<p>Antillean manatees (Trichechus manatus manatus) were heavily hunted in the past throughout the Wider Caribbean Region (WCR), and are currently listed as endangered on the IUCN Red List of Threatened Species. In most WCR countries, including Haiti and the Dominican Republic, remaining manatee populations are believed to be small and declining, but current information is needed on their status, distribution, and local threats to the species.</p><p>To assess the past and current distribution and conservation status of the Antillean manatee in Hispaniola, I conducted a systematic review of documentary archives dating from the pre-Columbian era to 2013. I then surveyed more than 670 artisanal fishers from Haiti and the Dominican Republic in 2013-2014 using a standardized questionnaire. Finally, to identify important areas for manatees in the Dominican Republic, I developed a country-wide ensemble model of manatee distribution, and compared modeled hotspots with those identified by fishers.</p><p>Manatees were historically abundant in Hispaniola, but were hunted for their meat and became relatively rare by the end of the 19th century. The use of manatee body parts diversified with time to include their oil, skin, and bones. Traditional uses for folk medicine and handcrafts persist today in coastal communities in the Dominican Republic. Most threats to Antillean manatees in Hispaniola are anthropogenic in nature, and most mortality is caused by fisheries. I estimated a minimum island-wide annual mortality of approximately 20 animals. To understand the impact of this level of mortality, and to provide a baseline for measuring the success of future conservation actions, the Dominican Republic and Haiti should work together to obtain a reliable estimate of the current population size of manatees in Hispaniola.</p><p> </p><p>In Haiti, the survey of fishers showed a wider distribution range of the species than suggested by the documentary archive review: fishers reported recent manatee sightings in seven of nine coastal departments, and three manatee hotspot areas were identified in the north, central, and south coasts. Thus, the contracted manatee distribution range suggested by the documentary archive review likely reflects a lack of research in Haiti. Both the review and the interviews agreed that manatees no longer occupy freshwater habitats in the country. In general, more dedicated manatee studies are needed in Haiti, employing aerial, land, or boat surveys. </p><p>In the Dominican Republic, the documentary archive review and the survey of fishers showed that manatees still occur throughout the country, and occasionally occupy freshwater habitats. Monte Cristi province in the north coast, and Barahona province in the south coast, were identified as focal areas. Sighting reports of manatees decreased from Monte Cristi eastwards to the adjacent province in the Dominican Republic, and westwards into Haiti. Along the north coast of Haiti, the number of manatee sighting and capture reports decreased with increasing distance to Monte Cristi province. There was good agreement among the modeled manatee hotspots, hotspots identified by fishers, and hotspots identified during previous dedicated manatee studies. The concordance of these results suggests that the distribution and patterns of habitat use of manatees in the Dominican Republic have not changed dramatically in over 30 years, and that the remaining manatees exhibit some degree of site fidelity. The ensemble modeling approach used in the present study produced accurate and detailed maps of manatee distribution with minimum data requirements. This modeling strategy is replicable and readily transferable to other countries in the Caribbean or elsewhere with limited data on a species of interest.