Date of Award

Fall 2015

Project Type


Program or Major


Degree Name

Master of Science

First Advisor

David L. Berlinsky

Second Advisor

Stacia A. Sower

Third Advisor

Timothy S. Breton


Anesthetics are widely used in routine aquaculture operations to immobilize animals for tagging, spawning, handling, and vaccination. A number of anesthetics are currently available for finfish, but their efficacy and optimal dosage is highly species-specific. The efficacy of the anesthetic agents (tricaine methanesulfonate (MS-222), clove oil, metomidate, and 2-phenoxyethanol (2-PE)) was studied in adult, juvenile (133.3 ± 1.5 mm, 27.5 ± 8.9 g), and larval Alewives (Alosa pseudoharengus Wilson). In an initial trial, wild-caught adults were anesthetized with doses of 87.5-112.5 mg/L MS-222, 25-40 mg/L clove oil 0.5-5.0 mg/L metomidate and 0.125-0.550 mg/L 2-PE. Optimal doses for anesthesia were similar for larvae and juveniles, and were identified as: 75-100 mg/L MS-222, 40 mg/L clove oil, 5-7 mg/L metomidate, and 500 mg/L 2-PE. All juvenile fish survived 48 hours post-exposure to each optimal dose. In a longer-term (24 hour) sedation experiment, juvenile alewives were netted and exposed to low clove oil (2.5 and 5.0 mg/L) and metomidate (0.25 and 0.50 mg/L) doses, and plasma cortisol was measured. Fish exposed to the clove oil treatments exhibited a cortisol stress response that was prolonged in the higher dose treatment. No cortisol stress response was observed in the metomidate treatments. Overall, optimal acute anesthesia doses for alewives were similar to those reported for other species, and metomidate may be useful for longer-term sedation.