957 resultados para Atlantic Coast


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Includes bibliography

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Faunal impoverishment and distorted species compositions are common phenomena in oceanic islands; however, many land-bridge islands are poorly inventoried, especially in the Neotropics. We sampled a small mammal community on a land-bridge island (Anchieta Island) along the Brazilian coast. We found only one marsupial Didelphis aurita (Wied-Neuwied, 1826) and two rodent species Oligoryzomys nigripes (Olfers, 1818) and Trinomys iheringi (Thomas, 1911) during 12 months of live trapping and 9195 trap-nights. The diversity of rodents and marsupials was not explained by species-area relations, indicating possible past extinctions. The abundance of D. aurita and O. nigripes was approximately three times higher, while the abundance of T. iheringi was approximately four times lower than abundances reported from other Brazilian Atlantic Forest sites. The population of D. aurita exhibited many phenotypic changes; males were on average 8 % smaller and females produced 30 % less litters than those from the mainland and other land-bridge islands. The long history of forest disturbance, habitat loss, reduction in forest productivity, and the recent introduction of mesopredators may be the major drivers that explain the small mammal community composition on this island. © 2013 Walter de Gruyter GmbH, Berlin/Boston.

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The acoupa weakfish (Cynoscion acoupa - Sciaenidae) is a marine species of croaker with estuarine-dependent behavior, found in the western Atlantic from Panama to Argentina. It is one of the most exploited food fish on the northern coast of Brazil. In this study, DNA sequences were determined from the entire control region (D-loop) of the mitochondrial genome of 297 individuals collected during seven different months between December 2003 and August 2005 on the northern coast of Brazil (Amapá and Pará). Genetic variability expressed by haplotype (h = 0,892) and nucleotide (p = 0,003) diversities were low compared to other heavily exploited marine fish species from the western Atlantic and eastern Asia. AMOVA depicted a lack of genetic structuring among the samples from different years, indicating the presence of a single stock of C. acoupa within the sample area. The possible reasons for the low levels of genetic diversity are discussed. These results demonstrate a need for the monitoring of C. acoupa harvesting and the preservation of the estuaries within its geographic range, considering that this large fish depends on estuarine ecosystems during part of its life cycle.

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Scomberomorus cavalla é uma espécie de peixe pelágico amplamente distribuído na costa oeste do Atlântico, e uma diminuição no seu nível de captura tem sido verificada nos E.U.A e Golfo do México, comparada com os níveis alcançados pela espécie no passado. Da mesma forma, em algumas áreas do Brasil, há indícios de sobre-exploração. Entretanto, não existem estudos moleculares que visam o manejo deste importante item. Desta forma, no presente estudo, foram seqüenciados 380 pares de bases nucleotídicas da região da Alça-D do DNA mitocondrial de amostras provenientes de desembarque em Macapá, Bragança e Fortaleza. As análises filogenéticas e populacionais revelaram que há apenas uma população panmítica e baixos níveis de variabilidade genética foram observados. Estes resultados, assim como a observada sobre-exploração de S. cavala, representam dados muito importantes para o estabelecimento do manejo deste estoque a fim de prevenir um colapso ou risco de extinção no futuro.

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ABSTRACT: Carcharhinus limbatus has a cosmopolitan distribution and marked genetic structuring, mainly because of its philopatric behavior. However, analysis of this structuring has not previously included South American populations. In the present study, we analyzed a sample of adult individuals collected on the northern coast of Brazil and compared the sequences of the mitochondrial control region with those of populations already genotyped. Relatively high haplotype diversity (12 haplotypes, genetic diversity of 0.796) was observed, similar to that in other populations but with a much larger number of private alleles. In contrast to populations studied previously, which were represented by neonates, the pronounced allelic variability found in the South American individuals may have resulted from migrations from other populations in the region that have yet to be genotyped. This population was also genetically distinct from the other Atlantic populations (Fst > 0.8), probably because of female philopatry, and apparently separated from the northwestern Atlantic group 1.39 million years ago. These findings indicate that the C. limbatus population from northern Brazil is genetically distinct from all other populations and should be considered as a different management unit for the protection of stocks.

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The evaluation of population characteristics, particularly those of endemic species, aids in population preservation and management. Hermit crabs present an innate behavior of occupying shells, which tends to individual needs and limits their distribution. This study characterized the pattern of occupation of gastropod shells by the hermit Loxopagurus loxochelis in three bays of the southwestern coast of Brazil. Monthly collections were made from January/1998 to December/1999 in the bays Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV) with a shrimping boat. Overall, ten species of gastropod shells were occupied by L. loxochelis. The shell of Olivancillaria urceus represented 66.8% of those occupied. Morphometric relationships demonstrated a differential occupation of the more abundant shells among demographic groups, where most of the males occupied O. urceus, non-ovigerous females occupied O. urceus and Buccinanops cochlidium, and ovigerous females occupied B. cochlidium and Stramonita haemastoma. Most of the individuals occupied the more abundant shells, considered adequate for the morphology of this hermit crab species. Thus, the studied bays seem to be stable and propitious environments for population perpetuation and the settlement of new individuals.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The species of the genus Pennella are highly modified copepods that have been found parasitizing several species of fishes in Atlantic waters. Although these parasites have been recorded several times in the Atlantic Ocean, little is known about them in South Atlantic waters, except for one report published 20 years ago. The present contribution reports the occurrence of Pennella instructa Wilson, 1917 parasitizing the swordfish Xiphias gladius Linnaeus, 1758 in the South Atlantic. The prevalence of infestation was 15.6% and the mean intensity of infestation was 1.6, ranging from 1 to 3.

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

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

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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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