Sawfish are one of the most globally endangered groups of elasmobranchs. Of the five species described, three species are listed as critically endangered and two as endangered on the IUCN Red List of Threatened SpeciesÔ.1 There is very little known about their natural histories in the wild. Therefore, any data collected from their managed care is valuable to studying and protecting the species in the wild.
Over the course of 8 months, a proliferative mass developed on the distal aspect of the left pelvic fin of a 16-year-old, female, longcomb sawfish (Pristis zijsron). A biopsy sample of the mass was opportunistically collected during a dive utilizing a handheld biopsy forceps. The mass was diagnosed as a papilloma via histopathology.2 The papilloma continued to increase in size over the next 8 months, reaching approximately 12 cm in diameter and was raised approximately 3 cm from the surrounding skin surface. At this point surgical removal was elected.
The sawfish was restrained in a large net, moved into a medical pool and placed on a purpose-built PVC-pipe surgical table. 320 mg (1.9 mg/kg) of propofol was administered intravenously into the dorsal fin sinus and the sinus was flushed with 60 cc of shark ringers.3,4,5 The sawfish was ventilated using an aquarium pump attached to long rigid tubing placed in the mouth.4,5,6 The propofol dose provided 30 minutes of anesthesia. Supplemental sedation was provided with 1.5 gm/L buffered MS-222 solution administered into the gill arches, spiracles, and mouth using a pump sprayer.4,5
The left pelvic fin was elevated with foam pads and the surgical site was locally blocked with 200 mg of lidocaine subcutaneously. A full thickness incision was made 2 cm medial to the edge of the papilloma on the cranial aspect of the left pelvic fin with a filet knife. The incision was extended in a half circle shape maintaining 2 cm of healthy tissue margins around the papilloma. Minimal hemorrhage was encountered. Two large arteries were ligated with 0–0 PDS and a few smaller blood vessels were cauterized with a surgical laser (DiodeVet 980 nm diode laser system, 800-micron fiber at 10 watts). Cartilage adjacent to the surgical margin was undermined with Metzenbaum scissors and then removed with the filet knife leaving a 2 cm perimeter of skin available for wound closure. Closure of the surgical site was accomplished by apposing the edges and closing the subcutaneous space with six simple interrupted sutures using 0–0 PDS. The skin was closed with an interrupted vertical mattress pattern by threading 0–0 PDS suture through a 1.5-inch 18-gauge needle inserted as a guide. Recovery from anesthesia was smooth and uneventful. 4 months after partial amputation of the left pelvic fin, the surgical site was completely healed. No recurrence of the papilloma has been noted 15 months postoperatively. This single case report documents the successful handling of a longcomb sawfish using a combination of propofol and MS-222 for sedation and surgical removal of a papilloma.
The authors wish to thank veterinary technicians Bernadette Maciol, Lauren Czudak, Amanda Janson, and Jennifer Jones, Wild Reef manager Lise Watson, Wild Reef senior aquarist Heather Urbaniak, and the rest of the Wild Reef and Fishes Department staff from John G. Shedd Aquarium who assisted with this procedure. In addition, the authors wish to thank Dr. Jen Flower from Mystic Aquarium, Dr. Dana Lindemann from Sea World Orlando, Drs. Tonya Clauss, Alexa McDermott-Delaune, and Chelsea Anderson from Georgia Aquarium, and Dr. Jaime Landolfi from University of Illinois Zoological Pathology Program for contributing to the successful outcome of this case.
* Presenting author
1. Harrison LR, Dulvy NK. 2014. Sawfish: a global strategy for conservation. IUCN Species Survival Commission’s Shark Specialist Group.
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