Abstract

Two of nine adult, female Southern stingrays (Dasyatis americana), maintained without a male in a large mixed species aquarium, presented with a decreased appetite and a prominent bulge over their caudal dorsal surfaces. Physical examination, blood collection and ultrasound were performed on the animals. The most profound ultrasound findings were a severe accumulation of hypoechoic uterine fluid in the left coelom as well as uterine cysts in the right coelom with markedly enlarged ovaries with mixed-size hypo- and hyperechoic structures. Endoscopy and fluid analysis of the uterine fluid confirmed it to be an overabundance of uterine histotroph, normally associated with pregnancy. Serum analysis revealed estrogen concentrations were markedly higher than those of females without these clinical signs, confirming an underlying reproductive disorder. Further ultrasound evaluation of the remaining females revealed two additional affected females. Inquiries to other institutions revealed multiple additional cases initiating a prospective project to document the incidence of this disease in captive populations, to identify risk factors, and to provide a full description of the disease process. The first step in the process was to describe and document ultrasonographic findings of adult female Southern stingrays with and without this reproductive disease to establish reproductive norms and to develop diagnostic images to assist with disease treatment. Ultrasonographic images from adult, female stingrays are presented documenting varying stages of normal reproduction as well as reproductive disease.

Acknowledgements

Special thanks to the aquarium and hospital staff at the Disney Epcot's The Seas with Nemo and Friends; the veterinary department at Disney's Animal Kingdom and Daniel P. Fahy, Nova Southeastern University Oceanographic Center, Dania Beach, FL.