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USGS · 70022710

Chemical anesthesia of Northern sea otters (Enhydra lutris): Results of past field studies

Daniel H. Monson·C. McCormick·Brenda E. Ballachey
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Abstract

Between 1987 and 1997, we chemically immobilized 597 wild sea otters ( Enhydra lutris ) in Alaska for the collection of biological samples or for surgical instrumentation. One drug-related sea otter fatality occurred during this time. Fentanyl in combination with diazepam produced consistent, smooth inductions with minimal need for supplemental anesthetics during procedures lasting 30-40 min. Antagonism with naltrexone or naloxone was rapid and complete, although we observed narcotic recycling in sea otters treated with naloxone. For surgical procedures, we recommend a fentanyl target dose of 0.33 mg/kg of body mass and diazepam at 0.11 mg/kg. For nonsurgical biological sample collection procedures, we recommend fentanyl at 0.22 mg/kg and diazepam at 0.07 mg/kg. We advise the use of the opioid antagonist naltrexone at a ratio of 2:1 to the total fentanyl administered during processing.

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Daniel H. Monson, C. McCormick, Brenda E. Ballachey. 2001. Chemical anesthesia of Northern sea otters (Enhydra lutris): Results of past field studies. https://doi.org/10.1638/1042-7260(2001)032%5B0181%3Acaonso%5D2.0.co%3B2

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