Traumatic Injuries in Manatees (Trichechus manatus)
IAAAM 1991
Michael T. Walsh1, DVM; Gregory D. Bossart2, DVM; Terry W. Campbell1, DVM, PhD
1Sea World of Florida Inc., Orlando, FL; 2Miami Seaquarium, Miami, FL

The endangered West Indian manatee, (Trichechus manatus) a herbivorous marine mammal found in the waters of the Southeast United States, is subject to many mortality factors. Those factors affecting the manatee are generally grouped into seven categories. These include watercraft trauma, flood gate and canal lock trauma, other human related injuries (entrapment, entanglement) perinatal death, cold stress' other natural illnesses, and undetermined causes of death.

Of 87 individual manatees rescued at Sea World of Florida over a 14 year period, 41 individuals presented with traumatic injuries. Line entanglement accounted for 17 individuals, propeller wounds 16 individuals, and 8 manatees presented for blunt trauma. During 4 years at Miami Seaquarium there were 16 rescues. Of these 11 were blunt trauma and 2 had severe propeller wounds. The yearly percentage of animals killed by boat related trauma has steadily increased from 10 in 1976 to 50 individuals in 1989. Traumatic injuries incurred from watercraft (boats, ships, airboats, barges) have resulted in hard tissue trauma (skull and skeletal fractures) and soft tissue trauma (propeller lacerations, massive contusions, etc.). Two major complicating factors affecting the survival rate for trauma victims are the severity of the wounds incurred and the delay between initial injury and the time of presentation.

Treatment techniques commonly used in human and small animal chest trauma are limited by the need to maintain the animals in water whenever possible. Suturing of propeller lacerations is usually non-productive as a result of laceration age and secondary subcutaneous fatty degeneration resulting in dehiscence. Chest tubes have been utilized for pneumothorax, but this technique has two major weaknesses. Since the manatee is a breath holder, most lung perforations do not heal if the pressure is released from the bruised thorax. The valve allows a continued flow from the damaged lung held under positive pressure to the hemothorax then through the valve. The valve tubing is usually rejected by the body in 2-3 weeks, long before the lung has healed. For many instances of severe trauma the most beneficial approach is prevention by increasing protective measures for the animals in the wild.

Speaker Information
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Michael T. Walsh, DVM
SeaWorld of Florida
Orlando, FL, USA