203 resultados para Sloanea guianensis
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Four areas are known as of frequent usage by Guiana dolphins (Sotalia guianensis) in the south coast of Rio Grande do Norte state, northeast Brazil: Tabatinga, Pipa, Lagoa de Guaraíras and Baia Formosa. This extension of 40 km of shoreline is under increasing anthropogenic impacts due to continuous development of the coastal areas and vessel traffic. The objective of this study was to investigate aspects of population biology and habitat use of the population of Sotalia guianensis in the south coast of Rio Grande do Norte. It was applied the photo-identification technique and posterior methods of capture-recapture for population estimation (POPAN extension in MARK). The distribution, movement and site fidelity of the dolphins were analyzed trough the geographic information system (GIS) and group characteristics and behavior trough non-parametric statistics. Field work was conducted on board a 10m motor vessel from March 2008 to March 2009. Photo-identification effort was 329h with 113h of direct observation of the dolphins. The population estimatives for each area: Tabatinga: 75 (63-92); Pipa 105 (88-129); Lagoa de Guaraíras: 27 (18-54) e Baia Formosa: 112 (89-129) individuals. Total population estimative was: 223 (192 a 297). High site fidelity was detected for only part of the population (<15%) as low site fidelity and transients individuals were also detected (>20%). It was observed frequent movements between Tabatinga, Lagoa de Guaraíras and Pipa, but not Baía Formosa. This suggests a division in two communities along this shore extension: one in Pipa and other in Baía Formosa. Group size was small, most groups with up to 10 dolphins. The areas were use intensively, only in Lagoa de Guaraíras dolphins were not seen in all field trips. Lagoa de Guaraíras is an area used by small groups exclusively for foraging. In Tabatinga and Pipa dolphins concentrated close to the shore, in the inner sector of the area and the main activity is also foraging. Significant larger groups were seen in socializing behavior but there was no difference in group size between the inner and external sectors of the area. The presence of calves and juveniles were significant greater in the inner areas of Tabatinga and Pipa, confirming the hypothesis that these beaches are also used for parental care. In Baia Formosa dolphins concentrated in the outer sector and foraging was also predominant. Significant larger groups were seen in the outer sector, mainly engaged in mixed behaviors of travel/foraging, possibly in some kind of group foraging. Calves and juveniles were significant more present in the outer sector where group size was also larger. In general there was no difference in area usage and period of the day. Sotalia guianensis has characteristics that make the species vulnerable to human activities such as small population concentrated in patches of suitable habitats restrict to coastal areas. We hope that this study bring new information for the species and help for the adequate management of the area in order to assure the presence of the dolphins as well as its behavior pattern and gene flow betweencommunities.
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Social behavior of Guiana dolphins, Sotalia guianensis, at Pipa Beach, RN, Brazil: dynamics, sequence, breathing synchrony, and responses to dolphin watching. Social animals form groups that can range from temporary to permanent. Depending on the nature of the social relationships developed between individuals, groups present a particular social organization and the effect of these interactions shapes the activity patterns of these animals. This study investigates: (i) fission-fusion dynamics of Guiana dolphins, through the analysis of three dimensions of the social system (variation in spatial cohesion, variation in size and composition of groups), (ii) sequence, routine and behavioral stability, (iii) breathing intervals in synchronized groups and (iv) behavioral responses of the animals to dolphin watching. Systematic observations of Guiana dolphins were made from a platform located in cliffs about 25 m above sea level that surround Madeiro Bay, Pipa Beach. Sampling occurred from December 2007 to February 2009 between 0600 h and 1600 h, and the groups of Guiana dolphins were investigated according to their size (alone and group) and composition (adults, adults and juveniles, and adults and calves). According to the analysis of fission-fusion dynamics, Guiana dolphin groups frequently changed their composition, modifying their patterns of spatial grouping and cohesion every 20 minutes on average. More than 50% of the individuals maintained a distance of up to 2 m from other group members and new individuals were attracted to the group, especially during feeding, leaving it for foraging. Large groups were more unstable than small, while groups containing only adults were more stable than groups of adults and juveniles. According to the Z-score analysis to investigate the sequence and behavioral routine, lone individuals were more ! .7! ! involved in foraging and feeding, while resting was more common in groups. Foraging and feeding were more common in homogeneous groups (individuals of the same age class), while heterogeneous groups (different age classes) were often involved in socialization, displaying a broader behavioral repertoire. Foraging and resting behavior