Navegando por Assunto "Satellite tracking"

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Artigo
Olive ridley inter-nesting and post-nesting movements along the Brazilian coast and Atlantic Ocean. Endangered Species Research
(2019-11-14) SANTOS, E.A.P.; SILVA, A.C.C.D.; SFORZA, R.; OLIVEIRA, F.L.C.; WEBER, M.I.; CASTILHOS, J.C.; LÓPEZ-MENDILAHARSU, M.; MARCOVALDI, M.A.A.G.; RAMOS, R.M.A.; DIMATTEO, A.
The states of Sergipe and Bahia comprise the main nesting beaches for olive ridley sea turtles Lepidochelys olivacea in Brazil. Between February 2014 and March 2015, 40 L. olivacea were equipped with Argos platform transmitter terminal tags. A state-space model was applied to Argos location data to investigate the animals’ spatial ecology and identify areas of restricted movements (ARMs) and directional movements. The inter-nesting ARMs included the continental shelf from the south of Alagoas state to the north of Bahia, totaling 7244 km2 (kernel density estimation, 90% isopleth) and generally extended up to 22 km from the coast or to the 50 m isobath. The post-nesting directional movements were classified as either (1) neritic north/ northeastern (N/NE) Brazil to French Guiana (n = 4 turtles), (2) neritic south/southeastern (S/SE) Brazil (n = 16), or (3) oceanic (n = 19) from Brazil to West Africa. ARMs consistent with foraging areas were identified for 24 olive ridleys: 15 along the continental shelf of SE Brazil, 2 adjacent to Ceará and Maranhão states (between the 25 and 75 m isobaths), and 7 off the African countries of Cape Verde, Senegal, Gambia, Guinea-Bissau, and Sierra Leone. The results de monstrated the complexity of olive ridley movements from northern Brazil, raised questions about connectivity, and highlighted threats such as fisheries, ports, and hydrocarbon exploration fields overlapping with, or near to, high-use areas. These results can be used as a basis for spatial management measures to protect this endangered species.
Artigo
Satellite-tracking Reveals Multiple Foraging Strategies and Threats for Olive ridley Turtles in Brazil
(2011-12-20) SILVA, A. C. C. D.; dos SANTOS, E. A. P.; OLIVEIRA, F. L. C.; WEBER, M. I.; BATISTA, J. A. F.; SERAFINI, T. Z.; CASTILHOS, J. C.
The state of Sergipe in northeastern Brazil is the largest nesting area for olive ridley turtles along this nation’s coast, and constitutes a major rookery in the western Atlantic as well. Conservation efforts with a focus on nesting activities have been implemented there since 1982, but little is known about other aspects of the life cycle, specifically post-nesting movements of females and the locations of foraging grounds. To address this issue, satellite transmitters were deployed on 10 females that nested between February and April 2006. The turtles were monitored for an average of 113 d (range: 14 to 297 d), and an average movement of 1669 km (range: 407 to 4265 km) was recorded. Of the 10 turtles monitored, 6 moved along the Brazilian continental shelf to neritic foraging areas. Five of these turtles utilized foraging areas along the northern and northeastern coasts of Brazil, while one foraged along the southeastern coastline. Two females were tracked to equatorial oceanic waters, with one first moving to an inshore foraging site where she remained for 34 d before migrating to oceanic waters off the Brazilian coast. Signal transmission of 3 of the 10 turtles tracked ceased during their post-nesting migrations, preventing identification of their feeding areas. Olive ridley turtles nesting on the coast of Sergipe displayed a range of post-nesting movements including to coastal sites along the continental shelf as well as offshore oceanic areas. Inter-nesting habitats, migration routes and foraging grounds showed great overlap with a variety of coastal fisheries, as well as with longline fishing in oceanic waters, a key consideration for developing conservation strategies for this species in the western Atlantic.
Artigo
Sattelite-tracking of female loggerhead turtles highlights fidelity behavior in northeastern Brazil
(2010-08-11) Marcovaldi, Maria Ângela; Lopez, Gustave G.; Soares, Luciano S.; Lima, Eduardo H. S. M.; Thomé, João C. A.; Almeida, Antonio P.
ABSTRACT: 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.