#1 THREAT: HUMAN BOAT COLLISIONS

The biggest threat to manatees involve boat collisions. Manatees swim in shallow waters at a slow pace and their main source of food is found at shallow waters. This also happens to be where there is a lot of boat activity. As a result, they are often struck by human vessels. In the first six months of 2019, 89 manatees were killed by boat collisions. While not every manatee struck by a boat dies, 97% of manatees have injuries related to boating incidents. This human-related threat is the leading cause of manatee deaths.

#2 THREAT: ALGAL BLOOMS

Manatees main source of food is seagrass. Since seagrass is being killed off by the immense amounts of nutrient pollution, many manatees are starving from lack of food sources.

Nutrient runoff from fertilizers, pesticides, and herbicides is seeping into estuaries and causing a build-up of algae. The algae and fertilizer nutrients are creating a layer between the surface of the water and seagrass. Seagrasses are found in deeper parts of the ocean, but due to the lack of sunlight being able to penetrate the nutrient layer, seagrasses have moved to more shallow waters.

Nitrogen and phosphorus are two of the most detrimental nutrients found in runoff, as they provide an environment where algae can thrive. This leads to decreased levels of oxygen and an uninhabitable territory that severely impacts the respective ecosystem. These low-oxygen environments with high amounts of algae are called algal blooms.

In May of 2021, 749 manatee fatalities were recorded by the Florida Fish and Wildlife Conservation Commission. The record high fatality rate was 804 deaths in 2018 and 2021 is on track to exceed that number. Manatees are dying of starvation and hypoxia (low levels of oxygen) created by algal blooms.

Florida has recently been hit by one of the worst red tides, a harmful algal bloom (HAB) created by the Karenia brevis microorganism, that has spread to be the size of Connecticut. This red tide killed around 200 manatees between the 2017-2018 year. 26% of the manatees killed in 2018 were caused by the Florida red tide.