Mesoamerican Barrier Reef IMMA
Size in Square Kilometres
16 425 km2
Qualifying Species and Criteria
Greater Caribbean Manatee – Trichechus manatus manatus
Criterion A; Criterion B (2); Criterion C (1, 2)
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Summary
The Mesoamerican Barrier Reef IMMA encompasses critical habitats for the Endangered Antillean/Greater Caribbean manatee (Trichechus manatus manatus) along the Caribbean coasts of Mexico, Belize, and Guatemala, including coastal lagoons, riverine systems, and the Mesoamerican Barrier Reef itself. This area supports the largest and most significant populations of the Antillean manatee throughout the species’ range. Approximately 1,500 Antillean manatees (25% of the subspecies) inhabit this region year-round, making it a stronghold for the species. They are known to aggregate in groups ranging from dozens to hundreds throughout the IMMA, especially in areas abundant with seagrasses and freshwater sources. These aggregations occur in key locations such as the Sian Ka’an Biosphere Reserve (Mexico); the Drowned Cayes, Southern Lagoon, Corozal Bay, Placencia Lagoon and Turneffe Atoll (Belize); and Bahía de Amatique (Guatemala). The manatees rely on this IMMA for feeding on various seagrass species—including Thalassia testudinum, Syringodium filiforme, and Halodule spp.—as well as freshwater plants and algae. The region is also crucial for reproduction, with long-term studies documenting the presence of mothers and calves of all ages throughout the area.
Description of Qualifying Criteria
Criterion A: Species or Population Vulnerability
The West Indian manatee (Trichechus manatus) is red-listed globally as Vulnerable (Deutsch et al., 2008), while the Antillean, or Greater Caribbean subspecies (Trichechus manatus manatus) which occurs in this IMMA is listed as Endangered (Morales et al. 2024).
Criterion B: Distribution and Abundance
Sub-criterion B2: Aggregations
The Mesoamerican Barrier Reef IMMA hosts the highest numbers of Antillean (Greater Caribbean) manatees found throughout the species’ entire range (Self-Sullivan & Mignucci, 2012). The total estimated manatee population across the Mexican Caribbean, Belize, and Guatemala is approximately 1,500 individuals, representing up to 25% of the entire subspecies (Quintana-Rizzo and Reynolds, 2010; Castelblanco-Martínez et al., 2012; SEMARNAT 2020). Manatees are distributed in the coastal waters of the IMMA, including the inshore lagoons and riverine systems, and, somewhat unusually for the species, marine habitats from Mexico to Guatemala (Morales-Vela et al., 2000; Auil, 2004; Galves et al., 2023a; LaCommare et al., 2008; LaCommare et al., 2012; Castelblanco-Martínez et al., 2012). In Belize, manatees inhabit areas as far offshore as the Turneffe Atoll in Belize (Edwards et al., 2014), which hosts a population that regularly migrates to and from the mainland coast across deep water east of the barrier reef (Castelblanco et al., 2013b). Manatees are known to aggregate in dozens to hundreds year-round in core areas throughout the IMMA including Southern Lagoon, Placencia Lagoon, and Chetumal Bay with evidence from multiple years of transnational aerial surveys covering the IMMA (Unpublished aerial surveys; Castelblanco-Martínez et al 2013; Morales-Vela and Bahena-Basave 2022; Auil, 2004; Galves et al., 2023a; Galves et al., 2023b). Manatees throughout the IMMA are dependent on seagrasses and freshwater from inland water bodies, rivers, and underwater sinkholes (Morales-Vela et al., 2000; Allen et. al., 2008; Castelblanco-Martinez et al., 2013, SACD Annual Report, 2019; Gagnon, 2023). Manatees prefer areas with freshwater availability, and the IMMA includes major freshwater sources used by manatees including sinkholes (Gagnon 2023) and the middle and low reaches of rivers such as Hondo River (Castelblanco-Martínez et al. 2013, Corona-Figueroa et al 2021, Callejas-Jiménez et al. 2021), Belize River (Castelblanco-Martínez et al. 2013, Galves et al. 2023a), and others.