</p><p>The intrinsic value of manatees was stronger for artisanal fishers in the Dominican Republic than in Haiti, and most Dominican fishers showed a positive attitude towards manatee conservation. The Dominican Republic is an upper middle income country with a high Human Development Index. It possesses a legal framework that specifically protects manatees, and has a greater number of marine protected areas, more dedicated manatee studies, and more manatee education and awareness campaigns than Haiti. The constant presence of manatees in specific coastal segments of the Dominican Republic, the perceived decline in the number of manatee captures, and a more conservation-minded public, offer hope for manatee conservation, as non-consumptive uses of manatees become more popular. I recommend a series of conservation actions in the Dominican Republic, including: reducing risks to manatees from harmful fishing gear and watercraft at confirmed manatee hotspots; providing alternative economic alternatives for displaced fishers, and developing responsible ecotourism ventures for manatee watching; improving law enforcement to reduce fisheries-related manatee deaths, stop the illegal trade in manatee body parts, and better protect manatee habitat; and continuing education and awareness campaigns for coastal communities near manatee hotspots. </p><p>In contrast, most fishers in Haiti continue to value manatees as a source of food and income, and showed a generally negative attitude towards manatee conservation. Haiti is a low income country with a low Human Development Index. Only a single dedicated manatee study has been conducted in Haiti, and manatees are not officially protected. Positive initiatives for manatees in Haiti include: protected areas declared in 2013 and 2014 that enclose two of the manatee hotspots identified in the present study; and local organizations that are currently working on coastal and marine environmental issues, including research and education on marine mammals. Future conservation efforts for manatees in Haiti should focus on addressing poverty and providing viable economic alternatives for coastal communities. I recommend a community partnership approach for manatee conservation, paired with education and awareness campaigns to inform coastal communities about the conservation situation of manatees in Haiti, and to help change their perceived value. Haiti should also provide legal protection for manatees and their habitat.</p> / Dissertation

Belize has been identified as an important location for Antillean manatees (Trichechus manatus manatus), harboring the highest known population density of this subspecies. Information about their dietary habit is important in determining habitat requirements and aiding in conservation efforts. The main objective of this study was to identify the key plant species consumed by manatees in Belize and to establish differences in diet based on location, sex, size classification, and season. Samples were collected from two different locations within Belize where manatees are known to aggregate: Southern Lagoon and the Drowned Cayes off of Belize City. The contents of thirteen mouth, six digestive tract (stomach, duodenum and colon), and 124 fecal samples were analyzed. Five species of seagrasses (Halodule wrightii, Thalassia testudinum, Ruppia maritima, Syringodium filiforme, and Halophila sp.) made up the highest percentage of plants consumed; undigested rhizome was most prevalent. A vascular plant, the red mangrove (Rhizophora mangle), was identified as an important food item of manatees in Belize. Algae (Chara sp., Lyngbia sp., and Ulvasp.) and invertebrates (diatoms and sponges) were represented as well. These items are comparable to other reports of manatee diets in areas near Belize and areas with similar habitat. Variation in the percentage of seagrass, mangrove, and algae consumption was analyzed as a 4-factor factorial Analysis of Variance (ANOVA) with main effects and interactions for locality (Southern Lagoon and the Drowned Cayes), sex, size classification (>245 cm & ˂245 cm), and season (December – May and June – November). Sex and season did not influence diet composition; differences for locality and size classification were observed. Seagrass was more often consumed in Southern Lagoon (P = 0.03), whereas mangroves and algae were more prevalent in the Drowned Cayes (P = 0.03). No differences among size classifications in consumption of seagrasses or mangroves were observed. A significantly higher number of samples from adults (>245 cm) than juveniles (˂245 cm) contained algae (P = 0.04). This is most likely attributed to inexperience in foraging. Findings from these results suggest that diet composition analysis can be used to interpret Antillean manatee habitat and resource utilization and can aid in the conservation of this endangered species.

