Abstract

During the last decade, 44 cases involving five species of sturgeon—Gulf of Mexico (Acipenser oxyrinchus de sotoi), shortnose (A. breviostrum), Atlantic (A. oxyrinchus), shovelnose (Scaphirhynchus platorynchus), and Russian (A. guldenstadi)—have been examined at the University of Florida Fisheries Diagnostic Laboratory. The greatest number of cases (34) were with Gulf of Mexico sturgeon; seven cases were with shortnose sturgeon, one case with Atlantic sturgeon, one case with shovelnose sturgeon, and one case with a Russian sturgeon. Bacterial infections composed the largest group of observed illnesses, found in 25 cases (56%). Water chemistry problems were found in five cases; external parasites (Ichthyobodo sp., Dactylogyrus sp.) in three cases; Candida in three cases; trauma in four cases, and neoplasia in one case. Two cases involved an overall health screen of Gulf of Mexico sturgeon. Etiologies in seven cases were inconclusive and regarded as unknowns.

Of the bacterial infections, Aeromonas hydrophila was predominant (13 cases) and was isolated from heart, nares, swimbladder, posterior kidney, liver, brain and external lesions. Streptococccus sp. was found in eight cases, isolated from heart, posterior kidney, liver, swimbladder, brain, and blood. Aeromonas sobria was found in four cases, isolated from the posterior kidney and swimbladder. One case of Edwardsiella tarda was isolated from the nares of Atlantic sturgeon fingerlings. Yersinia ruckeri was isolated from the brain of an adult Russian sturgeon. Most of the observed disease agents have not previously been reported for these sturgeon species.