222 had the quickest time, 57 s, to stage 4 anesthesia. Time to recovery was longest for Rainbow Trout exposed to any concentration of Aqui‐SE and shortest for MS‐222, and recovery times from Benzoak were intermediate. Although Rainbow Trout length and weight varied significantly among the treatments, time to anesthesia and recovery were more dependent on the anesthetic and concentration used. In our opinion, doses of either Benzoak or Aqui‐SE of greater than 60 mg/L will induce rapid anesthesia and provide relatively quick recovery times for adult Rainbow Trout.Received July 27, 2012; accepted January 10, 2013

Effects of Anesthetic Disposal on the Physiological and Behavioral Responses of the Lined Seahorses, Hippocampus erectus

“…It takes 48 h for the juvenile steelhead trout, Oncorhynchus mykiss , and spiny lobster, Sagmariasus verreauxi , to recover normal feeding intake after anesthetic treatment ( Pirhonen and Schreck ; Jensen et al ). For fish released into ponds or lakes after long‐term transport, a faster recovery from the anesthetic status would directly affect their survival (Anderson et al ; Kaiser et al ; Davis et al ). In this study, feeding frequency of postanesthetized seahorses dramatically declined after the anesthetic treatment by clove oil and MS‐222 and these fish needed more time (at least 7 d) to recover from the apocleisis.…”

“…Anesthesia including MS‐222 and clove oil is considered an effective sedation agent during fish transport, and the recovery time depends on the anesthetic agents and concentrations (Cooke et al ; Pawar et al ). Moreover, considering the negative effects of anesthesia, the lowest damages for aquatic organisms should be evaluated according to the responses of each species (Kaiser et al ; Davis et al ). So far, few reports have specifically focused on the functional concentrations of anesthetic agents and the concatenate sequelae by the anesthesia in seahorses (Pawar et al ).…”