Induction, Recovery, and Hematological Responses of Largemouth Bass to Chemo- and Electrosedation

Abstract Sedating fish before handling minimizes the risk of injury to both fish and handler and may also minimize the fish's stress response. We conducted two experiments to quantitatively compare induction and recovery times of largemouth bass Micropterus salmoides sedated with tricaine methanesulfonate (MS-222), eugenol, benzocaine, carbon dioxide (CO2), or electrosedation (pulsed DC).We also assessed the fish's hematological profile following sedation with MS-222, eugenol, and electrosedation. Induction times varied significantly among the sedatives evaluated; electrosedation yielded the fastest inductions (0.2 ± 0.1 min; mean ± SE) and CO2 yielded the slowest (3.6 ± 0.1 min). Times to recovery of equilibrium and responsiveness to tactile and visual–auditory stimuli also varied, ranging from 1.8 ± 0.3 to 3.7 ± 0.3 min and from 2.3 ± 0.3 to 4.0 ± 0.3 min, respectively, depending on the sedative used. Plasma cortisol concentrations were elevated at 0.5 h postsedation among fish sedated with eugenol and ...