presented higher stability (continuous duration in minutes) than the other behaviors. The analysis of breathing intervals in synchronized groups showed significant differences depending on type of behavior, composition and area preference. During resting, breathing intervals were of longer duration, and groups with calves showed shorter breathing intervals than groups without calves. Lone individuals also preferred areas called corral , often used for the entrapment of fishes. The Markov chain analysis revealed behavioral changes in the presence of boats, according to the type of group composition. Groups composed of adults presented decreased resting and increased in traveling during the presence of boats. Groups of adults and juveniles showed a massive reduction of socialization, while the behavior transition probability traveling-traveling was higher in groups of adults and calves. In the presence of the boats, stability of resting was reduced by one third of its original duration and traveling more than doubled. The behavioral patterns analyzed are discussed in light of socio-ecological models concerning costs and benefits of proximity between individuals and behavioral optimization. Furthermore, significant changes in behavioral patterns indicate that Guiana dolphins, at Pipa Beach, have suffered the effects of tourism as a result of violation of rules of conduct established for the study area
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To clarify the functional mechanisms of habitat use is necessary to analyze it in conjunction with the conduct performed by animals. The occurrence, distribution and use of space are characteristic of a species resulting from habitat selection that is in search of conditions favorable to its survival. One can relate the physical and biological factors of the environment with the ecological characteristics of the species, since these factors act by regulating the ecological success of organisms, and from there you can get important information about the habitat use and behavior of individuals. This study aimed to characterize the use of habitat and diurnal activity expressed by the Guiana dolphin, Sotalia guianensis in an estuarine area of Sergipe state, Brazil, analyzing the influence of tide and time days on the occurrence of animals and behavior s state, and group s size and composition in this cetacean species. From March 2009 to February 2010, focal groups observations of dolphins were made from fixed - point and records snapshots of data taken every 5 min. in the interval from 6 a.m to 6 p.m, in alternating shifts. The results showed that the constant presence of animals in the area of the Sergipe River estuary indicates that this is an important area of occurrence of S. guianensis, which use the region mainly in the morning, at low tide and as a feeding. As in other regions of northeastern Brazil, small groups formed 2-12 individuals were most common, with adults and immatures. The high frequency of immature animals may indicate that this area of the estuary is used as brood area and parental care of pups and young animals, since the immature animals were very associated with adults and monitoring the activities of foraging / feeding may be related to a form of learning or training of such behavior
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A fundamental analysis on Behavioral Ecology is the construction of Activities Budget, which can be defined as the quantification of the time that each animal uses in activities that are important for its survival and reproduction. Initially developed for theoretical studies about Optimal Foraging, the construction of Activities Budgets has recently being used for analyses in Conservation Biology. However, the measurement of behavior through an adequate methodology that allows the comparison between different samples is a challenge for researchers in the area of Ethology. This problem is even bigger for the students of cetaceans behavior due to the difficulty of visualization of these animals. The present work deals with two aspects of the specialized literature on cetaceans: i) it explores possible variations of results in quantification of behavioral states decurrent of the application of different methods of data collection, and ii) it describes the activity budget of a population of Sotalia guianensis that inhabits coastal waters, south Rio Grande do Norte. The results showed that the use different methods of data collection result in significant differences, but of small scale, in the quantification of the behavioral frequency. The activity budget of Sotalia in the area here analyzed was similar to that described for other populations of this species inhabiting typically estuarine habitats. Tide and day-hour did not influence the dolphin s behavior, however, significant differences were found related to the position of the animals within the area. These results are discussed considering the dietary and behavioral flexibility of the species, contributing to the scientific knowledge and offering information that will be useful in comparative studies and for analyses on the determination of areas for species conservation
