34 resultados para Chiloé Archipelago
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
Resumo:
A series of quali- and quantitative analyses were conducted to evaluate the variability of spinner dolphin whistles from the Fernando de Noronha Archipelago off Brazil. Nine variables were extracted from each whistle contour, and the whistle contours shapes were classified into the seven categories described in Driscoll (1995). The analysis showed mean beginning and ending frequencies values of 10.78 and 12.74 kHz, respectively. on average, whistle duration was relatively short, with mean values around 0.495 s (N=702). Comparative analyses were also conducted to investigate the relationship between the obtained results and those presented in previous studies. When comparing averages, the results of the study of Oswald et al. (2003) in the Tropical Eastern Pacific (TEP) presented less significant differences in relation to this study; only whistle duration differed significantly between both works. The results of multivariate classification tests also pointed TEP population as the closest related to the population studied here. The similarities between such disjunct populations might be attributed to a more recent isolation event (the closing of the Panama Isthmus) than the divergence that has driven North and South Atlantic populations apart. (c) 2006 Acoustical Society of America.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Parrotfishes are important components of the herbivore and detritivore guilds of tropical and subtropical reefs. Most of parrotfish species are protogynous hermaphrodites that change colour and sex, from initial phase females or males (IP) to terminal phase males (TP). We studied the foraging behaviour of Sparisoma amplum, S. axillare and S. frondosum, three syntopic scarids on the rocky reefs of Fernando de Noronha Archipelago, Tropical West Atlantic. The three parrotfish species differed in food selection and preference, but IP and TP individuals of the same species preferred the same food types, except for S. amplum. Feeding rates of IP individuals were higher than those of TP individuals, but the distribution of feeding frequencies throughout the day of IP and TP individuals of the same species was similar. IP individuals had higher feeding rates than TP ones, which seems related to the fact that TP individuals spend a large amount of time patrolling their territories and chasing away conspecific individuals at the study site. The general foraging pattern we found for S. amplum, S. axillare and S. frondosum is similar to patterns found for other parrotfish species in the Western Atlantic.
Resumo:
Habitat of juvenile Caribbean reef sharks, Carcharhinus perezi (Carcharhinidae), was identified using fishing surveys and capture of immature specimens at two Brazilian insular sites in the southwestern Atlantic Ocean, Fernando de Noronha Archipelago and Atol das Rocas. Standardized sampling at Fernando de Noronha indicated that parturition occurred from February to April and that a wide depth-range (at least 5-30 m) along the insular shelf was used by immature sharks throughout the year. The catch-per-unit effort of C. perezi was significantly higher inside than outside a marine protected area at this location, suggesting that these sharks are more common in pans of the reef least disturbed by human activities. More limited sampling at Atol das Rocas suggested that juvenile C. perezi occurred at similar depths and utilized similar substrate as sharks at Fernando de Noronha. These findings suggest that successful conservation and management of this economically important, protected species will need to include conservation of habitat around insular reef systems. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
In March 1993, a specimen of Carcharhinus leucas was captured by fishermen on the south coast of Terceira Island, the Azores Archipelago. Its head was recovered and its jaws were preserved. This is the first capture of this species on an oceanic insular shelf in the Atlantic. The distribution of C. leucas in this ocean is commented.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Biodiversity can be useful as an ecosystem indicator for conservation and monitoring, through continuous assessment of its main properties including stability, primary productivity, exploitation tolerance and even global environmental changes. The main purpose of this study was to provide a checklist of the crabs associated with subtidal rocky bottoms at the Vitoria Archipelago, southeastern Brazilian coast. Monthly collections were carried out from February 2004 through January 2006 on three islands at the Vitoria Archipelago (23[degree]44'S-45[degree]01'W). The crabs were hand-caught by SCUBA divers during the daytime, in rock subtidal. A total of 3084 individuals were caught, belonging to 42 species, 28 genera, and 12 families, highlighting Mithraculus forceps (1528) and Stenorhynchus seticornis (407) representing more than 60% of the sample. on the other hand, Dromia erythropus, Moreiradromia antilensis, Ebalia stimpsoni, Garthiope spinipes and Tumidotheres maculatus had only one individual sampled.
