newer plants with more efficient cooling systems may disrupt the pattern of warm water refuges, and an increased demand on artesian springs, the animals' natural source of warm water, for human use decreases the number of warm water refuges. Congregating in the warm waters of industrial areas of Florida can expose manatees to pollutants and toxins at a time of year when their immune systems are already compromised. Sirenians can be caught as bycatch from fisheries, and they can be seen as pests that interfere with local fishermen and damage their nets. African manatees have also been known to venture into rice paddies and destroy the crops during the rainy season, and these confrontations with locals may lead to intentional killing of the manatees. Red tide, a harmful algae bloom of Karenia brevis that releases toxins into the water, kills many marine species. In 1982, many manatees were sickened by consuming brevetoxins that had accumulated in filter-feeding organisms attached to seagrass blades. Manatees can also inhale these brevotoxins from the surface of the water as they come up for air, leading to respiratory symptoms and even drowning. Manatee die-offs from exposure to red tide toxins were recorded by the Florida Fish and Wildlife Conservation Commission in southwest Florida in 2002, 2003, 2005, 2007, and 2013. A 2018 red tide bloom spread from Pasco County to Collier County off the west coast of Florida. As of January 2018 there were a total of 472 manatee deaths caused by this red tide, along with watercraft, cold stress, and other factors. Manatees have been negatively impacted by plastics and other debris that makes its way into the ocean and other waterways. Plastic and debris can result in manatee entanglement, ingestion, amputation or even death. When a manatee ingests plastic, it is often not known until after death, when a necropsy is conducted and debris is found in the manatee's GI tract. Of the 40 Antillean manatees that were rescued, rehabilitated, and released by the Clearwater Marine Aquarium Manatee Reintroduction Program along the Central and South American coast, four were found to have plastic in their GI tract. Treatment was completed and the manatees were released. Later, three of the four were found dead, two as a direct result of plastic ingestion and the third with plastic pieces in its GI tract. Items found in the deceased manatees' GI tracts included condoms, plastic bags,