The Florida manatee has been listed as an endangered species since 1967. No one knows the exact manatee population, now or at any point in the past. In order to get an estimate, aerial surveys are done every year over popular warm water areas frequented my manatees. The highest count to date was in 2010 in which 5,077 Florida manatees were counted, more than double what was counted a decade before[8]. Manatee populations have increased since the time of their addition to the endangered species list, but they are far from being safe. A combination of high mortality rates, low reproductive rates, and a loss of habitat have very strong negative impacts on the Florida manatee population.
Watercraft collisions
Collisions with watercrafts cause approximately 30% of all manatee deaths[12]. Manatees can be severely injured or die from blunt force trauma after colliding with fast moving boats or from lacerations caused by boat propellers. Manatees are dark colored and thus hard to see from above the surface of the water. They are also slow moving and cannot escape an oncoming watercraft. |
Net Entanglement
Manatees can become tangled in discarded nets, fishing lines, and crab traps[10]. This causes lacerations and cuts off circulation to the entangled limb. A manatee can die from the wound itself, through blood loss or infection, or can die of indirect causes, such as drowning, if it is impeded in its attempt to surface for a breath. |
Dredging
Dredging is the excavation of seafloors and river bottoms for the purpose of boat passage or construction work. Sediment is dug up from the bottom and disposed of elsewhere[9]. This practice destroys the vegetation growing from the seafloor that manatees depend on as a food source. Dredging can also physically injure manatees in the same way that fast moving boats can, through collision with the equipment. |
Floodgates
Floodgates are used in rivers and other bodies of water to control water level and water flow. They use a system of moveable gates that can trap and drown manatees, crush them, or cut them with moving parts[10]. |
Habitat Destruction
Florida's population increases by about 1,000 people each day[10]. This population growth leads to expansion of urban boundaries. New bridges and dams are built across waterways, more industrial centers are built along the coast to receive the increased imports needed to fill the demands of the larger population, and pollution worsens. Water is also siphoned from natural springs for human use, which depletes the bodies of water used by manatees[11]. |