Criterion C: Key Life Cycle Activities
Sub-criterion C1: Reproductive Areas
Long-term studies support the presence of reproductive populations of Greater Caribbean manatees throughout the IMMA including manatee mothers and calves of all ages found throughout the region (Quintana-Rizzo, 1993; Self-Sullivan et al., 2003; Galves et al., 2023; Ramos et al., 2024; Quintana-Rizzo et al. 2023; Castelblanco-Martínez et al 2018; Morales-Vela and Bahena-Basave 2022). Reproduction appears to occur year-round given the occurrence of numerous orphaned calves of different ages including newborns, typically found stranded or in inland canals along the coast of Belize and Mexico (Galves et al., 2023a; Castelblanco-Martínez, Unpublished data). Additionally, Self-Sullivan et al. (2008) reported increased movements of male manatees across reef habitats in Belize suggesting the possibility of peak reproductive periods in the region.
Sub-criterion C2: Feeding Areas
Antillean manatees inhabiting the IMMA are dependent on various species of seagrasses for their survival, including Thalassia testudinum, Syringodium filiforme, and Halodule spp; and a variety of algae and plants from estuarine and freshwater environments (Castelblanco-Martínez et al. 2009; Flores-Cascante et al 2013; Allen et al., 2018; Ramos et al 2024; Garcés-Cuartas 2020). Different areas including Sian Ka’an Biosphere Reserve (Mexico, Castelblanco-Martinez, 2018), Southern Lagoon (Belize, for its abundant Halodule spp: Unpublished aerial surveys; Galves et al., 2023a), Placencia Lagoon (Belize, Unpublished aerial surveys; Ramos et al., 2024), Turneffe Atoll (Belize, Edwards et al., 2014), and Bahia de Amatique (Guatemala; Quintana-Rizzo, 1993; Arrivillaga and Baltz, 1999) support large expanses of seagrass beds on which manatees feed (Quintana-Rizzo et al., 2023; Ramos et al., 2024).
Supporting Information
Allen, A. C., Beck, C. A., Bonde, R. K., Powell, J. A., & Gomez, N. A. (2018). Diet of the Antillean manatee (Trichechus manatus manatus) in Belize, Central America. Journal of the Marine Biological Association of the United Kingdom, 98(7), 1831-1840.
Arrivillaga, A., & Baltz, D. M. (1999). Comparison of fishes and macroinvertebrates on seagrass and bare-sand sites on Guatemala’s Atlantic coast. Bulletin of Marine Science, (65): 301–319.
Auil, N. E. (2004). Abundance and distribution trends of the West Indian manatee in the coastal zone of Belize: implications for conservation (Doctoral dissertation, Texas A&M University).
Callejas‐Jiménez, M. E., Alcérreca‐Huerta, J. C., Morales‐Vela, B., & Carrillo, L. (2021). Spatial and seasonal variations in surface water temperature and salinity in the Mexico‐Belize riverine estuary: Possible comfort conditions for manatees?. Marine Mammal Science, 37(4), 1454-1474.
Castelblanco-Martínez (2018). Conocimiento y conservación de los mamíferos marinos en el Complejo Sian Ka’an. Reporte Final. Programa de Recuperación y Repoblamiento de Especies en Riesgo, Comisión Nacional de Áreas Naturales Protegidas. 40 pp. https://panorama.solutions/sites/default/files/conocimiento_y_conservacion_de_los_mamiferos_marinos_en_el_complejo_sian_kaan.pdf
Castelblanco Martínez, D.N., Morales Vela, B., Hernández Arana, H.A., & Padilla Saldivar, J. (2009) Diet of the manatees (Trichechus manatus manatus) in Chetumal Bay, Mexico. In Lat. Am. J. Aquat. Mamm., 7(1-2), 39-46.
