|Regional Management Plan for the West Indian Manatee, Trichechus manatus|
|CEP Technical Report No. 35 1995||All CEP Technical Reports|
French Guiana (France)
Puerto Rico (USA)
Trinidad & Tobago
Status and distribution
In a country with one of the most potential manatee habitats, and where the species used to be widely distributed, numbers have been reduced (Husar 1977, Campbell and Gicca 1978) due to the growing human population and associated activities (Colmenero 1991).
Manatees occur along the southeastern coast from Nautla, Veracruz, to southern Quintana Roo; however only in the wetland systems in the state of Tabasco and the bays and coastal springs along the eastern coast of the state of Quintana Roo they are reasonably abundant (Colmenero 1984, Colmenero 1991, Colmenero and Hoz 1986, Colmenero and Zárate 1990, Lefebvre et al. 1989, Morales and Olivera 1992). Manatees are present in Quintana Roo throughout the year with an increasing gradient from north to south and greatest concentration (89-93% of state population) in Bahia de Chetumal, Laguna Guerrero and Rio Hondo (Colmenero et al. 1988, Morales and Olivera 1992). Preliminary data on spatial movements of manatees in Bahia de Chetumal (Colmenero and Zárate 1990, Zárate 1993) and knowledge of manatee movements in Florida (Rathbun et al. 1983b) support the idea that the population crosses the political border to neighboring Belize. Tabasco harbors an important population, in the area of rivers Grijalva and Usumacinta and tributaries (e.g., San Pedro, San Pablo, San Antonio, Chilapa, and González rivers) plus adjacent lagoons (Colmenero and Hoz 1986, Colmenero et al. 1990). Contrary to Tabasco, Chiapas' population is very reduced, restricted to Laguna de Catajazá and interior lagoons close to Emiliano Zapata (Colmenero and Hoz 1986, Colmenero et al. 1990). In Campeche manatees occur in several freshwater systems connected to Laguna de Términos (e.g., río Palizada-laguna del Este towards Boca Chica; río del Este-lagunas de Atasta, Pom; río Chumpán-Balchacah; and río Candelaria-Panlau) but records for the coastal area are scarce (Campbell and Gicca 1978, Colmenero and Hoz 1986). There is a reduced manatee population in the lagoons adjacent to rio de Soto (La Marina) and rio Pánuco (Tamaulipas) and Chairel lagoon (Lazcano-Barrero and Packard 1989, Colmenero et al. 1990, Colmenero 1991). In Veracruz the population is also sparse and occurs in lagoons interconnected with rio Nautla and tributaries of rio Papaloapan (Colmenero and Hoz 1986, Colmenero et al. 1990, Colmenero 1991). Manatees are scarce in northern Peninsula de Yucatan and northern Quintana Roo where animals found are mostly migrating (Gallo 1983, Colmenero and Zárate 1990, Colmenero 1991). Large bays of central Quintana Roo contain mainly isolated individuals or small groups (Colmenero et al. 1988).
At the national level, the sole information on population size is Heinsohn's (1976) overestimated 5,000 manatees. However, it is now believed that the total manatee population in Mexico ranges between 400 to 800 animals. The size of the manatee population in Quintana Roo is estimated at 110 individuals (Colmenero et al. 1988). Estimates for Bahia de Chetumal vary between a minimum of 60 (Zárate 1993) and an average of 83.3 (range of 71-95) (Morales and Olivera 1991). Bahia de Chetumal has been proposed as one of the most important mating and calving areas of western Caribbean (Morales and Olivera 1992) due to the percentage of calves varying between 5.0 and 12.4 during surveys (Morales and Olivera 1992, Zarate 1993). Arriaga and Contreras (1993, cited in Morales and Olivera 1993 unpubl. report) identified 9 manatee distribution areas in Tabasco, 4 of them containing more than 10 animals, according to information from local fishermen.
Major threats and conservation problems
Accelerated development along the coasts of Golfo de Mexico and freshwater systems of Campeche, Tabasco and Veracruz are cause of concern for the future of wetlands. Habitat is being lost along the coastal zone, new areas are being developed for tourism, improvement of urban zones and fishing activities (Morales 1993 in litt.) and both Mexico and Belize have many plans for urban development in the area of Chetumal which will undoubtedly affect the manatee population (Morales and Olivera 1992). The construction of some roads have altered the freshwater flow into Bahía de Chetumal, río Hondo and Laguna Guerrero, important areas for manatee cow-calf pairs. Another road is projected to pass over a water body that supplies freshwater to an area important to manatees in the southeast coast of the Chetumal Bay (Morales and Olivera 1993 unpubl. report). In the past 2 decades Quintana Roo has suffered fast changes in its coastal zone (Salazar-Vallejo 1992 cited in Morales and Olivera 1993 unpubl. report). A large portion of the area between Cancún and Chetumal is scheduled for massive tourism-oriented development causing a great deal of immediate concern about how future development will affect natural resources, particularly wetlands. Population growth is constant in key points such as rio Hondo, bahia de Chetumal and bays in Reserva de la Biosfera de Sian Ka'an (Morales, pers. com.). Important inlets for manatees in the corridor Cancún-Tulum have been altered, such as caleta de Xel-ha (Gallo 1983) and Xcaret, presently part of a tourist center (Morales and Olivera 1993 unpubl. report). Colmenero and Hoz (1986) suggested that manatees disappeared from the Papaloapan river and Alvarado lagoon (Veracruz) as a result of the construction of the Miguel Alemán dam, in the basin of the Papaloapan.
