Study supports ovariectomy for reproductive disease in female elasmobranchs

A newly published case series in Frontiers in Veterinary Science offers fresh clinical evidence that ovariectomy can be a viable treatment for reproductive disease in aquarium-managed female elasmobranchs when medical therapy falls short. The paper, led by Daniela Yuschenkoff and colleagues, reviewed 20 female sharks and rays across nine species treated at six zoological institutions or aquariums, making it a notable addition to a still-limited evidence base in elasmobranch surgery and reproductive medicine. (frontiersin.org)

The study arrives as aquarium and zoo veterinarians continue to navigate a difficult reality: reproductive disease in managed female elasmobranchs is being recognized more often, even as the field still lacks deep species-specific guidance. Earlier literature has suggested that some pathologies may be linked to the biology of managed populations, including female-only groups and interrupted natural reproductive cycles. A 2022 review in Frontiers in Marine Science noted that ovariectomy emerged in part from attempts to manage collections in which reproductive disease may have been caused by, or worsened by, the absence of pregnancy cycles that would normally occur in the wild. (frontiersin.org)

In the new report, all animals presented with ovarian or uterine abnormalities, including ovarian enlargement from cysts or chronic follicle retention, yolk coelomitis, and excess uterine fluid. Medical management, mainly hormonal and antibiotic therapy, had failed, and the authors said the patients were unlikely to survive long term without further intervention. Across 22 procedures, clinicians used complete or partial unilateral ovariectomy, but approaches to surgery, anesthesia, and intraoperative treatment varied by species and institution. (frontiersin.org)

The outcomes were mixed, which is part of what makes the paper useful. Post-operative complications were common, especially hyporexia, wound dehiscence, and persistent bacterial coelomitis in animals already affected before surgery. The reported mortality burden was substantial: 32% of patients died directly from surgical or post-surgical complications, while another 18% died after surgery because of pre-existing disease or systemic compromise. At the same time, the authors reported that outcomes improved as teams refined anesthetic plans and intensified peri-procedural supportive care, and successful cases saw clinical signs resolve. Two Chilean round rays also required a second ovariectomy after a functional contralateral ovary developed following unilateral surgery, a reminder that incomplete suppression of reproductive function can remain an issue. (frontiersin.org)

The broader literature helps explain why this matters beyond a single case series. A 2019 study of southern stingrays found no reproductive disease in the wild or in semiwild animals studied, but identified developing or advanced reproductive disease in 65% of aquarium-housed stingrays evaluated. A 2024 report on polycystic ovarian disease in aquarium-managed cownose rays likewise described nonspecific signs, or no obvious signs at all, underscoring how easily disease may progress before intervention. Separate work on prophylactic ovariectomy in southern stingrays has also shown that aquariums have been exploring surgery not only as treatment, but as a population and health-management tool when no effective chemical contraceptive options are available. (pubmed.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, especially those in aquatic, zoo, and exotic animal practice, this paper provides a more concrete framework for discussing when surgery becomes reasonable after failed medical management. It also highlights a tension many institutions already recognize: the same managed-care setting that makes long-term monitoring and advanced imaging possible can also create reproductive patterns that differ from wild conspecifics. In practical terms, the report supports earlier recognition of ovarian and uterine disease, careful counseling around surgical risk, and strong investment in anesthesia planning, post-op monitoring, nutrition support, and infection control. It also suggests that unilateral procedures may not always be definitive, depending on species and ovarian function. (frontiersin.org)

Expert reaction specific to this paper was limited in publicly available sources at the time of writing, but the surrounding literature points in a consistent direction: aquariums are becoming important centers for generating reproductive data in elasmobranchs, because many life-history and disease questions are difficult to answer in free-ranging animals. That gives this report added weight as a multi-institutional clinical contribution, even with its retrospective design and heterogeneous case management. (frontiersin.org)

What to watch: The next step for the field will likely be more standardized multi-center protocols, particularly around anesthesia, perioperative support, imaging-based case selection, and follow-up after unilateral ovariectomy, as institutions try to lower complication rates and define which patients benefit most from surgery. (frontiersin.org)