The Brazilian continental margin

Martins, Luiz Eduardo Galvão; Coutinho, P.N.

doi:10.1016/0012-8252(81)90007-6

Cited by 83 publications

(64 citation statements)

References 4 publications

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“…30-m while exhibiting transient behavior, similarly to that observed in an adult male C. leucas moving off the southeast coast of the United States (Carlson et al, 2010). The use of deeper isobaths while moving off the southeastern Brazilian coast could be explained by the considerably wider shelf (90,210 km) and deeper shelf break (150-185 m) in this region (Martins, Coutinho, 1981). The continuous use of inshore habitats by C. leucas throughout its lifecycle increases the species' exposure to potentially harmful impacts resulting from anthropic interference, which is obviously higher in these habitats (Beatley et al, 2002).…”

Section: Discussionsupporting

confidence: 66%

“…It seems thus unlikely that the shark had moved at superficial waters from the oceanic province for such a protracted period, as proposed by the location estimates of the UKFSST algorithm. Considering that C. leucas exhibit a clear preference for coastal habitats (Carlson et al, 2010;Hammerschlag et al, 2012;Heupel et al, 2015;Graham et al, 2016), the fact that the maximum depth registered by the transmitter (64 ± 4 m) matches the minimum depth of the continental shelf break (Martins, Coutinho, 1981) suggests that this shark moved mostly within the neritic province. Previous tracking studies on C. leucas across the oceanic realm reported movements through greater depths (122-164 m) and lower temperatures (16-21ºC) (Carlson et al, 2010;Lea et al, 2015) than the shark tracked in this study, which sustain such a hypothesis.…”

Section: Discussionmentioning

confidence: 91%

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Bioecology and movements of bull sharks, Carcharhinus leucas , caught in a long-term longline survey off northeastern Brazil

2017

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Bioecology and movements of bull sharks, Carcharhinus leucas, caught in a long-term longline survey off northeastern BrazilYuri V. Niella 1, 2 , André S. Afonso 2 and Fábio H. V. Hazin 2 A robust understanding of habitat usage by coastal shark species, and how it overlaps with human presence in denselypopulated regions is needed to inform the development of efficient conservation strategies for these important top predators. An intensive longline survey conducted in nearshore waters off northeastern Brazil from 2004 through 2014 caught a total of 18 bull sharks (Carcharhinus leucas) (male-female ratio = 0.63:1), which can be dangerous to humans. Although most sharks were sexually mature, there was no evidence that this region could be used as a parturition or nursery area. Prey items identified in the guts of the sharks comprised teleosts, mollusks and elasmobranchs. Additionally, one satellite-tagged bull shark covered a great distance (> 3,000 km) in 75 days at liberty, making most use of shallow waters (< 20 m depth) and presumably also entering an estuarine area. Although bull sharks are not an important fishery resource in this region, such a reduced abundance coupled with its affinity for coastal and inshore habitats highlights the potential vulnerability of C. leucas to deleterious anthropic interferences off northeastern Brazil.Keywords: Drumline, Longline, Maturity status, Pop-up satellite archival tag, Recife.Um melhor entendimento sobre a utilização de hábitat das espécies de tubarões costeiros, e como ela se sobrepõe à presença humana em regiões altamente populosas, se faz necessário a fim de subsidiar o desenvolvimento de eficientes medidas de conservação para esses importantes predadores de topo. Um estudo intensivo utilizando espinhel, conduzido em águas costeiras do nordeste do Brasil entre os anos de 2004 e 2014, capturou um total de 18 tubarões cabeça-chata (Carcharhinus leucas) (proporção macho-fêmea = 0,63:1), os quais podem ser perigosos para humanos. Apesar da maioria dos tubarões estarem sexualmente maduros, não houve evidências de que essa região esteja sendo utilizada como uma área de parto ou berçário. Entre os itens alimentares identificados foram encontrados teleósteos, moluscos e elasmobrânquios. Além disso, um tubarão cabeça-chata marcado com um transmissor satélite percorreu uma grande distância (> 3.000 km) em 75 dias em liberdade, fazendo o uso de águas superficiais (< 20 m profundidade) e presumivelmente entrando em uma área estuarina. Apesar de os tubarões cabeça-chata não corresponderem a um recurso pesqueiro importante nessa região, tal reduzida abundância juntamente com a sua afinidade por hábitats costeiros reforçam a potencial vulnerabilidade de C. leucas às interferências antrópicas deletérias ao longo da costa nordeste do Brasil.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 91%

