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Publication Date

Summer 2014

Degree Type

Thesis - Campus Access Only

Degree Name

Master of Science (MS)


Moss Landing Marine Laboratories


Gregor M. Cailliet


anesthesia, electroanesthesia, Gopher Rockfish, immediate-release anesthetic, pulsed DC, zero-withdrawal anesthetic

Subject Areas

Fisheries and aquatic sciences; Animal sciences; Biology


Chemical anesthetics requiring a mandatory withdrawal period to allow for dissipation of drug residues pose severe limitations to acoustic research conducted at sea where captured fish undergo surgical implantation of transmitters and are released shortly after treatment. The efficacy and safety of three unrestricted approaches to anesthesia were evaluated in Gopher Rockfish Sebastes carnatus: carbon dioxide (CO2), sodium bicarbonate (NaHCO3), and pulsed direct current (pDC) electroanesthesia. These immediate-release methods were used to assess anesthetic induction and recovery times, plasma cortisol concentrations, and survival rates following surgery compared to those obtained from the widely used chemical anesthetic, tricaine methanesulfonate (MS-222). All anesthetics were effective at the concentrations tested. However, the times required to achieve stage IV anesthesia differed significantly, being shortest for electroanesthesia (nearly instantaneous) and longest for CO2 (3.56 ± 0.21 min [mean ± SE]). Recovery times were significantly longer for NaHCO3 (7.21 ± 1.17 min) and CO2 (7.78 ± 0.93 min) compared to pulsed DC electroanesthesia (3.76 ± 0.21 min) and MS-222 (3.65 ± 0.38 min). Plasma cortisol levels differed among treatments but tended to peak around 0.5 h post-anesthesia and decline within 2 h. Given the prolonged recovery times of NaHCO3 and CO2, electroanesthesia is the most preferable method for rapid induction, recovery, and immediate release of Gopher Rockfish following surgery at sea.