Castelblanco-Martínez, D. N., Slone, D. H., Landeo-Yauri, S. S., Ramos, E. A., Álvarez-Alemán, A., Attademo, F. L., … & Mignucci-Giannoni, A. A. (2021). Analysis of body condition indices reveals different ecotypes of the Antillean manatee. Scientific Reports, 11(1), 19451.
Castelblanco-Martínez, D. N., Nourisson, C., Quintana-Rizzo, E., Padilla-Saldivar, J., & Schmitter-Soto, J. J. (2012). Potential effects of human pressure and habitat fragmentation on population viability of the Antillean manatee Trichechus manatus manatus: a predictive model. Endangered Species Research, 18(2), 129-145.
Castelblanco-Martínez, D. N., Barba, E., Schmitter-Soto, J. J., Hernández-Arana, H. A., & Morales-Vela, B. (2012). The trophic role of the endangered Caribbean manatee Trichechus manatus in an estuary with low abundance of seagrass. Estuaries and Coasts, 35, 60-77.
Castelblanco‐Martínez, D. N., Padilla‐Saldívar, J., Hernández‐Arana, H. A., Slone, D. H., Reid, J. P., & Morales‐Vela, B. (2013). Movement patterns of Antillean manatees in Chetumal Bay (Mexico) and coastal Belize: A challenge for regional conservation. Marine Mammal Science, 29(2), E166-E182.
Castelblanco-Martínez, D. N., Powell, J., Galves, J., & Auil Gomez, N. (2013b). Preliminary information from first tagged manatees in Turneffe Atoll (Belize) reveal regular travel patterns to the mainland. Sirenews, 60, 12-13.
Corona-Figueroa, M. F., Ríos, N., Castelblanco-Martínez, D. N., Vilchez-Mendoza, S., Delgado-Rodríguez, D., & Niño-Torres, C. A. (2021). Searching for manatees in the dark waters of a transboundary river between Mexico and Belize: a predictive distribution model. Aquatic Ecology, 55(1), 59-74.
Deutsch, C.J., Self-Sullivan, C. & Mignucci-Giannoni, A. 2008. Trichechus manatus. The IUCN Red List of Threatened Species 2008: e.T22103A9356917. https://dx.doi.org/10.2305/IUCN.UK.2024-2.RLTS.T22103A43792740.en
Edwards, H. H., Stone, S. B., Hines, E. M., Gomez, N. A., & Winning, B. E. (2014). Documenting manatee (Trichechus manatus manatus) presence at Turneffe Atoll, Belize, Central America and its conservation significance. Caribbean Journal of Science, 48(1), 71-75.
Flores-Cascante, L., Morales-Vela, B., Castelblanco-Martínez, N., Padilla-Saldívar, J., & Auil, N. (2013). Elementos de la dieta del manatí Trichechus manatus manatus en tres sitios importantes para la especie en México y Belice. Journal of Marine and Coastal Sciences, 5, 25-36.
Gagnon, É. (2023). Multi-Scale Habitat Selection of Antillean Manatees (Trichechus manatus manatus) in Sian Ka’an Biosphere Reserve, Southeastern Mexico (Master dissertation, Université d’Ottawa/University of Ottawa).
Garces Cuartas, N. (2020). Ecología trófica del manatí del Caribe: una herramienta de conservación para ecosistemas estratégicos en el Caribe Mexicano. Tesis de doctorado. Universidad de Quintana Roo. Chetumal, México.
Galves, C. G., Gomez, N. A., Galves, J., Zilliacus, K. M., Croll, D. A., & Kilpatrick, A. M. (2023a). Increasing mortality of Endangered Antillean manatees Trichechus manatus manatus due to watercraft collisions in Belize. Endangered Species Research, 51, 103-113.
Galves, J., Galves, C. G., Gomez, N. A., Bonde, R. K., Powell, J., Alvarez-Alemán, A., & Castelblanco-Martínez, N. (2023b). Analysis of a long-term dataset of Antillean manatee strandings in Belize: implications for conservation. Oryx, 57(1), 80-88.
