Distribution of the South American dolphin <i>Sotalia fluviatilis</i>

Borobia, Mônica; Siciliano, Salvatore; Lodi, Liliane; Hoek, Wyb

doi:10.1139/z91-148

Cited by 105 publications

(102 citation statements)

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“…guianensis is listed as "Insufficiently Known" according to IBAMA (2001) despite its continuous distribution on the east coast of South and Central America (Borobia et al, 1991;da Silva and Best, 1994;Simões-Lopes, 1988 igratory Species) and IUCN (The World Conservation Union). Rosas (2006) suggested the classification of the Estuarine Dolphin as "vulnerable' in the IUCN red list, due to intensive bycatches and marine pollution.…”

Section: Estuarine Dolphin Sotalia Guianensismentioning

confidence: 99%

Cetacean diversity on the Parnaiba Delta, Maranhão state, northeastern Brazil

Ch²,

Rg³

et al. 2008

Braz. J. Biol.

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The increase in the research of cetacean surveys on the Brazilian coast has brought new data on the distribution of species never reported before. The present work reviews the current knowledge on cetaceans species and extends this knowledge with an analysis of cetaceans stranded in the Parnaiba Delta, on the coast of Maranhão State, Brazil. The studies on cetacean diversity on the coast of the Parnaíba Delta were made from August 2004 to August 2006. Fourteen strandings were reported, representing six distinct species, such as the estuarine dolphin (Sotalia guianensis), humpback whale (Megaptera novaeangliae), Bryde's whales (Balaenoptera edeni), dwarf minke whale (Balaenoptera acutorostrata), pigmy killer whale (Feresa attenuata), sperm whale (Physeter macrocephalus) and two specimens which have not yet been identified. The significant degree of cetacean diversity in the region shows that the Parnaíba Delta is, possibly, of an important area for cetacean studies in Brasil.Keywords: cetacean, stranding, Parnaiba Delta, Maranhão, Brazil. Diversidade de cetáceos no Delta do Parnaíba, estado do Maranhão, nordeste do Brasil ResumoCom o aumento das pesquisas voltadas para o monitoramento de cetáceos no litoral brasileiro, registros inéditos sobre a distribuição de espécies têm sido realizados, ampliando o conhecimento sobre áreas de ocorrência dos cetáceos no Brasil. O presente estudo teve por objetivo realizar um levantamento das espécies de cetáceos encalhadas no Delta do Parnaíba, MA. Os estudos foram realizados através de entrevistas com comunidades locais e por meio de coleta direta, entre agosto de 2004 e agosto de 2006. Foram registrados 14 encalhes de cetáceos, com representantes de 6 espécies distintas, até então desconhecidas para a região do Delta do Parnaíba com um exemplar não identificado. Dentre as espécies registradas foram encontrados cinco exemplares do boto-cinza (Sotalia guianensis), um exemplar de baleia-jubarte (Megaptera novaeangliae), três exemplares de baleia-de-bryde (Balaenoptera edeni), um exemplar de baleia-minke-anã (Balaenoptera acutorostrata), um exemplar de orca-pigméia (Feresa attenuata), dois exemplares de cachalote (Physeter macrocephalus) e dois exemplares não identificados que correspondem a um crânio de misticeto e uma escápula de um possível filhote de odontoceto. A significativa diversidade na região do Delta do Parnaíba indica sua relevância para os estudos de cetáceos no Brasil. As análises de idade, baseadas em análises de suturas ósseas dos exemplares encalhados mostram que a região deltaica pode ser utilizada como área de reprodução por algumas espécies como Sotalia guianensis e Balaenoptera edeni.Palavras-Chave: cetáceos, encalhes, Delta do Parnaíba, Maranhão, Brasil. Magalhães, FA. et al.

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Section: Estuarine Dolphin Sotalia Guianensismentioning

confidence: 99%

Cetacean diversity on the Parnaiba Delta, Maranhão state, northeastern Brazil

Ch²,

Rg³

et al. 2008

Braz. J. Biol.

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“…Coastal and river dolphins are threatened by a range of human activities (Borobia et al 1991;Thompson et al 2000;Kreb and Budiono 2005;Cantor et al 2012), and several species (i.e. vaquita, Phocoena sinus; Hector's dolphin, Cephalorhynchus hectori) are now among the world's most threatened mammals (Rojas-Bracho et al 2006;Reeves et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Estimates of abundance and apparent survival of coastal dolphins in Port Essington harbour, Northern Territory, Australia

et al. 2014

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Abstract, and grey shading in the table). The errors were due to transcription error and in no way affect the outcome and conclusions of the study. AbstractKey results. Abundance estimates for the three species varied across the sampling periods, with the estimated number of Australian snubfin dolphins ranging from 136 (s.e. 62) to 222 (s.e. 48); from 48 (s.e. 17) to 207 (s.e. 65) for the Australian humpback dolphin; and 34 (s.e. 16) to 75 (s.e. 26) for the bottlenose dolphin. AbstractContext. Three dolphin species occur in coastal waters of monsoonal northern Australia: the Australian snubfin (Orcaella heinsohni), humpback (Sousa sp.) and the bottlenose (Tursiops sp.). Their overall population size and trends are poorly known, and their conservation status has been difficult to resolve, but can be expected to deteriorate with likely increased development pressures.Aims. We sought to provide an estimate of abundance, and apparent survival, of the three dolphin species at the largely undeveloped harbour of Port Essington (325 km 2 ), Northern Territory, with repeated sampling over a 2.9-year period. Given increasing obligations to undertake population assessments for impact studies at proposed development sites, we assess the strengths and limitations of a systematic sampling program.Methods. We used photo-identification data collected during systematic boat-based transect surveys undertaken from 2008 to 2010 and Pollock's robust capture-recapture design model. Key results. Total abundance estimates for the three species were variable across different sampling periods. The estimated number of individuals in the sampled area varied per sampling episode from 136 (s.e. 62) to 222 (s.e. 48) for snubfin, from 48 (s.e. 7) to 207 (s.e. 14) for humpbacks and from 34 (s.e. 6) to 75 (s.e. 9) for bottlenose dolphins. Apparent survival was estimated for snubfin at 0.81 (s.e. 0.11), humpbacks at 0.59 (s.e. 0.12) and bottlenose at 0.51 (s.e. 0.17) per annum.Key conclusions.(1) The values derived here provide some of the only estimates of local population size for these species across monsoonal northern Australia; (2) population-size estimates varied considerably among seasons or sampling episodes; (3) the low apparent survival probabilities indicated that many individuals may move at scales larger than the study area; (4) density of snubfin and humpback dolphins in the present study area exceeded the few other estimates available for these species elsewhere in Australia.Implications. The present study provided the first baseline estimates of abundance and apparent survival for three coastal dolphin species in monsoonal northern Australia. Such information is becoming increasingly important as development pressures intensify in coastal areas. Sampling protocols for future monitoring and impact assessment need an enhanced consideration of seasonality and scale issues.

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“…Some of these species are globally distributed, such as the sperm whale, Physeter macrocephalus (Linnaeus, 1758), bottlenose dolphin, Tursiops truncatus (Montagu, 1821), and killer whale, Orcinus orca (Linnaeus, 1758) (Jefferson et al 1993). Other species, on the other hand, have a more restricted distribution, such as Guiana dolphins, Sotalia guianensis (Van Benédén, 1864) (Borobia et al 1991) and franciscanas, Pontoporia blainvillei (Gervais & d' Orbigny, 1844) (CresPo et al 1998, Netto & Siciliano 2007.…”

mentioning

confidence: 99%