Abstract

A 7.5-year-old, 175-kg, female bottlenose dolphin in good general health presented with a raised, grey, limbal mass on the lateral, canthal margin of the left eye. With observed increase in size and corneal invasion with secondary edema during ophthalmic evaluation, an excisional biopsy under general anesthesia was performed. The dolphin was premedicated with oral diazepam (0.26 mg/kg) and positioned in right lateral recumbency on a foam-padded surgery table. Anesthesia was induced with propofol (5.48 mg/kg) and midazolam (0.05 mg/kg) intravascular (IV) in the caudoventral peduncle and fluke veins. The dolphin was manually intubated with an 18-mm endotracheal tube and maintenance anesthesia was achieved using sevoflurane gas in oxygen with manual and positive pressure ventilation. The left eye was prepped for surgical approach and an excisional biopsy of the mass and cryosurgery was performed. Intraoperative antibiotic, ceftazidime (20 mg/kg) and anti-inflammatory, meloxicam (0.1 mg/kg) were administered intramuscularly (IM). Anesthetic reversal was facilitated by ventilating with 100% oxygen and flumazenil (0.01 mg/kg) IV and IM. The dolphin began to spontaneously breathe upon extubation, approximately one hour after discontinuing gas anesthesia. Full recovery occurred over the next hour as the dolphin was returned to a lowered pool and resumed swimming. Postoperative analgesic, tramadol (0.5 mg/kg) BID and broad-spectrum antibiotics, cefuroxime (20 mg/kg) twice daily (BID) and Baytril (5 mg/kg) BID were prescribed. The mass was examined histologically to be a melanoma. This is the first diagnosis of melanoma and treatment in a cetacean to the authors' knowledge.

Acknowledgments

We would like to thank the Animal Training, Animal Care, and Veterinary department staff at SeaWorld San Diego and Eye Care for Animals for their dedicated support and technical assistance with this dolphin's procedure.

* Presenting author