Hunter, M. E., Auil‐Gomez, N. E., Tucker, K. P., Bonde, R. K., Powell, J., & McGuire, P. M. (2010). Low genetic variation and evidence of limited dispersal in the regionally important Belize manatee. Animal Conservation, 13(6), 592-602.
LaCommare, K. S., Brault, S., Self-Sullivan, C., & Hines, E. M. (2012). Trend detection in a boat-based method for monitoring sirenians: Antillean manatee case study. Biological Conservation, 152, 169-177.
LaCommare, K. S., Self-Sullivan, C., & Brault, S. (2008). Distribution and habitat use of Antillean manatees (Trichechus manatus manatus) in the Drowned Cayes area of Belize, Central America. Aquatic Mammals, 34(1), 35
Machuca-Coronado, O., Quintana-Rizzo, E., Sandoval, T., Corona-Figueroa, M. F., & Garcia, H. A. (2023). Characteristics and spatial identification of Antillean manatee (Trichechus manatus manatus Sirenia: Trichechidae) strandings in Guatemala. Revista de Biología Tropical, 71(S4), e57274-e57274.
Méndez, G., S. Carney, H.A. Garcia, and E. Quintana-Rizzo. Initial characterization of mitochondrial DNA control region haplotypes of the Antillean manatee (Trichechus manatus manatus Sirenia: Trichechidae) in Guatemala. Journal of Tropical Biology and Conservation 71(S4): e57278 https://doi.org/10.15517/rev.biol.trop..v71iS4.57278
Morales-Vela, B., & Bahena-Basave, H. (2023). Manatíes de la costa maya. Chetumal, México. El Colegio de la Frontera Sur. 180 pp.
Morales-Vela, B., Olivera-Gómez, D., Reynolds III, J. E., & Rathbun, G. B. (2000). Distribution and habitat use by manatees (Trichechus manatus manatus) in Belize and Chetumal Bay, Mexico. Biological Conservation, 95(1), 67-75.
Nourisson, C., Morales-Vela, B., Padilla-Saldívar, J., Tucker, K. P., Clark, A., Olivera-Gómez, L. D., … & McGuire, P. (2011). Evidence of two genetic clusters of manatees with low genetic diversity in Mexico and implications for their conservation. Genetica, 139, 833-842.
Quintana-Rizzo, E. (1993). Estimación de la distribución y el tamaño poblacional del manatí Trichechus manatus (Trichechidae-Sirenia) en Guatemala) [Unpublished thesis of Licenciatura]. Universidad San Carlos de Guatemala.
Quintana-Rizzo, E., Machuca-Coronado, O., & Garcia, H. A. (2023). Long-term spatiotemporal distribution, abundance, and priority areas for manatees and calves (Trichechus manatus Sirenia: Trichechidae) in Guatemala. Revista de Biología Tropical, 71(S4), e57273-e57273.
Ramos, E.A., Tellez, M., Castelblanco-Martínez, N., May-Collado, L. (2024). Antillean manatees feed on floating Halophila baillonii in Placencia Lagoon, Belize. Latin American Journal of Aquatic Mammals. doi: 10.5597/lajam00322
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Self-Sullivan, C., Smith, G. W., Packard, J. M., & LaCommare, K. S. (2003). Seasonal occurrence of male Antillean manatees (Trichechus manatus manatus) on the Belize Barrier Reef. Aquatic Mammals, 29(3), 342-354.
Self-Sullivan, C., & Mignucci-Giannoni, A. A. (2012). West Indian manatees (Trichechus manatus) in the wider Caribbean region. Regional issues in Sirenian Conservation.
SEMARNAT (2020). Programa de Acción para la Conservación de la Especie Manatí de las Antillas (Trichechus manatus manatus). SEMARNAT/CONANP, México. 153 pp + Anexos.
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