Reproductive Neoplasms in Wild and Long-Term Captive Female Florida Manatees (Trichechus manatus latirostris)
1Department of Large Animal Clinical Sciences, Aquatic Animal Health Division, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA; 2Marine Mammal Pathobiology Laboratory, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL, USA; 3Marine Mammal Pathology Services, Olney, MD, USA; 4Tampa’s Lowry Park Zoo, Tampa, FL, USA; 5University of Illinois Zoological Pathology Program, IL, USA; 6Miami Seaquarium, Key Biscayne, FL, USA
The endangered Florida manatee (Trichechus manatus latirostris) has been the focus of numerous studies and conservation efforts due to population threats from anthropogenic and environmental pressures such as watercraft trauma, harmful algal blooms and extreme cold water temperatures. Understanding manatee reproduction is important for population management. Currently little is known about reproductive pathology in this species, including neoplasia, as no reports of uterovarian neoplasia exist in the veterinary literature. This case series presents reproductive neoplasms and pathologies in eight wild and long-term captive female Florida manatees obtained through a carcass recovery program managed by Florida Fish and Wildlife Commission’s Marine Mammal Research and animal rehabilitation programs between April 2009 and May 2014. Neoplastic categories included granulosa cell tumor, leiomyoma, uterine carcinoma and ovarian adnexal tumor. One manatee had more than one neoplasm, and another also had pyometra. Underlying causes and predisposing factors to tumor development, and their effects on reproductive success are currently unknown. Asymmetric reproductive aging, as seen in elephants and white rhinos,1-3 and a correlation between obesity and reproductive disorders in long-term non-reproductive female manatees are of interest and warrant further investigation.
The authors graciously acknowledge the biologists and veterinarians of the Marine Mammal Pathobiology Laboratory for collection of samples; Donna Szemer and Jim Valade for providing information on captive breeding policy and history; Patricia Lewis and Patrick Thompson for processing the histology samples; and photo-ID staff from the Florida Fish and Wildlife Conservation Commission, the U.S. Geological Survey Sirenia Project, and Mote Marine Laboratory for sighting histories.
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