West Indian manatees have made a partial recovery from hunting but now face chronic threats from boat propeller strikes, cold stress syndrome, and loss of warm water refuges.
Manatees suffer profoundly from boat propeller strikes, which cause deep lacerations, bone damage, and sometimes death. Injured animals at facilities like Sea World Orlando have required years of rehabilitation. Even non-fatal strikes cause chronic pain and impaired mobility. Cold stress syndrome causes pneumonia, skin lesions, and death when manatees cannot access warm water refuges. Loss of warm water discharge from power plants has created a new threat as plants close. Harassment by swimmers and boaters causes stress. Red tide algal blooms linked to agricultural nutrient runoff have caused mass mortality events. The 2021 mass mortality event killed over 1,000 manatees, the worst recorded.