Fisheries research involving surgery is aided by, and sometimes requires, anesthesia, but health and
safety regulations limit the anesthetic methods that can be used on species considered food fish. Carbon
dioxide is one anesthetic that the United States Food and Drug Administration (FDA) tolerates when
certain guidelines are met, and it complies with Institutional Animal Care and Use Committee protocols.
But, there is very little published work that characterizes this compound’s utility on marine fishes and no
studies have compared its effectiveness across species or sizes. We used acetic acid and sodium carbonate
to create a carbon dioxide rich sea water bath to induce anesthesia and measured induction time and
recovery time for five species and several sizes of marine fishes.We found that carbon dioxide quickly and
effectively anesthetized these marine fishes to stage-4 anesthesia, a level acceptable for minor surgery.
Induction time was positively related to body size (total length or wet mass), but recovery time was
independent of size. Using red drum, we also found differences between rested and fatigued individuals.
These results provide needed documentation of the effectiveness of carbon dioxide on marine fishes and
are useful for planning field studies that involve minor surgery on marine food fish.