Showing papers by "Vera M. F. da Silva published in 2018"

Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades.

Abstract: Obligate river dolphins occur only in the rivers of Asia and South America, where they are increasingly subject to damaging pressures such as habitat degradation, food competition and entanglement in fishing gear as human populations expand. The Amazon basin hosts two, very different, dolphins-the boto or Amazon river dolphin (Inia geoffrensis) and the smaller tucuxi (Sotalia fluviatilis). Both species have wide geographical ranges and were once considered to be relatively abundant. Their IUCN Red List conservation status of Data Deficient (DD), due to limited information on threats, ecology, population numbers and trends, did not initially cause alarm. However, the development of dolphin hunting to provide fish bait at around the beginning of this millennium broadly coincided with the onset of a widespread perception that numbers of both species were in decline. Consequently, the need for population trend data to inform conservation advice and measures became urgent. This paper presents a 22-year time series of standardised surveys for both dolphins within the Mamiraua Reserve, Amazonas State, Brazil. Analysis of these data show that both species are in steep decline, with their populations halving every 10 years (botos) and 9 years (tucuxis) at current rates. These results are consistent with published, independent information on survival rates of botos in this area, which demonstrated a substantial drop in annual survival, commencing at around the year 2000. Mamiraua is a protected area, and is subject to fewer environmental pressures than elsewhere in the region, so there is no reason to suspect that the decline in dolphins within the Reserve is more pronounced than outside it. If South America's freshwater cetaceans are to avoid following their Asian counterparts on the path to a perilous conservation status, effective conservation measures are required immediately. Enforcement of existing fishery laws would greatly assist in achieving this.

Sotalia dolphins in their potential sympatry zone: searching for hybrids in the Amazonian estuary

Abstract: The two Sotalia species (the marine S. guianensis and the freshwater S. fluviatilis) have only recently been recognized, and both face several conservation challenges. We investigated the existence of hybridization between the two species in their possible area of sympatry in the Amazon Estuary, in northern Brazil. A fast and cheap PCR-RFLP diagnostic method using nuclear DNA was developed to discriminate between the two species, while allowing the detection of hybrids. All samples that could be identified (N = 51) were identified as S. guianensis, and no hybrids were detected. Our results, coupled with previous mitochondrial data, suggest that S. fluviatilis is not present in the Amazon delta. Thus, sympatry with S. guianensis, if it does occur, may be restricted to upstream areas of the Amazon River.

Commercial feed acceptance of diets for Amazonian manatees (Trichechus inunguis) in captivity

Abstract: Keeping Amazonian manatees ( Trichechus inunguis ) in captivity is expensive and complex. Access to natural food is seasonal, and feeding manatees farmed plants is quite costly, requiring expensive logistics and planning. This study aimed to obtain alternative, good-quality feed to reduce feeding costs and decrease the risk of infectious and contagious diseases transmitted by contaminated food. The experiment was conducted in two stages: an acceptance test and a palatability test. Four adult animals in good health were used, two males and two females. Two types of extruded commercial feed were tested, one specific for horses and the other for laboratory rodents. During the experiment, the body and health status of the animals were monitored by biometrics and complete blood counts. The animals studied behaved favorably toward the introduction of the new feed and maintained satisfactory health status and body mass, considering the stressful conditions to which they were subjected. The two females were less receptive to the new feed, and the ration size directly affected intake because larger diameter pellets are more easily captured by the prehensile lips of T. inunguis . Captive Amazonian manatees accept the addition of concentrate to their diet as long as the size is conducive to capturing the pellets.

CARACTERIZAÇÃO DE AMINOÁCIDOS NA Bertholletia excelsa: VIABILIDADE NUTRICIONAL PARA INCORPORAÇÃO NA DIETA DE FILHOTES DE PEIXE-BOI DA AMAZÔNIA EM CATIVEIRO

Abstract: A maioria dos filhotes de Trichechus inunguis orfaos que chegam aos centros de pesquisa e reabilitacao e lactante. Essa condicao dificulta o processo de reabilitacao, sendo necessario oferecer uma dieta lactea artificial adequada. Com o intuito de incrementar o teor de aminoacidos no sucedâneo lacteo buscou-se dentre os alimentos habitualmente amazonicos um ingrediente capaz de fornecer os nutrientes necessarios para potencializar o sucedâneo utilizado, sendo facilmente adquiro, apresentar alto valor biologico, rapida manipulacao, perecibilidade reduzida e baixo custo de obtencao. Dentre os alimentos que preenchem esses pre-requisitos, destaca-se a castanha-do-Brasil. Avaliou-se neste estudo a viabilidade nutricional em termos de aminoacidos da Bertholletia excelsa, para a possivel suplementacao no sucedâneo lacteo fornecido aos filhotes de peixe-boi da Amazonia em cativeiro. As amendoas foram descascadas, maceradas e em seguida foi pesado 27 mg, digerido em HCl 6 M, aquecido a 150 o C por 90 minutos e analisado por Cromatografia Liquida de Alta Eficiencia por troca ionica. Os resultados demonstraram uma concentracao elevada de aminoacidos nao essenciais, dentre eles arginina e acido glutâmico + glutamina. Os aminoacidos em menor concentracao foram prolina, alanina e tirosina. Dentre os aminoacidos essenciais, a valina e a leucina apresentaram as maiores concentracoes, entretanto os aminoacidos menos abundantes foram a histidina, isoleucina. Os demais aminoacidos apresentaram teores equivalentes na analise da composicao em aminoacidos da castanha. Concluiu-se nesse trabalho que a castanha do Brasil e uma fonte potencial de enriquecimento nutricional na dieta lactea de filhotes de T.inunguis em cativeiro.