<p>Manatees (Mammalia: Sirenia), along with the closely related dugongs, are the only herbivorous marine mammals. Manatees consume a wide variety of vascular plants and algae in both marine and freshwater habitats. However, little is known about what characteristics influence diet and food selectivity, especially in freshwater habitats, which represent a large portion of the available habitat for the endangered Antillean manatee, <italic>Trichechus manatus manatus</italic>, in Central and South America. Understanding foraging ecology is an important element of effective conservation strategies.</p><p>This dissertation investigated various aspects of the foraging ecology of the Antillean manatee in a freshwater habitat, specifically: 1) how plant availability (i.e. species richness, diversity, and abundance) varied seasonally with changes in water depths, 2) manatee food selectivity from a representative set of plant species from that freshwater habitat, and 3) the relationship of plant nutritive compounds and availability with manatee food selectivity. In addition, this dissertation describes the multiple uses of sonar technology for studying manatees and habitat characteristics in freshwater.</p><p>Plant availability to manatees was evaluated by conducting monthly plant surveys from July 2010-July 2011 in four contact lakes in the wetlands of Tabasco, Mexico. Manatee food selectivity was examined by conducting food selection experiments on a wild adult manatee during the low water season with 54 plant species representing 25+ genera. The nutritive components (i.e. crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HC), and ash) and plant availability values for selected and non-selected plants species were evaluated to determine their relationship with manatee food selectivity. The applicability of using side-scan sonar for manatee research was tested in various freshwater and estuarine habitats in Honduras, Costa Rica, Panama, and the wetlands of Tabasco, Mexico between 2006-2011.</p><p>The major findings of this dissertation are as follows. Plant species richness, diversity, and abundance were greatest during the rising water season (July-August) and lowest during the low water season (March-June). No plants were available in April-June, which represented the majority of the low water season. The wild manatee</p><p>selected 27 (11+ genera) of the 54 species examined during the feeding experiments. Of the plant characteristics tested (i.e. nutritive components and plant availability), only digestible fiber (HC) was significantly related to manatee food selection, with manatees</p><p>selecting plants with higher HC content. Four unique applications were identified for the use of side-scan sonar to facilitate manatee research in freshwater habitats: 1) confirmation of visual sightings and determination of group size, 2) determination of mother-calf pairs, 3) habitat characterization, and 4) assisting manatee captures.</p><p>Results from this study reveal that manatees living in the freshwater wetlands of Tabasco, Mexico have to cope with a highly seasonal availability of plants and that while manatees consume plants from a wide variety of genera, they are highly selective. Unlike other herbivorous mammals, manatee food selectivity was not influenced by CP, NDF, or ADF, but rather by digestible fiber. A unique suit of anatomical and physiological characteristics suggests that manatees may be fiber digestion specialists. Both seasonal plant availability and the manatee's large dietary breadth must be considered when developing 1) conservation strategies for wild manatees in freshwater habitats and 2) protocols for captive rehabilitation of orphaned and stranded manatees that will be reintroduced into the wild.</p> / Dissertation

O peixe-boi marinho, Trichechus manatus manatus, à um mamÃfero com dieta herbÃvora, e distribuiÃÃo costeira em rios, estuÃrios e Ãguas litorÃneas da Zona Tropical brasileira. No Estado do Cearà ocorre em duas Ãreas distintas, no extremo dos seus setores leste e oeste. No litoral leste nÃo existe nenhuma Unidade de ConservaÃÃo com abrangÃncia marinha que restrinja os impactos causados ao meio ambiente e à populaÃÃo do peixe-boi, tais como urbanizaÃÃo, turismo e ocupaÃÃo de praias, dunas, falÃsias e manguezais. Sendo considerado pela UniÃo Internacional para ConservaÃÃo da Natureza como âespÃcie vulnerÃvelâ e estando inserido na Lista Oficial de EspÃcies da Fauna Brasileira AmeaÃadas de ExtinÃÃo de acordo com o IBAMA, corre risco de extinÃÃo extremamente alto num futuro prÃximo. Os objetivos desta DissertaÃÃo foram determinar a distribuiÃÃo espacial e padrÃes de uso da Ãrea, escolha da metodologia mais adequada ao monitoramento da populaÃÃo, e realizar levantamento das Ãreas de alimentaÃÃo e fontes e Ãgua doce provavelmente utilizadas pelos animais. A base de dados foi obtida atravÃs de prospecÃÃes aÃrea, realizada de junho/2003 a outubro/2004, totalizando 11 sobrevÃs e 24 horas de