Abstract

Reproductive disease in southern stingrays (Dasyatis americana) has been documented at multiple aquariums. Ultrasonography has been used to establish criteria for normal and abnormal stingray ovaries,¹ but criteria are lacking for assessment of the uterus. Presented here are categories for defining uterine disease. Physical exam, blood collection and ultrasound were conducted quarterly on captive (n=43) and annually on semi-free ranging (n=30) stingrays. Ultrasonographic video data were reviewed and specific criteria established on a scale of 1–5 similar to previously defined ovarian health scores of ‘normal’ and ‘abnormal.’ The criteria were established as follows: 1=no fluid evident in the uterus or pregnant (visible embryo) and a normal sized ovary; 2=a minor amount of uterine fluid and a normal sized ovary; 3=minor or moderate amounts of uterine fluid with an abnormal ovary; 4=moderate amounts of uterine fluid and the organ breaches midline and an abnormal ovary; 5=the uterus is severely filled with fluid, breaches the midline, and cystic structures may be present (apart from the functional left uterine tissue), as well as an abnormal ovary. Preliminary data showed that the mean uterine health score for captive stingrays was 3, and for semi-free ranging rays was 1 (Mann-Whitney rank test; p<0.001). Continued work will investigate endocrine and husbandry parameters to determine potential causes of this condition. Development of clearly defined criteria will aid in diagnosis and treatment of southern stingray reproductive disease.

Literature Cited

1.  Mylniczenko N, Penfold L. Ultrasound findings in southern stingrays (Dasyatis americana) with and without reproductive disease. Proceedings of the IAAAM conference. Atlanta, Georgia May 13th–16th 2012.