We studied inter-and postnesting movements in the major loggerhead Caretta caretta nesting population in Brazil. Ten breeding females were satellite-tracked from nesting grounds in the state of Bahia, northeastern Brazil, for up to 1284 d. Eight females stayed in the nesting area after deployment, showing fidelity between internesting home ranges and nesting locations, even at a local scale. During postnesting movements, all of the turtles migrated to the northern coast of Brazil to individual foraging areas on the continental shelf. Distances between nesting and foraging areas reached up to 2400 km, and migration lasted from 28 to 47 d. Five females were tracked during subsequent breeding migrations to the nesting area at different remigration intervals of 2 or 3 yr. Females were also tracked during a second postnesting migration back to foraging areas, and these showed strong fidelity to foraging grounds. Movements to and from foraging grounds occurred along the shelf, clearly delineating a migratory corridor. The northern coast of Brazil, specifically the coast of the state of Ceará, is an important foraging ground for loggerheads nesting along the northern coast of Bahia.
Four female leatherback sea turtles Dermochelys coriacea were satellite tracked from the southeastern coast of Brazil (3 from nesting beaches in the state of Espírito Santo, and 1 recovered from a driftnet off the coast of the state of São Paulo), representing the first study of movements of leatherbacks nesting on Brazilian grounds. The results suggest that during the internesting period, leatherbacks may disperse up to 160 km from the nesting beach using an area of 4400 km 2. Tracking also revealed shared feeding areas in southern South America, comprising Brazilian, Uruguayan, and Argentinean waters, and highlighted important interactions with fisheries along nesting, migratory, and feeding habitats. The presence in migratory/foraging areas of turtles from at least 2 different nesting populations from both sides of the South Atlantic Ocean supports the concept that management efforts for this species must incorporate a broad regional perspective.
The worldwide population of the leatherback turtle (Dermochelys coriacea) encompasses seven subpopulations among the Pacific, Atlantic and Indian Oceans. It has experienced declines across parts of its distribution, with the subpopulation of the South-west Atlantic listed as critically endangered by the IUCN Red List. The main threats to this subpopulation include its interaction with fisheries, coastal development, pollution and climate change. In this study, we sequenced mitochondrial DNA from 52 leatherback turtles in Brazil and combined these with published data from other Atlantic Ocean rookeries. The haplotype diversities of the Atlantic population rookeries ranged from 0.112 to 0.533 and are not directly proportional to current rookery sizes. The Brazilian rookery, despite recording low nest numbers per year, had the second-highest haplotype diversity among all Atlantic rookeries (h = 0.532). A mixed-stock analysis revealed that the South American pelagic aggregate is primarily composed of individuals from West Africa (84%), with contributions from the North Atlantic rookeries (14%). Leatherback turtles appear to have a complex phylogeographic pattern, showing evidence of multiple colonization events and a lack of isolation by distance. Our novel dataset, based on DNA sequences of 695 base pairs, will provide baseline data needed to understand population dynamics in the region, building comprehensive population assessments to support and develop management strategies. Having both the only known regular rookery in the South-west Atlantic, and a mixed-origin foraging area for the species along its coast, Brazil has a key role in the conservation of the leatherback turtle.
In the southwestern Atlantic Ocean, leatherback turtles Dermochelys coriacea are only known to regularly nest in eastern Brazil, on the coast of the state of Espírito Santo. Here, we present an analysis of the nesting ecology, population trends and conservation status of this leatherback turtle colony between 1988 and 2017. We observed an increasing, although variable, trend in the annual number of nests, with the mean increasing from 25.6 nests in the first 5 yr of the study to 89.8 in the last 5 yr. Concurrently, there was also a significant decrease in the mean curved carapace length of the population, which we hypothesize was caused by recruitment of new females to the nesting population. Throughout the study period, nests were concentrated in the southern part of the 160 km long study area. No change was observed in the annual median nesting date. Mean annual hatching success was 66.0% and no significant variation in hatching success was detected after a major spill of mining tailings into the nesting area in 2015. We postulate that local conservation actions that started in the 1980s have contributed to the gentle recovery of this population; however, given the small population size and restricted nesting geographical distribution alongside the persistence of various threats-fisheries bycatch, climate change, pollution and coastal development-this population continues to be of conservation concern.
In the 35 years since its inception, the Brazilian National Program for the Conservation of Marine Turtles (TAMAR) has had great success in protecting the five species of sea turtles that occur in Brazil. It has also contributed significantly to worldwide scientific data and knowledge about these species' biology, such as life cycles and migration patterns. TAMAR's conservation strategies have always relied on a variety of environmental education and social inclusion (EESI) activities highly adapted to the socioenvironmental evolving contexts of its 25 locations distributed across nine states. Diversity and flexibility are critical to enable timely and effective local responses to existing or potential threats to sea turtles. The intuitive, locally adapted, decentralized, and independent way EESI activities have been carried out have generated positive results in the resolution of specific and evolving local problems through the course of the project. This article brings EESI under the same conceptual framework that underlies its conservation approach by adopting an adaptive threat management framework to organize and qualify its educational and social inclusion interventions according to the main categories of threat addressed by TAMAR.
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