Author(s)

G. Acevedo-Olvera, A. Delgado-Estrella, M. del R. Barreto-Castro, E. Nuñez-Lara

Abstract

Mexico has a great diversity of aquatic ecosystems. The Pom-Atasta fluvial system lagoon is part of the Flora and Fauna Natural Protected Area: Laguna de Terminos. It is a region with large areas for manatee (Trichechus mananatus manatus) distribution. This species was included in the list of Mexican species at risk, (NOM-059- and IUCN). In 2013, monitoring was conducted during three seasons; rainy, dry, and north wind. The visual recording of merely 3 animals was blamed on the increasing use of the coastal shore by human activity; usage that has fragmented many areas that were formerly occupied by manatees. Their habitat is now shared with development areas and anthropogenic activity.

There are large amounts of organic matter found in this lagoon system; a result of the numerous tributaries of the rivers. The minimum salinity (0.32‰), indicates that lagoons have a strong freshwater influence. Some sites are observed with salinity of not more than 12‰. Oxygen concentrations ranging from 4.2 to 11.3 ± 1 mg/l. The average turbidity was 60 ± 10 cm; pH 8.5 ± 0.5–9.76 ± 1; the average temperature was 28 to 30 ± 3°C; the average depth was 2.5 ± 3 m. The vegetation condition plant species such as Pontederia cordata, Pontederia rotundifolia, and Eichhornia crassipes were found with traces of manatee browsing. Many studies have recorded those plant species as manatee food. They can also be seen as an indicator of water quality. There has been an adverse change in the available habitat caused by the influence of human communities. This influence is expected to negatively affect the habitat and the many species that occupy it, especially the manatees. They are in great danger of disappearing in this area.

Keywords

antropogenyc, habitat, fluvian lagoon, manatee