2018–2019 Bottlenose Dolphin Unusual Mortality Event Southwest Florida (Closed)

The Unusual Mortality Event involving bottlenose dolphins in southwest Florida that began in July 2018 is over. Strandings occurred in Collier, Lee, Charlotte, Sarasota, Manatee, Hillsborough, and Pinellas counties.

Southeast

Scientists taking measurments of a dead dolphin in a lab during a necropsy

Taking measurements of a dead bottlenose dolphin during a necropsy. Photo credit: Mote Marine Laboratory

The Unusual Mortality Event involving bottlenose dolphins in southwest Florida that began in July 2018 is over. The event was investigated by NOAA Fisheries and partners and was defined as occurring from July 1, 2018, through June 30, 2019, along the southwest Florida coast. Strandings occurred in Collier, Lee, Charlotte, Sarasota, Manatee, Hillsborough, and Pinellas counties.

183 bottlenose dolphins were stranded during the event, including 7 live dolphins. The majority of carcasses were in moderate to advanced states of decomposition. Based on necropsy, histopathology, and diagnostic findings, the mortality event was caused by exposure to biotoxins related to a Karenia brevis algal bloom. Karenia brevis produces brevetoxins that can affect the central nervous system of fish and other vertebrates such as dolphins, manatees, birds, and sea turtles, causing these animals to become ill and die.