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Borges, João Carlos Gomes; Alves, Leucio Câmara; Lima, Danielle dos Santos; Luna, Fábia de Oliveira; Aguilar, Carla Verônica Carrasco; Vergara-Parente, Jociery Einhardt; Faustino, Maria Aparecida da Glória; Lima, Ana Maria Alves; Marmontel, Miriam
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2007a |
Ocurrencia de Cryptosporidium spp. en manatí amazônico (Trichechus inunguis, Natterer, 1883).
Biotemas 20(3): 63-66. Sept. 2007.
–Engl. summ.
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Luna, Fábia de Oliveira; Bonde, Robert K.; Attademo, Fernanda L. N.; Saunders, Jonathan W.; Meigs-Friend, Gaia; Passavante, José Zanon O.; Hunter, Margaret E.
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2012 |
Phylogeographic implications for release of critically endangered manatee calves rescued in northeast Brazil.
Aquatic Conserv.: Mar. Freshw. Ecosyst. 22(5): 665–672. 2 tabs. 1 fig. DOI: 10.1002/aqc.2260 Publ. online July 4, 2012 in wileyonlinelibrary.com.
–ABSTRACT: 1. The Antillean manatee (Trichechus manatus manatus), a subspecies of the West Indian manatee, is a large-bodied marine mammal found in fresh, brackish, and marine habitats throughout the Caribbean Islands and Central and South America. Antillean manatees in Brazil are classified as critically endangered, with a census size of approximately 500 individuals. The population in the Northeast region of Brazil is suspected to have approximately 300 manatees and is threatened by habitat alteration and incidental entanglement in fishing gear.
2. A high incidence of dependent calf strandings have been identified near areas of altered critical manatee habitat. The majority of the calves are neonates, discovered alive, with no potential mothers nearby. These calves typically require human intervention to survive.
3. Since 1989 the calves have been rescued (N=67), rehabilitated, and released (N=25) to supplement the small wild manatee population. The rescued calves, and those born in captivity, are typically, not released to their rescue location, mainly for logistical reasons. Therefore, phylogeographic analyses can help to identify related populations and appropriate release sites.
4. Here, mitochondrial DNA analyses identified low haplotype (h=0.08) and nucleotide (p=0.0026) genetic diversity in three closely related haplotypes. All three haplotypes (M01, M03, and a previously unidentified haplotype, M04) were found in the northern portion of the region, while only a single haplotype (M01) was represented in the south. This suggests the presence of two genetic groups with a central mixing zone. Release of rehabilitated calves to unrelated populations may result in genetic swamping of locally adapted alleles or genotypes, limiting the evolutionary potential of the population.
5. The small population size coupled with low genetic diversity indicates that the Northeast Brazil manatee population is susceptible to inbreeding depression and possible local extinction. Further conservation measures incorporating genetic information could be beneficial to the critically endangered Brazilian manatee population.
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Normande, Iran C.; Malhado, Ana C. M.; Reid, J.; Viana, P. C.; Savaget, P. V. S.; Correia, Richard A.; Luna, Fábia de Oliveira; Ladle, Richard James
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2015 |
Post-release monitoring of Antillean manatees: an assessment of the Brazilian rehabilitation and release programme.
Animal Conservation 19: 235–246. DOI: 10.1111/acv.12236. Published online September 22, 2015.
–ABSTRACT: Mammalian reintroduction programmes frequently aim to reconnect isolated sub-populations and restore population viability. However, these long-term objectives are rarely evaluated due to the inadequacy of post-release monitoring. Here, we report the results of a unique long-term telemetry-based monitoring programme for rehabilitated Antillean manatees Trichechus manatus manatus reintroduced into selected sites in north-east Brazil with the aim of reconnecting isolated relict populations. Twenty-one satellite-tagged rehabilitated manatees, 13 males and 8 females, were released into the wild from two sites between November 2008 and June 2013. Individual accumulation curves were plotted and home ranges were calculated through the fixed kernel method using 95% of the utilization distribution. The number and size of the centres of activity (COAs) were calculated using 50% of the utilization distribution. Manatees displayed a dichotomous pattern of movement, with individuals either characterized by sedentary habits or by much more extensive movements. Moreover, home-range size was not significantly influenced by gender, age at release or release site. COAs were strongly associated with sheltered conditions within reefs and estuaries, and also by the presence of freshwater and feeding sites. Our data confirm that manatee reintroductions in Brazil have the potential to reconnect distant sub-populations. However, pre-release identification of potential long-distance migrants is currently unfeasible, and further analysis would be required to confirm genetic mixing of distant sub-populations.
