Florida Red Tides, Manatee Brevetoxicosis, and Lung Models.

Area of Science:

• Marine Mammal Health
• Ecotoxicology
• Respiratory Physiology

Background:

• Mass mortality events of Florida manatees (Trichechus manatus latirostris) in 1996 were linked to brevetoxin from Florida red tide (Karenia brevis) blooms.
• Necropsy findings suggested chronic inhalation or ingestion of brevetoxin as the cause of death.
• Understanding manatee respiratory patterns is crucial for estimating toxin deposition in the lungs and assessing inhalation risk.

Purpose of the Study:

• To define the breathing pattern of Florida manatees, including respiratory volumes and flow rates.
• To provide data necessary for constructing laboratory models of manatee lungs for further toxicological studies.

Main Methods:

• Two trained, captive-born Florida manatees were fitted with a mask over their nares.
• The mask was connected to a spirometer to measure breathing volumes and flow rates in situ.
• Data were collected while manatees breathed normally through the mask.

Main Results:

• Manatees exhibited high tidal volumes.
• Inspiratory and expiratory phases were characterized by short durations.
• High respiratory flow rates were recorded, consistent with observed natural breathing behaviors.

Conclusions:

• The study successfully characterized Florida manatee breathing patterns, demonstrating high volumes and rapid, high-flow breaths.
• These findings are essential for future research on brevetoxin inhalation and risk assessment in manatees.
• This data will aid in developing more accurate models of toxin deposition in the manatee respiratory system.