Registros antigos da presença do Peixe-Boi do Caribe (Trichechus manatus) no Brasil

P.J.P., Whitehead

doi:10.1590/1809-43921978083497

Cited by 11 publications

(2 citation statements)

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“…The low genetic diversity in the Brazilian Antillean manatee may be a combination of a founder effect and the decrease in abundance of manatees due to habitat loss and intensive historical hunting. Despite the decreased abundance due to hunting pressure, no evidence of a bottleneck within the last ∼0.2-4 N E generations (∼32-92 years) was detected using the generation time of 16-23 years (Whitehead, 1978;Vaha and Primmer, 2006). Only approximately five manatee generations (∼100 years) have occurred since indiscriminate hunting was reduced in Brazil which is likely not sufficient to produce a detectable bottleneck in our analyses (Cornuet and Luikart, 1996;Luna et al, 2008bLuna et al, , 2018Luna and Passavante, 2010).…”

Section: Brazilian Manatee Genetic Diversitymentioning

confidence: 92%

“…Only approximately five manatee generations (∼100 years) have occurred since indiscriminate hunting was reduced in Brazil which is likely not sufficient to produce a detectable bottleneck in our analyses (Cornuet and Luikart, 1996;Luna et al, 2008bLuna et al, , 2018Luna and Passavante, 2010). Additionally, the southern and westward colonization of manatees along the coastline of Brazil may have proceeded through a series of bottlenecks, according to population size estimates and records (Whitehead, 1978). The colonization may be too distant in time to be detected with these analytical tools.…”

Section: Brazilian Manatee Genetic Diversitymentioning

confidence: 99%

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Genetic Connectivity of the West Indian Manatee in the Southern Range and Limited Evidence of Hybridization With Amazonian Manatees

et al. 2021

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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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Section: Brazilian Manatee Genetic Diversitymentioning

confidence: 92%

Section: Brazilian Manatee Genetic Diversitymentioning

confidence: 99%

Genetic Connectivity of the West Indian Manatee in the Southern Range and Limited Evidence of Hybridization With Amazonian Manatees

et al. 2021

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Phylogeographic implications for release of critically endangered manatee calves rescued in Northeast Brazil

Luna¹,

Bonde²,

Attademo³

et al. 2012

Aquatic Conservation

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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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Distribution and status of manatees Trichechus spp. Near the mouth of the amazon river, Brazil

Domning

1981

Biological Conservation

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Registros antigos da presença do Peixe-Boi do Caribe (Trichechus manatus) no Brasil

Cited by 11 publications

References 0 publications

Genetic Connectivity of the West Indian Manatee in the Southern Range and Limited Evidence of Hybridization With Amazonian Manatees

Genetic Connectivity of the West Indian Manatee in the Southern Range and Limited Evidence of Hybridization With Amazonian Manatees

Phylogeographic implications for release of critically endangered manatee calves rescued in Northeast Brazil

Distribution and status of manatees Trichechus spp. Near the mouth of the amazon river, Brazil

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