Please Feed the Manatees
The West Indian manatee, Trichechus manatus Linnaeus, the endangered species that was once a great conservation success story, is once again facing threats from humans that leave the future of the species in doubt.
During the 1990s the manatee population in Florida dropped to just over 1,000. The slow moving and water surface swimming manatee were largely being killed by motorboats. Thanks to new regulations and education programs the population of manatee in Florida is above 7,000 today. However, human activity is again impacting these gentle giants. More than 1,000 of the species died in 2021, a record for a single year.
Manatees are starving due to the loss of their food source, seagrass. The cause is polluted water. Stormwater runoff and effluent from wastewater treatment plants that contain excess nutrients is causing algal blooms in the estuaries that manatee spend the cooler weather months in search of warmer water. These algal blooms leave the water low in dissolved oxygen and can kill aquatic plants such as seagrass. One significant source of fertilizer is the large sugar farms in the region.
The U.S. Fish and Wildlife Service has begun a pilot program to begin feeding manatee in the Indian River Lagoon area near Cape Canaveral. The plan is for this to be a temporary effort until seagrass beds are restored. The state of Florida also announced $481 million in water quality management grants, $53 million of which will focus on wastewater treatment in the Indian River Lagoon area.
Some scientists are skeptical of the experimental feeding program. Feeding manatees could lead to changes in the animal’s behavior which could have unknown consequences. There could also be high concentrations of manatees near the feeding sites putting the animals at risk of being struck by motorboats. Finally, any uneaten food will decay, releasing nitrogen into the water. This nitrogen could be taken in by algae and accelerate its growth, leading to the loss of additional seagrass.
The success of this program could be measured by the length of time it is needed. If the underlying causes of manatee starvation are not addressed, stormwater runoff and untreated sewage, such a highly human dependent solution like the feeding program may not be sustainable. Restoring seagrass beds will also be only a stop gap solution if the algal blooms are not reduced in a significant way. Addressing water quality is the only way to permanently protect this peaceful animal.
Originally published at https://danielcmacken.com on January 17, 2022.