There have been several records of boat collisions, and deaths due to incidental entanglements in fishing nets. Gill nets set across the Usumacinta, Chacamax, and Palizada rivers for long periods of time hinder manatee movements and affect their feeding and reproductive activities (Colmenero and Hoz 1986, Morales and Olivera 1993 unpubl. report). Collisions with boats may be occurring with motorized army boats travelling from the mouth of Rio Hondo to Unión; also due to competitions of fast boats from the mouth of Rio Hondo to the mouth of canal to Laguna Bacalar, areas used by manatees (Colmenero et al. 1988).
Extensive use of pesticides in chili pepper and sugar cane plantations close to rio Hondo and other water bodies both in Mexico and Belize are a potential threat to manatees (Morales 1993 unpbl. report, Morales and Olivera 1993 unpubl. report). Many petroleum industries in Tabasco may cause water pollution (Colmenero 1991). Manatees are said to have disappeared from Coatzacoalcos and Papaloapan rivers due to pollution and boat traffic (Colmenero 1991). The city of Chetumal does not have an adequate sewage system so all household waste water is discharged into the Bahia de Chetumal (Morales and Olivera 1993 unpubl. report).
Hunting has been the greatest threat to manatee survival in Mexico until recently. However, significant numbers are not killed anymore at the mouth of Rio Hondo and Bahia de Chetumal. In the last four years, six manatees have been reported killed in the Chetumal and Rio Hondo area (Morales et.al. l993, unp. report). Subsistence and some commercial hunting persists in areas of Veracruz (Nautla, Minatitlán and Cosamaloapan) and Campeche (Colmenero et al. 1990). In Quintana Roo and other southeastern states manatee ribs are still used in the handcraft industry. Figurines and bone jewelry sell for up to US$500.00 in places like Chetumal, Cozumel, Playa del Carmen and Mérida (Morales and Olivera 1993 unpubl. report).
Socio-economic significance of the species to local communities
Mayans used the manatee, which had great meaning in daily life of these peoples (Landa 1941, Bradley 1983, McKillop 1985). The main use given to manatee has been as a source of meat for subsistence. However the meat and bones are also said to have medicinal properties and the fat is used for cooking (Colmenero et al. 1988). In several localities in Mexico manatees have until recently been considered "white meat fish" of high traditional value and which should be respected outside of Easter week. Some grant them special importance for "deepening" rivers and maintaining them clear of plants that interfere with boat traffic (Colmenero and Hoz 1985).
National legislation and conservation measures
Manatees were first protected in Mexico in 1921 and 1925, when hunting became illegal under the Ley de Pesca. In October 1981 Departamento de Pesca prohibited the commercialization of any manatee product. Manatees in Mexico are classified as "subject to special protection" by Secretaría de Desarrollo Social. The new fisheries law of Secretaría de Pesca ratifies the prohibition of manatee hunting and stipulates fines between 2001 and 20,000 minimum wages for offenders and the Calendario Cinegético (hunting calendar) maintains its total protected status. Mexico has signed both the CITES Convention and the SPAW Protocol but has not ratified SPAW. (Morales 1993 unp. report).
A proposal is being presented to the government of Mexico to declare Bahia de Chetumal as a refuge for manatees (Morales 1993 in litt.). CIQRO's initiative has received support from 12 other institutions from the areas of research, law enforcement, education, communication, tourism, fisheries, and government (Morales and Olivera 1993 unpubl. report). Tabasco has an important population of manatees within the Biosphere Reserve of Pantanos de Centla; a few manatees also receive protection in Reserve Sian Ka'an.
Colmenero (1991) elaborated a recovery plan for the Antillean manatee in Mexico and identified priority actions to be taken for the management of manatees in the country. Manatee conservation is among the activities supported by the Sociedad Mexicana para el Estudio de Mamiferos Marinos (SOMEMMA, A.C.) (Morales and Olivera 1993 unpubl. report). In a workshop conducted by CIQRO in September 1992 representatives of Belize, Mexico and the United States analyzed the regional situation and made recommendations for research and conservation priorities for Quintana Roo and Belize (Morales et al. 1992). A joint proposal for a pilot radio-tracking programme in Belize and Mexico has been submitted to funding agencies.
To date educational programmes are only being carried out at a local level: by CIQRO in southern Quintana Roo and Universidad Veracruzana in Xalapa for the area of Coatzacoalcos and Papaloapan (Veracruz) (Colmenero 1991). During September and October 1993 CIQRO was to take to 70 elementary and high schools in the vicinities of Chetumal Bay, an environmental programme on the biology of the manatee and the importance of its preservation; the environmental message is also carried to the population via television, radio and newspapers (Morales and Olivera 1993 unpubl. report). Universidad Juaréz Autónoma de Tabasco recently completed the construction of the Centro de Investigaciones para la Conservación de Espécies Amenazadas, which will include captive studies and rehabilitation of manatees (Morales and Olivera 1993).
Belize | Colombia | Costa Rica | Cuba | Dominican Republic | French Guiana (France) | Guatemala | Guyana | Haiti | Honduras | Jamaica | Mexico | Nicaragua | Panama | Puerto Rico (USA) | Suriname | Trinidad & Tobago | United States | Venezuela
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Preface and Objectives | Summary | I. Introduction | II. National Status | III. Short and Long-term... | IV. References | Appendix I | Appendix II | Appendix III | Table 1 | Manatee Map