Aquatic Mammals 2017, 43(2), 201-207, DOI 10.1578/AM.43.2.2017.201 Is the West Indian Manatee (Trichechus manatus) at the Brink of Extinction in the State of Veracruz, Mexico? Arturo Serrano, 1 Iliana del Carmen Daniel-Rentería, 1 Tania Hernández-Cabrera, 1 Gerardo Sánchez-Rojas, 2 Liliana Cuervo-López, 1 and Agustín Basáñez-Muñoz 1 1 Laboratorio de Mamíferos Marinos, Universidad Veracruzana, Km 7.5 Carretera Tuxpan-Tampico, CP 92850, Tuxpan, Veracruz, México E-mail: arserrano@uv.mx 2 Centro de Investigaciones Biológicas, Universidad Autónoma del Estado de Hidalgo, Km 4.5 Carretera Pachuca Tulancingo, Pachuca, Hidalgo, CP 42184, México Abstract species, which is often associated with habitats warmer than 24° C (Whitehead, 1977; Edwards, The West Indian manatee (Trichechus mana- 2013; Kleen & Breland, 2014). The current distri- tus) is distributed from the Atlantic coast of the bution of West Indian manatees is fragmented, and United States to the center of Brazil along the the species is less abundant than in the past century. Atlantic Ocean, Caribbean Sea, and Gulf of This decline in abundance is mainly due to uncon- Mexico. The species’ current distribution is more trolled hunting and habitat loss (Powell, 1996). This fragmented than in the past, and manatee popula- species is designated as threatened with extinc- tions are generally less abundant than they were tion by the Convention on International Trade in during the last century. In Mexico, there is no Endangered Species (CITES) (2008), vulnerable by specific information about the size of the manatee the International Union for Conservation of Nature populations. Hence, the objective of this study was and Natural Resources (IUCN) (2008), and threat- to estimate the density and abundance of manatees ened with extinction by the Secretaría del Medio in the Alvarado Lagoon System (ALS) in Veracruz Ambiente y Recursos Naturales (SEMARNAT) using distance sampling. In total, 959 systematic (2010). line transects were surveyed using a small boat. The overall status of manatees in Mexico These surveys covered 90% of the ALS. Manatee is unknown (United Nations Environment density and abundance for the entire ALS was Programme [UNEP], 2010). Based on empirical estimated at 0.23 animals/km 2 (CV 34.48%) and data, some authors have suggested that there are 121 manatees (CV 34.48%), respectively. These about 1,000 to 2,000 manatees in Mexico (UNEP, are the first density and abundance estimates for 2010). A few local populations have been stud- this lagoon system and for the State of Veracruz. ied—for example, approximately 250 manatees The extremely low number of manatees supports have been estimated for the State of Quintana Roo the urgent implementation of effective conserva- (Colmenero & Zárate, 1990; Morales-Vela et al., tion measures for the species to prevent extinction 2000). The other states with manatee populations of this species in Veracruz. have no precise data on the abundance of this species. Key Words: West Indian manatee, Trichechus Manatees have been reported along the entire manatus manatus, abundance, density, Veracruz, coast of the State of Veracruz (Colmenero & conservation, coastal management, Gulf of Hoz, 1986); however, recent studies proved that Mexico, Sirenia the species has disappeared from the north of the state (Serrano et al., 2007). The largest and most Introduction preserved manatee population in Veracruz may be in the Alvarado Lagoon System (ALS) (Ortega- The West Indian manatee (Trichechus mana- Argueta et al., 2003). Therefore, the purpose of tus) is distributed from the Atlantic coast of the this study was to estimate the density and abun- United States to the center of Brazil along the dance of manatees in the ALS to obtain baseline Atlantic Ocean, Caribbean Sea, and Gulf of Mexico data which can be compared to other manatee (Lefebvre et al., 2001). Water temperature is one of populations in Mexico and allow for long-term the key factors influencing the distribution of this assessments of this population in Veracruz.