Resumo:
To properly describe the interactions between the ocean and atmosphere, it is necessary to assess a variety of time and spatial scales phenomena. Here, high resolution oceanographic and meteorological data collected during an observational campaign carried out aboard a ship in the tropical Atlantic Ocean, on May 15-24, 2002, is used to describe the radiation balance at the ocean interface. Data collected by two PIRATA buoys, along the equator at 23°W and 35°W and satellite and climate data are compared with the data obtained during the observational campaign. Comparison indicates remarkable similarity for daily and hourly values of radiation fluxes components as consequence of the temporal and spatial consistence presented by the air and water temperatures measured in situ and estimated from large scale information. The discrepancy, mainly in the Sao Pedro and Sao Paulo Archipelago area, seems to be associated to the local upwelling of cold water, which is not detected in all other estimates investigated here. More in situ data are necessary to clarify whether this upwelling flow has a larger scale effect and what are the meteorological and oceanographic implications of the local upwelling area on the tropical waters at the Brazilian coast.
Resumo:
Two defensive tactics of neonates of nurse sharks, Ginglymostoma cirratum, are reported based on underwater observations. Described as "hiding behaviour" and "substrate resemblance", the defensive strategies were categorized according to the predominant habitat in which the individuals were found and to the behaviour displayed by the sharks in the presence of the observer. In structurally more complex habitats with a wide availability of shelters, the preferential behaviour displayed by neonates is to hide inside holes or crevices. When in open areas deprived of refuges, neonates tend to resemble arborescent coverings as seaweed banks or colonies of octocorals, which allows the use of more exposed habitats without increasing the susceptibility of capture by predators. Both aspects are relevant for a better understanding of the behaviour of neonates of G. cirratum and have important implications for identifying important habitat in nursery areas, and also for the management of this vulnerable species off South America.
Resumo:
The Asian subterranean termite, Coptotermes gestroi, originally from northeast India through Burma, Thailand, Malaysia, and the Indonesian archipelago, is a major termite pest introduced in several countries around the world, including Brazil. We sequenced the mitochondrial COII gene from individuals representing 23 populations. Phylogenetic analysis of COII gene sequences from this and other studies resulted in two main groups: (1) populations of Cleveland (USA) and four populations of Malaysia and (2) populations of Brazil, four populations of Malaysia, and one population from each of Thailand, Puerto Rico, and Key West (USA). Three new localities are reported here, considerably enlarging the distribution of C. gestroi in Brazil: Campo Grande (state of Mato Grosso do Sul), Itajai (state of Santa Catarina), and Porto Alegre (state of Rio Grande do Sul).
Resumo:
Mammals has been pointed out to be the main nest predators in islands, but recent studies has shown that tree snakes are also important nest predator in tropical forests. Here we present information on the density tegu lizards Tupinambis merianae and its role as nest predator at Anchieta Island, Ubatuba, in southeastern Brazil. The mean density of tegu lizards wets estimated to be 83 individuals/km2, which is 1.83 times lower than other well-known population (Fernando de Noronha Archipelago). In the dense rainforest, the density was estimated in 20 individuas/ km2, and in the open rainforest, 109 ind/km2. The high density of this lizard may have serious implications for nest predation. We found that 36% of artificial plasticine eggs were "preyed upon" by tegu lizards. Therefore, it is paramount to manage the tegu population on Anchieta Island to assure the survival of ground nesting birds in islands and possibly in forest fragments.
Resumo:
The influence of a substratum-disturbing forager, the spotted goatfish Pseudupeneus maculatus on the assemblage of its escorting, opportunistic-feeding fishes was examined at Fernando de Noronha Archipelago (tropical west Atlantic). Followers attracted to spotted goatfish foraging singly differed from followers of spotted goatfish foraging in groups in several characteristics. The larger the nuclear fish group, the greater the species richness and number of individuals of followers. Moreover, groups of foraging spotted goatfish attracted herbivores, not recorded for spotted goatfish foraging singly. The size of follower individuals increased with the size and the number of foraging spotted goatfish. The zoobenthivorous habits of the spotted goatfish and its ability to disturb a variety of soft substrata render it an important nuclear fish for several follower species of the reef fish assemblage at Fernando de Noronha. (c) 2006 the Authors Journal compilation (c) 2006 the Fisheries Society of the British Isles.