943 resultados para mangrove crab


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Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei. © 2013 Sociedade Brasileira de Zoologia All rights reserved.

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The relative growths of Persephona lichtensteinii, P. mediterranea, and P. punctata were investigated on the south-eastern Brazilian coast, focusing on differences in the growth rates between immature and mature phases, the onset of morphological sexual maturity, and the breeding seasons of these species. Crabs were collected every two months from January 1991 through to November 1992, from a shrimp fishing boat equipped with two otter-trawl nets. Significant differences in the patterns of body growth were observed between immature and mature phases of all three species. Changes in the growth rates of the chelipeds (males) and abdomen (females) observed for P. lichtensteinii, P. mediterranea, and P. punctata, seem to be related to the puberty moult for both sexes. Males of P. mediterranea and P. punctata reached larger mean sizes of carapace width than females, whereas no difference was recorded for P. lichtensteinii. The body size at which 50% of males attained sexual maturity was also larger in P. mediterranea and P. punctata, and smaller in P. lichtensteinii. The absence of a pronounced sexual dimorphism and the size at the onset of sexual maturity observed only for P. lichtensteinii might be explained by distinct reproductive strategies of males. The presence of ovigerous females during the entire sampling period suggests that all three species have a continuous reproduction pattern at the Ubatuba region. Future studies on the population structure, functional maturity, and mating system should improve the understanding of factors driving the biology and ecology of these species at a subtropical region. © Marine Biological Association of the United Kingdom 2013.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Geociências e Meio Ambiente - IGCE

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Pós-graduação em Geociências e Meio Ambiente - IGCE

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Pós-graduação em Geociências e Meio Ambiente - IGCE

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This report analyses the agriculture, coastal and human settlements and health sectors in Guyana to assess the potential economic impacts of climate change. The fundamental aim of this report is to assist with the development of strategies to deal with the potential impact of climate change on Guyana. It also has the potential to provide essential input for identifying and preparing policies and strategies to help bring the Caribbean sub-region closer to solving problems associated with climate change and attaining national and regional sustainable development goals. Some of the key anticipated manifestations of climate change for the Caribbean include elevated air and sea-surface temperatures, sea-level rise, possible changes in extreme events and a reduction in freshwater resources. The economic impact of climate change on the three sectors was estimated for the A2 and B2 IPCC scenarios until 2050 (agriculture and health sectors) and 2100 (coastal and human settlements sector). An exploration of various adaptation strategies was also undertaken for each sector using standard evaluation techniques. The study of the impact of climate change on the agriculture sector focused on three leading sub-sectors namely: sugar-cane, rice-paddy and fisheries. In estimating costs, the sugar sub-sector is projected to experience losses under A2 between US$ 144 million (at 4% discount rate) and US$300 million (1% rate); comparative statistics for rice are US$795 million and US$1577 million, respectively; while for fisheries, the results show that losses range from US$15 million (4% rate) and US$34 million (1% rate). In general, under the B2 scenarios, there are gains for sugar up to 2030 under all three discount rates while for rice the performance is somewhat better with gains realized under all three discount rates up to 2040. For fisheries, gains are forecasted under all three rates up to 2050, following marginal losses to 2020. In terms of the benefit-cost analysis conducted on selected adaptation measures under the A2 scenario, there were net benefits for all three commodities under all three discount rates. For the sugar-cane sub-sector these are: drainage and irrigation upgrade, purchase of new machinery for planting and harvesting, developing and replanting climate tolerant sugar-cane. The rice-paddy sub-sector will benefit from adaptive strategies, which include maintenance of drainage and irrigation systems, research and development, as well as education and training. Adaptation in the fisheries sub-sector must include measures such as, mangrove development and restoration and public education. The analysis of the coastal and human settlements sector has shown that based upon exposed assets and population, SLR can be classified as having the potential to create catastrophic conditions in Guyana. The main contributing factor is the concentration of socioeconomic infrastructure along the coastline in vulnerable areas.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)