Distribution and Conservation of the West Indian Manatee (Trichechus manatus Manatus) in the Catazajá Wetlands of Northeast Chiapas, México

Abstract

Tropical coastal wetlands have a rich biodiversity, a restricted geographic distribution and are a prime habitat for manatees in the regions where they occur in the Neotropics. Human pressures affect the persistence of tropical wetland ecosystems and hence of manatees. In the continental Neotropics, the West Indian manatee ( Trichechus manatus) is represented in Mexico by the subspecies T. m. manatus. Lack of information regarding the current distribution of manatees in Mexico hampers conservation approaches of this marine mammal. In this paper we present information on a survey of a population of manatees found in the Catazajá wetlands (ca 60,000ha) in northeast Chiapas, Mexico. We additionally report on manatee conservation efforts spanning seven years aimed at involving the participation of local rural communities. Systematic surveys for the presence of manatees were conducted between Feb-Nov, 2007 by sightings along sampling transects in waterways, recording of manatee presence as evidenced by recently browsed aquatic vegetation, presence of stranded individuals and presence of deceased manatees. Additionally, some records of manatee presence underwater were obtained by using a side-scan sonar system. Lastly, interviews with 120 individuals from 10 local communities also yielded information on manatee presence in the wetland system. A map of the study area divided into a grid of 50 ha cells was used to plot and quantify the records of manatee presence obtained with the above procedures. Results indicated presence of manatees in 11% (ca 4,850 ha) of the 50 ha cells into which the study area was divided. Records indicate presence of manatees throughout the wetland, but with concentration in particular sectors. Involvement of local communities in manatee conservation has resulted in designating the Catazajá wetlands as a natural protected area.