Bioecology and movements of bull sharks, Carcharhinus leucas , caught in a long-term longline survey off northeastern Brazil

2017

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“…The shallow depth and topography are of tectonic origin and reflect the local geological conditions. The CSC off the Jaguaribe River extends over 100 km between 371 and 381W and 3140′ and 4130′ S, with depths of up to 100 m and a gentle slope of 1:670 to 1:1000 to a depth of 70 m (Arz et al, 1999;Martins and Coutinho, 1981). Where the shelf is relatively narrow, coastal currents influence the coastline and are associated with relatively low tidal current influence.…”

Section: Study Areamentioning

confidence: 98%

Continental shelf water masses off the Jaguaribe River (4S), northeastern Brazil

Dias

Castro

Lacerda

2013

Continental Shelf Research

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“…2). The Touros High is characterized by a Precambrian basement with a thin sedimentary cover which thickens towards the northern sector into the Potiguar Basin and towards the eastern sector into the Pernambuco-Paraiba Basin (MARTINS; COUTINHO, 1981;CÓRDOBA et al, 2007;PESSOA NETO et al, 2007;). The climate varies from tropical dry and semi-arid on the northern coast to tropical and humid on the eastern coast.…”

Section: Regional Settingmentioning

confidence: 99%

Characterization of the Brazilian continental shelf adjacent to Rio Grande do Norte state, NE Brazil

et al. 2010

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A B S T R A C TThis study focuses on the analysis of high-resolution seismic profiles, integrated with sedimentological, echosounder, SRTM and satellite image datasets, of the Brazilian continental shelf adjacent to the Rio Grande do Norte State, NE Brazil. Located in the northeast of Brazil, the State of Rio Grande do Norte is bounded by two main coastal and shelf systems: the eastern coastal-shelf, from the Sagi River to the Touros High, and the northern coastal-shelf, extending from Touros High to Tibau. This shelf represents a modern, highly dynamic mixed carbonate-siliciclastic system characterized by reduced width and shallow depths as compared with other parts of the Brazilian shelf. It has an average width of 40 km, the shelf-break lying at a depth of ~ 60 m. This shelf is subject to the full strength of the westerly South Equatorial current combined with high winds and moderate to high tides and waves. A sharply defined stratigraphic boundary, probably between the Pleistocene and Holocene deposits, is clearly to be observed in the seismic record. Incised-valleys extending from the main river mouths (e.g.the Potengi, Açu, and Apodi) to the shelf break dominate the area investigated and may indicate periods of lower sea level. R E S U M OEste estudo está direcionado ao conhecimento da plataforma continental brasileira adjacente ao Estado do Rio Grande do Norte, NE do Brasil, através da analise de perfis sismicos de alta resolução integrados a dados sedimentológicos, batimétricos, SRTM e imagens de satélites. O Estado do Rio Grande do Norte, localizado no nordeste do Brasil, apresenta dois sistemas costeiros-plataformais: Setor Este, do Rio Sagi (divisa PB-RN) ao Alto de Touros e Setor Norte, do Alto de Touros a Tibau (divisa RN-CE). Esta plataforma representa um sistema plataformal moderno misto (carbonático-siliciclástico), altamente dinâmico. É caracterizado por sua reduzida largura e águas rasas, quando comparado com outras partes da plataforma brasileira. A plataforma apresenta largura média de 40 km e a sua quebra encontra-se a profundidades médias de 60 m. A plataforma é sujeita a ação da corrente sul equatorial, combinada a ventos fortes e variação de maré moderada a alta e/ou ondas. Um limite estratigráfico fortemente definido, provavelmente entre os depósitos Pleistocênicos e Holocênicos, pode ser bem observado e vales incisos, estendendo-se a partir dos principais rios (como por ex., Potengi, Açu e Apodi) dominam a área investigada.

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The Brazilian continental margin

Cited by 83 publications

References 4 publications

Bioecology and movements of bull sharks, Carcharhinus leucas , caught in a long-term longline survey off northeastern Brazil

Bioecology and movements of bull sharks, Carcharhinus leucas , caught in a long-term longline survey off northeastern Brazil

Continental shelf water masses off the Jaguaribe River (4S), northeastern Brazil

Characterization of the Brazilian continental shelf adjacent to Rio Grande do Norte state, NE Brazil

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