Efficacy and Hematological Responses of Walleyes to Chemosedation and Electrosedation

Abstract

We conducted a series of experiments to assess Walleyes Sander vitreus that were sedated with tricaine methanesulfonate (150 mg/L), eugenol (60 mg/L), benzocaine (150 mg/L), carbon dioxide (CO2; 360 mg/L), or pulsed‐DC electrosedation (100 or 150 V; 5 or 10 s). Fish were sedated individually or in groups and were allowed to recover in order to determine induction and recovery times. Blood samples were collected from group‐sedated fish over a 6‐h postsedation period to assess physiological indicators of stress. Electrosedation yielded the fastest mean ± SE induction (0.1 ± 0.0 min), and CO2 yielded the slowest (2.1 ± 0.5 min). Recovery times varied, but most fish recovered within 1–3 min and all fish recovered within approximately 5 min postsedation. Voltage and exposure time had little effect on induction, but fish that were exposed to 150 V of pulsed DC for 10 s took approximately twice as long to recover as other electrosedated fish. Plasma cortisol levels increased substantially from 0.5 to 1.0 h postsedation regardless of the sedative used, and plasma glucose levels increased substantially throughout the 6‐h postsedation sampling period. Results show that juvenile Walleyes can be effectively sedated with any of the sedation options, but sedative exposure does induce an acute stress response.

Evaluation of Blue Catfish Blood Glucose Levels When Exposed to Various Livewell Conditions

“…The release of those two hormones then activates a secondary response which includes elevated blood glucose levels as well as increased respiration rate, increased blood flow to gills, and increased gill permeability (Barton 2002). A growing number of studies have used readily available portable blood glucose meters to quantify stress levels of fish affordably and effectively while in the field (Evans, Shoemaker, and Klesius 2003; Baker, Peake, and Kieffer 2008; Hanson et al 2008; Crosby et al 2010; Crosby et al 2012: Gause et al 2012; Trushenski, Johnson, and Bowker 2018; Ball, Goode, and Weber 2020). However, the applicability of this method has not been assessed on Blue Catfish.…”