Karl plays catcher on a nationally ranked amateur baseball team. He also keeps tropical fish and invertebrates in an aquarium. He is interested in a career as a marine biologist or ichthyologist, stating, "it's a dream of mine to travel to different coral reefs around the world."
Cobia are fish being considered for aquaculture in the United States because they represent a potentially excellent food source, with high flesh quality and impressive growth rates. But to properly vaccinate, grade, and study fish, it is necessary to sedate them. Karl sought to determine the best anesthesia for cobia.
Karl tested three compounds for their sedative effects on juvenile cobia: MS 222, clove oil, and 2-phenoxyethonol. Fish exposed to 2-phenoxyethonol took the longest to reach stage 4 and 5 anesthesia, in which the fish lose their equilibrium and reflex reactions. After sedation was stopped, fish exposed to clove oil took longest to recover. Blood samples from all groups were compared with blood from controls that weren't sedated. The samples showed that anesthesia caused low pH in the fish and increased carbon dioxide and oxygen pressures. The sedated fish also showed elevated glucose levels. Karl concluded that cobia respond poorly to anesthetics, which should be used only when necessary. MS 222 had the fewest side effects.
