Papers by Leonardo Wedekin
Marine Mammal Science
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Journal of Mammalogy
Ecological niche models (ENMs) predict where species can occur in accordance with environmental f... more Ecological niche models (ENMs) predict where species can occur in accordance with environmental factors. Suitability maps are generated through models to identify habitats more or less adapted to the species. Published works on the distribution and habitat use of Guiana dolphin, Sotalia guianensis, are limited to fine spatial scales. Here, we aimed to predict the potential geographical distribution of Guiana dolphins through ENMs and generate a map of suitable habitats for the species. Data were collected between 1997 and 2015 in Brazil, French Guiana, and Colombia. The environmental data were obtained from MARSPEC database with a cell resolution of 10 × 10 km. For modeling, 99 of the 859 initial occurrence points of the species were considered after rarefaction. Seven environmental variables were selected through factorial analysis: bathymetry, distance to shore, bathymetric slope, sea surface salinity (minimum monthly and annual range), and sea surface temperature (mean annual and...
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Marine Mammal Science
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Population Ecology
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Ecological Modelling
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Brazilian journal of biology = Revista brasleira de biologia, 2007
The use of space by the resident population of estuarine dolphins (Sotalia guianensis) in Norte B... more The use of space by the resident population of estuarine dolphins (Sotalia guianensis) in Norte Bay, southern Brazil was studied by boat surveys between 2000 and 2003. Data such as the geographical position and group size was collected at 5-minute intervals using focal-group sampling. The distribution and seasonal and daily group home-ranges were estimated using a GIS (Geographic Information System) environment. The dolphins did not use the area homogeneously, restricting their activities to a well-defined area located in the western part of the bay, while the use of the eastern part was not observed. A discrepancy between the Environment Protection Area of Anhatomirim, created especially to protect this population and the distribution of the dolphins was observed. Seasonal group home-range varied both qualitatively and quantitatively among the four consecutive seasons analyzed. The dolphins tended to use a larger area in cold seasons, when apparently the abundance of major prey ite...
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Latin American Journal of Aquatic Mammals, 2010
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The Environmental Protection Area of Anhatomirim, Santa Catarina State, was created mainly with t... more The Environmental Protection Area of Anhatomirim, Santa Catarina State, was created mainly with the objective of protecting a resident population o f the marine tucuxi, Sotalia gu ianensis. Using GIS, the present study compared the distribution o f this species and the design o f the EPA, aiming to v erify if this protected area meets its objective in respect
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Aquatic Conservation: Marine and Freshwater Ecosystems, 2014
ABSTRACT 1. Ship strikes are one of the major threats to large whales worldwide. The potential im... more ABSTRACT 1. Ship strikes are one of the major threats to large whales worldwide. The potential impact from increasing vessel traffic therefore is a concern for the future of the Brazilian humpback whale (Megaptera novaeangliae) population. 2. In order to evaluate the risk of collision between large vessels and humpback whales along coastal shipping routes in the region of the Abrolhos Bank – the most important breeding ground for the species in the south-western Atlantic Ocean – commercial vessels were used as platforms of opportunity to monitor the coastal shipping routes. 3. Humpback whale density along coastal routes was estimated through multiple covariate line-transect 'distance sampling'. The number of potential collisions per year was estimated using a model based on vessel size and speed, track lengths, population density and the surfacing behaviour of whales. 4. During the peak of the 2011 breeding season, whale density on the coastal route between Belmonte and Caravelas was estimated to be 0.085 whales km -2 and between Caravelas and Barra do Riacho, 0.023 whales
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Latin American Journal of Aquatic Mammals, 2006
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Biota Neotropica, 2008
Aiming to verify the movements of the bottlenose dolphin (Tursiops truncatus) at Rio de Janeiro S... more Aiming to verify the movements of the bottlenose dolphin (Tursiops truncatus) at Rio de Janeiro State coast, southeastern Brazil, we performed a photoidentification comparison between the catalogued individuals of the Cagarras Archipelago (23° 02' S and 43° 12' W) in 2004 and 2006 (n = 26) and the images obtained (n = 179) during the Southeastern Cetaceans Expedition, conducted during months of June and November of 2005. Eight individuals (three females and five dolphins of unknown gender) identified in the Cagarras Archipelago were resighted in the Grande Island (23° 21'S and 44° 15' W), about 100 km southwestwards from Cagarras Archipelago. The observed movements include distances commonly recorded for the species elsewhere and are probably related to search for prey.
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Marine Biodiversity Records, 2014
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Journal of the Marine Biological Association of the United Kingdom, 2012
Humpback whales (Megaptera novaeangliae) migrate between their feeding grounds, located in high l... more Humpback whales (Megaptera novaeangliae) migrate between their feeding grounds, located in high latitudes, and their breeding grounds, located in low latitudes, exhibiting certain levels of site fidelity to their migratory destinations. The residence time, also known as occupancy rate, can be defined as the minimum number of days that those individuals remained in the same area. In this paper, site fidelity and residence time of humpback whales that breed off the northern coast of Bahia, Brazil were investigated. Data were collected between 2000 and 2009 on-board research cruises and whale watching vessels. This paper also studies possible differences between males and females with respect to site fidelity off the Brazilian coast, using data collected since 1989. A total of 841 whales were photo-identified. The vast majority of the whales (96%, N = 809) were seen only once in the studied area, while 4% (32 individuals) were seen twice. Most of the resights occurred within the same s...
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Papers by Leonardo Wedekin