A 13-year-old, 23.8-kg, primigravid female whitetip reef shark (Triaenodon obesus) presented with a severely prolapsed cloaca near term. The prolapse could be easily reduced and there were no pups palpable on digital examination of the pelvic canal. An ultrasound examination of the uterus revealed multiple large pups that were viable, yet showing very little movement. With the clinical presentation, the presumedly increased likelihood of recurrence, and as she was determined to be in the final stages of her first pregnancy, the decision was made to surgically extract the pups.
A children's inflatable rubber pool was utilized for the procedure. The animal was anesthetized with 100 ppm of MS-222 and placed in dorsal recumbency. Ventilation was maintained by constant pumping of water through the shark's mouth and over the gills. Dissolved oxygen was kept at 120%. Intravenous elasmobranch Ringers fluids were slowly administered through a 20-gauge needle in the caudal tail vein. Complications occurred when the shark reached a surgical plane of anesthesia, as no gross evidence of voluntary respirations could be detected. A 4.5-mHz curvilinear probe placed over the heart was used to monitor the animal's cardiovascular status.
A 25-cm paramedian incision was made over the left caudoventral coelomic wall. The musculature was bluntly dissected down to the coelomic wall, which was then incised to exteriorize the left uterine horn. Stay sutures of 3-0 nylon (3-0 Ethilon) were placed through the uterine wall to help with manipulation as well as to keep saltwater from entering the incision. Two pups were then individually extracted from this horn, and the same procedure was followed on the shark's right side. Each umbilicus was ligated, cut, and the pup immediately transferred to another pool of clean water. Remaining fetal membranes and placental attachments were gently teased from the endometrial walls and removed. One male and three female pups, approximately 62 cm in length and weighing 1.2 kg, began respiring and swimming normally upon placement into the recovery pool.
The uterine incisions were closed with 3-0 polydioxanone (3-0 PDS*II), and the coelom was copiously flushed with one liter elasmobranch Ringers prior to suturing of the coelomic lining. The coelomic wall and musculature were closed as one layer with 2-0 polydioxanone (2-0 PDS*II) suture, and the same material was used to appose the skin edges. The female was then moved to a separate tank with fresh saltwater, and ram ventilation via electric pump was continued until full recovery.
The shark was kept isolated and was given ceftazidime (20 mg/kg IM q 72 h) for 30 days. She began feeding within two days. At four and seven weeks post surgery, the shark required replacement of skin sutures as there was partial dehiscence and a small knot of suture material protruding from the caudal edge of the incision. After nine weeks, she was released back into the exhibit.
This case represents the first known published report of this type of surgical procedure done in any shark species.
The authors would like to recognize the Discovery Cove Aquarium Department, Dr. Michelle Davis, Dr. Stacy DiRocco, Ms. Alice Jones, and Dr. Charles Gregory for their assistance in this case.
* Presenting author