An epizootic of Florida manatees associated with a dinoflagellate bloom

Marine Mammal Science
By: , and 



Over a 10-wk period in early 1982, 39 Florida manatees (Trichechus manatus latirostris) were found dead in the lower Caloosahatchee River and nearby waters of southwestern Florida. Two were killed by boats. The remainder showed no evidence of trauma. Lesions indicative of infectious agents were not identified, and bacteriological and contaminant residue findings were unremarkable. Nonspecific lesions of congestion and hemorrhage were identified in brain tissue. Numerous reports were also received of manatee morbidity. Some distressed manatees showed no biochemical lesions in clinical analyses of blood samples and recovered quickly. Timing of manatee illnesses coincided with fish and double-crested cormorant (Phalacrocorax auritus) mortality and morbidity. A widespread bloom of the dinoflagellate red tide organism (Gymnodinium breve) also coincided with these incidents. G. breve produces potent neurotoxins (brevetoxins). Circumstantial evidence links these events, and possible routes of exposure may include ingestion of filter-feeding ascidians. Ecological conditions that magnified the extent of the epizootic included an early dispersal of manatees into the area from a nearby winter aggregation site and unusually high salinities that facilitated the inshore spread of the red tide bloom. Management responses to future episodes of red tide in manatee areas are suggested.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title An epizootic of Florida manatees associated with a dinoflagellate bloom
Series title Marine Mammal Science
DOI 10.1111/j.1748-7692.1991.tb00563.x
Volume 7
Issue 2
Year Published 1991
Language English
Publisher Wiley
Description 15 p.
First page 165
Last page 179
Online Only (Y/N) N
Additional Online Files (Y/N) N