esforÃo de monitoramento, e nÃutica, realizada de agosto/2003 a novembro/2004, num total de 10 embarques e 157 horas de esforÃo de monitoramento. Dentre os mÃtodos de prospecÃÃo aÃrea e nÃutica, o primeiro gera erros devido à turbidez da Ãgua, e dificuldades de identificaÃÃo e contagem dos indivÃduos, enquanto o segundo, por sua maior proximidade em relaÃÃo aos animais, mostrou-se mais eficiente. O status da populaÃÃo do peixe-boi marinho foi avaliado atravÃs dos seguintes parÃmetros: (a) conservaÃÃo do habitat, com Ãnfase para a manutenÃÃo do territÃrio; (b) acesso a fontes de Ãgua doce e a Ãreas preferenciais de alimentaÃÃo e reproduÃÃo; (c) geraÃÃo de condiÃÃes ambientais Ãtimas para os cuidados parentais. Os fatores de ameaÃa de extinÃÃo nessa Ãrea estariam relacionados com reduÃÃo das fontes de alimento e Ãgua doce, assoreamento do Rio Jaguaribe, alÃm de captura acidental por aparelhos de pesca. Estes se traduzem nas seguintes conseqÃÃncias: reduÃÃo do habitat; aumento da frequÃncia de encalhes de recÃm-nascidos; aumento da mortalidade de adultos. A regiÃo de Picos, com destaque para o Banco dos Cajuais, foi definida como Zona de Alta Densidade, com padrÃo de distribuiÃÃo âaltamente agregadaâ por causa da abundÃncia de macroalgas e do menor fluxo de barcos motorizados. Dentre as recomendaÃÃes para se minimizar os riscos de extinÃÃo do peixe-boi, destacam-se: (a) desenvolvimento de campanhas educacionais que ressaltem aspectos importantes da conservaÃÃo do ambiente marinho; (b) reintroduÃÃo de espÃcimes em locais onde o declÃnio populacional à evidente; (c) criaÃÃo de unidades de conservaÃÃo com abrangÃncia marinha e aplicaÃÃo e fiscalizaÃÃo da legislaÃÃo pertinente ao habitat do peixe-boi e (d) monitoramento sistemÃtico da populaÃÃo no litoral leste para determinaÃÃo dos padrÃes ambientais que influenciam na ocorrÃncia do peixe-boi no municÃpio de IcapuÃ, litoral leste do CearÃ. / The Antillean manatee, Trichechus manatus manatus, is a mammal with an herbivorous diet and costal distribution in rivers, estuaries and inshore waters of the Brazilian Tropical Zone. In Cearà State, the species may found in the outermost ends of its western and eastern sectors. In the eastern sector there are no Marine Conservation Units to ward off impacts to the environment and the manatee population, such as urban development, tourism and occupation of beaches and mangrove forests. Manatees have been classified by the International Union for Nature Conservation as a âvulnerable speciesâ and included on the Official List of Endangered Species of the Brazilian Fauna. According to the Brazilian Institute for the Environment, it runs an extremely high risk of extinction in the near future. The objectives of this Thesis have been to determine the spatial distribution and patterns of usage of the living area, choice of the most appropriate methodology for population monitoring and mapping of feeding grounds and freshwater sources likely to used by the animals. The database was obtained by means of aerial surveys from June, 2003 to October, 2004, making up a 24-hour monitoring effort during 11 overhead flights, as well as nautical surveys performed from August, 2003 to November, 2004, making up a 157-hour monitoring effort during 10 voyages. Of the two prospecting techniques, the aerial one was less practical because of water turbidity, which made it difficult to identify and count manatee specimens, whereas the nautical one, because of its nearness to the targets, proved to the most efficient. The status of the Antillean manatee population was evaluated through the following parameters: (a) habitat conservation, with emphasis on territory maintenance; (b) access to freshwater sources and areas suitable for feeding and reproduction; (c) yielding of optimum environmental conditions for parental care. The threatened extinction in the studied area is related to factors such as decreasing of food and freshwater sources, silting-up of the Jaguaribe River, by-catch by trawl and gillnet fishing. The worrying outcome of such a scenario is likely to result in a reduction of the habitat size; increase in the straying of newborns plus an increase in adult mortality rates. The Picos region, specially the Cajuais sandbank, was defined as a High Density Zone, which displays a highly aggregate distribution because of seaweed abundance and smaller deployment of fishing boats. Among the suggestions for lowering the extinction risks of the Antillean manatee in Eastern Cearà State, the following ones stand out; (a) development of education campaigns which deal with the main aspects of environment preservation; (b) reintroduction of specimens in zones where population decline is evident; (c) installation of Marine Conservation Units and enforcement of the pertinent management measures and (d) constant monitoring of the population in the known habitat to determine environmental patterns which influence manatees in Icapuà county, eastern Cearà State.