Establishment of a 2-dimensional echocardiographic protocol and reference parameters for clinically healthy southern stingrays (Hypanus americanus)

Abstract

OBJECTIVE To establish an echocardiographic technique and 2-dimensional reference parameters for southern stingrays (Hypanus americanus). A second objective was to compare echocardiographic measurements obtained from animals of different sex, size, environment, handling technique, and position. ANIMALS 84 presumed healthy, wild, semiwild, and aquarium-housed southern stingrays. PROCEDURES Animals, anesthetized and manually restrained, were positioned in dorsal recumbency, and echocardiography was performed. A subset of this population was also imaged in ventral recumbency for comparison. RESULTS Echocardiography was feasible, and reference parameters were established for this species. While some standard measurements could not be assessed due to body habitus, all valves, chambers, and the conus were clearly visualized in the majority of animals. Statistical significance was reached for some variables when comparing animals from different environments and handling methods, but these differences were not considered clinically relevant. The data were therefore separated into 2 subsets of echocardiographic reference parameters based on disc width since some of the measurements were dependent on body size. This approach mostly separated the sexes due to strong sexual dimorphism. CLINICAL RELEVANCE Limited information is available regarding cardiac disease in elasmobranchs; most of the available information on cardiac physiology focuses on a few shark species. Two-dimensional echocardiography is a noninvasive tool utilized to evaluate cardiac structure and functionality. Southern stingrays are one of the most commonly displayed elasmobranchs in public aquaria. This article expands on the growing body of information regarding veterinary care in elasmobranchs and provides clinicians and researchers with another diagnostic modality to utilize in screening for health/disease.