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The aim of this study was to investigate the daily and annual variation in frequency and in activity of an estuarine dolphin population, Sotalia guianensis, in Brazilian northeastern. Thus we estimated the daily variation and seasonality in frequency of adult and immature and in behavior of socialization, aerial activity, foraging of a boto equatorial population in the Curral inlet (6º13 00 S; 35º3 36 W). We detect some variation. Thus we associate the daily variation with daily period, tide fluctuation and annual season. And the seasonality variation we associate with the fotoperíodo and precipitation variation. From October 1999 to September 2003, through collect four times at month, we made instantaneous record at each five minute in six hours of survey. The surveys hours were ranged into light time of 24 hours, that is, between 06:00 and 17:00 o clock. These observations were developed simultaneous for two observers in a land-based survey at coastline cliff top of which observer have a fully visualization of whole inlet. We found that animals were more active and frequent during the morning. They were more active during low tide than high tide. However they did not show association with tide. We found yet that in a period from June to November (winter-spring) there was the highest socialization, aerial activity and foraging frequency. However adult and immature individual number did not have significance variation along the year. The larger concentration of this behaviors were not associate with photoperiod neither precipitation in the region. These results showed the existence of behavioral daily variation and seasonality in a species that live in equatorial region
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The marine tucuxi, Sotalia guianensis, is one of the smallest known cetaceans, has coastal habits, and occurs from Hondures to Santa Catarina, in southern Brazil. The objective of this dissertation was to describe diving behavior of the marine tucuxi in three age classes and to analyze the cardiac capacity to dive through the examination of hearts of stranded specimens. Observations were made from October 2004 to November 2005 from a vantage point, in Curral Bay at Pipa beach-RN. We used Ad Libitum sampling and All occurrences to record the behaviors. The diving was characterized by the total exposition of the tail fluke for a few seconds, in 90° or 45° angles. Were recorded 131 dives in three behavioral contexts: foraging, traveling and socialization. The difference between juveniles and adults in dive time and fluke out at 45° or 90° to search and/or capture prey is probably influenced by the strategy used and ability to capture the prey. The frequency of fluke out at 90° for foraging in adults may be related to increased physiological efficiency of adults in comparison to juveniles. However, in the context of travel and socialization the dive time and fluke out were independent between the age classes. Dive in calves were frequent during socialization (play behavior) and traveling. This, associated with synchronic calve-adult diving suggests that a relationship of these behaviors and the acquisition of experience and foraging skills. As observed in other cetaceans, the heart (n=12) of the estuarine dolphin is broad and presents long ventricles which form a round apex. The right ventricle is long and narrow. The degree of dilatation of the aortic bulb may support the heart during diastole. The characteristic morphology of the heart and short dive duration < 2 min and depth ranged from 10m in the estuarine dolphin, can be likely at physiological adaptation for diving, typical de dolphins with coastal habits. The limitation of diving time in this specie may be influenced by anatomical and physiological restrictions
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In some species parental care is vital to survival. Many studies have reported various parental care behaviours in cetaceans. In Sotalia guianensis, some behaviours have been already described and linked to parental care. However, many aspects are still unknown and all these information might be important for the species conservation. The aim of the present study was minimize these gaps, showing the options involved in the marine tucuxi parental care. The observations took place in Enseada do Curral, located in Pipa, Tibal do Sul, Rio Grande do Norte Coast. Between January and December of 2005 the local population of tucuxi was observed during 42 days. The methods used were Focal Animal and Ad Libitum. The results suggest that calves are present in the bay all year long. Groups with calves had a mean of 6,9 animals, allowing the animals to participate in different activities in the group besides caring. The calves created different associations, being usually followed by an adult. In groups, the calves stay mainly in the centre, which offers them protection. Calves remained next to the adults tail, facilitating breastfeeding. The calves most noticeable activities were those in the surface and the behaviour frequencies decreased, in general, in the presence of human swimmers and boats, what could be considered a threat to the animals. Adults shared positions when caring for calves, suggesting allomaternal care; food transfer from adults to calves was observed, which might be related to diet acquisition; three non-described behaviours were seen, indicating a diversified behavioural repertoire for this species