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Normande, Iran Campello; Luna, Fabia De Oliveira; Mendes Malhado, Ana Claudia; Gomes Borges, Joao Carlos; Viana Junior, Pitagoras Carlos; Niemeyer Attademo, Fernanda Loeffer; Ladle, Richard J.
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2015 |
Eighteen years of Antillean manatee Trichechus manatus manatus releases in Brazil: lessons learnt.
Oryx 49(2): 338-344. 1 tab. 2 figs. 1 pl. DOI: 10.1017/S0030605313000896. April 2015.
–ABSTRACT: The Antillean manatee Trichechus manatus manatus was once widespread from the south-eastern coast of Brazil to Central America and the Caribbean. In Brazil habitat destruction and overhunting severely reduced and fragmented the wild population, restricting extant subpopulations to the north and north-east coast. In response to these threats an ambitious government-led programme was initiated in 1994, with the aim of rehabilitating orphaned manatee calves and releasing them into the southernmost subpopulation. The programme is unique within Brazil, and has invested unprecedented resources in post-release monitoring. So far 30 manatees have been released at three sites, with a high rate of success (> 75%). Time in captivity appears to be a key variable determining post-release success: too long or too short a time in captivity decreasing the probability of survival. We describe the main features of this long-term programme and identify six key lessons learnt: (1) close monitoring, health assessments and rescues can significantly increase the success of releases, (2) combining different monitoring techniques results in high-quality data and reduces tracking costs, (3) long-term studies are needed to effectively evaluate the results, (4) releasing manatees at c. 5 years of age can increase chances of success, (5) soft-release is important to aid acclimatization, and (6) the programme has been effective in raising awareness among the general public, supporting education and fund-raising.
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Luna, Fábia de Oliveira; Beaver, Caitlin E.; Nourisson, Coralie; Bonde, Robert K.; Attademo, Fernanda L. N.; Miranda, Adriana Vieira; Torres-Florez, Juan Pablo; Sousa, Glaucia Pereira de; Passavante, José Zanon; Hunter, Margaret E.
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2021 |
Genetic connectivity of the West Indian Manatee in the southern range and limited evidence of hybridization with Amazonian manatees.
Front. Mar. Sci. 7: 574455. 4 tabs. 4 figs. + online supplementary material. https://doi.org/10.3389/fmars.2020.574455 Jan. 6, 2021.
–ABSTRACT: The Antillean subspecies of the West Indian manatee is classified as endangered by the International Union for the Conservation of Nature (IUCN) Red List. In Brazil, the manatee population is listed as endangered with an estimated population size of 500–1,000. Historic hunting, recent habitat degradation, and fisheries bycatch have decreased the population size. The Amazonian manatee is listed as vulnerable by the IUCN with unknown population sizes within Brazil. The Antillean manatee occurs in sympatry with the Amazonian manatee in Brazil and hybridization has been previously indicated. To provide information on the genetic structure, diversity, and degree of hybridization in the sympatric zone near the Amazon River mouth, the mitochondrial DNA control region and 13 nuclear microsatellite markers were assessed on the two species. Samples were analyzed from the Antillean subspecies across its distribution in Brazil (n = 78) and from the Amazonian species (n = 17) at the Amazon River mouth and inland mainstem river. To assess the previously defined evolutionary significant units of Antillean manatees in the area, an additional 11 samples from Venezuela and Guyana were included. The Antillean manatee was found to be a single population in Brazil and had lower than average number of alleles (3.00), expected heterozygosity (0.34), and haplotype diversity (0.15) when compared to many other manatee populations. The low values may be influenced by the small population size and extended pressures from anthropogenic threats. Gene flow was identified with Venezuela/Guyana in admixed Antillean Brazil samples, although the two populations were found to be moderately divergent. The nuclear loci in Venezuela/Guyana Antillean manatee samples indicated high differentiation from the samples collected in the Amazon River (FST = 0.35 and RST = 0.18, p = 0.0001). No indication of nuclear hybridization was found except for a single sample, "Poque" that had been identified previously. The distribution of Antillean manatees in Brazil is extensive and the areas with unique habitat and threats would benefit from independent management and conservation actions. Gene flow, resulting in genetic diversity and long-term population stability, could be improved in the southern range through habitat restoration, and the establishments of travel corridors and protected areas, which are particularly important for successful parturition and neonatal calf survival.
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