Electrosedation of freshwater fishes for the surgical implantation of transmitters

Abstract

Although electrosedation is becoming a frequently used technique to anaesthetize fish for a variety of commercial, management, and research applications, limited information is available on the effectiveness of different settings (e.g., voltage, frequency, shocking duration) and target species. We examined recovery times and short-term survival while using a commercially available electroanaesthesia unit to prepare fishes for transmitter implantation surgeries and ran experimental tests without surgery on different electrosedation settings. Our results indicate that electrosedation is a quick and efficient form of anaesthesia, with full anaesthesia achieved, surgeries completed, and recovery in under 10 min for common carp (Cyprinus carpio L., 1758), goldfish (Carassius auratus (L. 1758)), and others. We had zero mortality over at least 24 h associated with electrosedation. We found no significant differences in recovery times related to species or mass, nor did we find any significant changes to recovery time when changing voltage applied, frequency, shocking duration, or when changing the type of pulse applied (e.g., burst pulses vs. standard pulse). Although further researches are needed to address the sublethal and long-term effects of eletrosedation, these findings are important to researchers for selecting suitable target species and optimizing recovery time and survival for a quick release after surgery, tagging, or any time fish sedation is required.