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The behavioral patterns follow to environmental changes, including area fidelity and individuals association patterns. Several techniques are used to record these behavioral patterns and the photo-identification has been suggested as a proper tool because of its various advantages. Based on this technique, this research verified, between August of 2005 and January of 2006, area fidelity and association patterns of Sotalia guianensis, at Distrito de Pipa s bays, Rio Grande do Norte State south coast. Besides, we measured the association patterns by using the Jaccard index or Half-Weight Index (HWI). According the observation, 22 individuals were not resighted, 11 were resighted, and 36 new individuals were recorded. Nowadays, 69 individuals are cataloged. The residency rate indicated heterogeneity on studied area permanence and the association patterns between photo-identified seem to be context-specific. In addiction, the comparison of associations between two different age classes showed some individuals more frequently interacting with immature individuals. We also observed fluidity on association patterns among our individuals. We suggest that S. guianensis population from Pipa shows plasticity
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Synchronism is the efetivation of the same behavior at the same time by two or more individuals. In cetology only from 2000 we verify an increasing of efforts for studies of synchronic behaviors. The synchronism in cetaceans was reported for a variety of contexts, including feeding, socializing, parental care, while resting, traveling and play, during afilliation, in sexual behaviour and possible while teaching. The synchronism in behavior is influenced by environmental factors and can be modified during stress situations such as the presence of boats. The aim of this study is to explore behavior synchronism presented by the estuarine dolphin (Sotalia guianensis) in Pipa, Rio Grande do Norte state, Northeastern Brazil. A total of 414 hours of observation during the year 2006, using scan sampling method, from a land based sighting was conducted. Analyses were conducted in four steps. Firstly, we determined the pattern of activity of the groups within the bay, testing for the influence of bay configuration before and after rains periods on the activity of animals. Analyses show that forage occurs more frequently after the rainy period, but there was no change in the number of individuals or spatial cohesions between them. Secondly, we analysed the influence of turism boat traffic on the behavior of animals. We verified no changes on the bahavior of animals during the presence of boats. Finally, we tested seven hypotheses regarding the ecological and social dynamics of synchronic behavior. Environmental aspects were considered the main influence for the synchronism, no influences of age, and more selective exihibition of synchronic breathing in feeding and social displays were observed during the study period
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O DEET (N, N-dietil-3-metilbenzamida) é hoje o repelente mais efetivo disponível, porém, seu uso pode apresentar importantes efeitos colaterais tópicos e sistêmicos. Alguns compostos botânicos, como a Andiroba (Carapa guianensis), têm demonstrado propriedades repelentes a um baixo custo e baixa toxicidade. Quatro voluntários hígidos submeteram seus antebraços recobertos com óleo de Andiroba a 100%, DEET 50% (controle positivo), óleo de soja refinado, óleo de Andiroba 15% e na ausência de produtos (controles negativos), diretamente a picadas de fêmeas saudáveis de Aedes sp. Foram aferidos os tempos da primeira e terceira picadas. Os resultados mostraram que a mediana da primeira picada nos antebraços sem produto foi 17.5s e a terceira picada, 40.0s. No óleo de soja, as picadas ocorreram em 60.0s e 101.5s. No óleo de Andiroba 100%, em 56.0s e 142.5s. Com Andiroba 15%, em 63.0s e 97.5s. Usando DEET 50% não houve picadas após 3600s na maioria dos experimentos (p < 0.001 Wilcoxon). O óleo de Andiroba 100% comparado ao óleo de soja, antebraço sem produto e óleo de Andiroba 15%, mostrou discreta superioridade (p < 0.001 Wilcoxon). Concluímos que o óleo puro de Andiroba apresenta efeito repelente discreto contra picada de Aedes sp., sendo significativamente inferior ao DEET 50%.
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Even though shark-cetacean interactions have been the subject of numerous studies worldwide, several ecological aspects such as competition, predation risk and co-evolution remain unclear. on February 16th, 2008, during a photo-identification survey to investigate population parameters of Guiana dolphins, Sotalia guianensis, in estuarine waters of Parana State (25[degree]S; 48[degree]W), Brazil, an adult dolphin was photographed without its dorsal fin. A detailed analysis of the healed area on the injured dolphin showed that the circular, crescent-shaped outlined wound was provoked by the bite of a bull shark, Carcharhinus leucas. Wound shape, prey-predator distributional patterns (sympatry) and feeding habits of the shark species here considered were indicative of the species' identity. The wound is likely to be the result of a failed predation attempt. Interactions between C. leucas and S. guianensis should be expected, since they are sympatric along almost all of their distribution range in the tropical and subtropical western South Atlantic. The presented observation adds S. guianensis to the list of cetacean species involved in interactions with large coastal predatory sharks.
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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)