Manatee research & Conservation

Current Conservation Status

The Order Sirenia is composed of manatees (Family Trichechidae) and dugongs (Family Dugongidae). The Trichechids are represented by three species: the West African manatee, the Amazonian manatee and the West Indian manatee, which is further divided into the Florida and Antillean subspecies. The Dugongids are represented by the dugong and the recently extinct Stellar’s Sea Cow.

According to the IUCN Red List of Threatened Species, the current population trends of the Amazonian manatee and West Indian manatee are decreasing, while the dugong and West African manatee population trends remain unknown. Each species of sirenian faces its own set of unique threats; however, overarching challenges include watercraft collisions, habitat degradation/destruction, entanglement with fishing gear, red tide events, harassment and illegal hunting.

In order to develop effective conservation efforts for manatees and dugongs, much needs to be studied and learned about these vulnerable marine mammals.

Early History of Manatees in Panama

Archaeological evidence from Bocas del Toro, Panama shows that manatees were an important source of meat for early occupants of the area during pre-Columbian and Historic Period times (Cramer,2013; Wake et al., 2013). Manatee remains found in middens (along with the remains of other animals such as bivalves, fish and turtles) reveal that manatees were among the most important marine animals consumed (Cramer, 2013). Their meat, fat, hides and bones were important resources for these early inhabitants (Wake et al., 2013) and distant groups would travel to the area to obtain them, suggesting that Bocas del Toro either had a large population or that manatees had yet to be overexploited (Cramer, 2013). Written accounts by early Caribbean explorers describe the overwhelming number of manatees, along with other marine animals, that were removed during this time period (Cramer, 2013). Unfortunately, due to the vast overexploitation of marine resources during this time period and the period of time directly following, few manatees remain in the area.

Current Manatee Populations in Panama

Only two populations of manatees remain in Panama: one in Bocas del Toro in the San-San Pond Sak Wetland Reserve and another in Lake Gatun (part of the Panama Canal Watershed). These populations currently face threats from illegal hunting, habitat degradation and low genetic diversity (Mou Sue et al., 1990). Due to the low visibility conditions of the water, the limited numbers and elusive behavior of the remaining manatees, it is extremely difficult to provide an accurate abundance estimate of the populations. Without a better understanding of the ecology of these populations, manatee numbers may decline to an unrecoverable point in Panama.  

Potential Areas of Research

Few studies have been completed on manatees of either population in Panama. As a result, TCC is focused on creating a collaborative network with other researchers/organizations in order to develop a more thorough understanding of the ecology unique to manatees in Panama to better protect them and conserve the environment they utilize.

 Areas of potential work include:

  •  Stable Isotope Analysis Studies – Stable isotope techniques have been successfully used to study the foraging ecology of other marine mammals. Using similar techniques we will be able to investigate the foraging ecology of manatees in the Bocas del Toro area to estimate what constitutes their overall diet. A stronger understanding of the foraging ecology unique to the Bocas del Toro population will allow us to better protect and preserve the environment they use.
  • Toxicology Studies – Few studies have looked at the bioaccumulation and/or the toxicological effects of agricultural runoff (pesticides, herbicides, etc.) on manatees. With the large amount of agriculture (cacao, banana farming, etc.) in the area, looking at the potential toxicological effects of this runoff on the manatee population will help in our conservation efforts. The techniques could be extended to other species in the same area as well, such as fish and invertebrates, to provide a perspective on the ecosystem effects as a whole.
  • Reproductive Endocrinology Monitoring Studies – The reproductive endocrinology of sirenians is not well understood. Studying the reproductive endocrinology of the Bocas del Toro population will allow us to estimate timing of important reproductive events in females. This will give us an understanding of the most influential times of reproduction that allow this population to continue to exist.
  • Tagging Studies – Tagging individuals will allow us to estimate the total distribution of this population and determine important areas of frequent use and areas that may coincide with seasonal usage.

 For more information on TCC's manatee research and conservation efforts, please contact info@tropicalcc.org

References

Cramer, K. L. (2013) History of human occupation and environmental change in western and central Caribbean Panama. Bulletin of Marine Science 89(0), 955-982.

The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 18 January 2015.

Mou Sue, L. L., Chen, D. H., Bonde, R. K., & O’Shea, T. J. (1990) Distribution and status of manatees (Trichechus manatus) in Panama. Marine Mammal Science 6(3), 234-241.

Muschett, G. (2008). Distribution and genetic studies of the manatee (Trichechus manatus) in the Panama Canal Watershed. (Unpublished Master’s Thesis) Pontificia Universidad Catolica de Chile.

Rivera-Chavarria, M. R., Guzman, H., & Castro, J. (2014). Detecting and locating manatees in a zero visibility environment. The Journal of the Acoustical Society of America 135, 2333.

Wake, T. A., Doughty, D. R., & Kay, M. (2013) Archaeological investigations provide late Holocene baseline ecological data for Bocas del Toro, Panama. Bulletin of Marine Science 89(4), 1015-1035.