Report of the Working Group on Major Threats and Conservation

Crespo, Enrique A.; Alarcon, Daniela Trigueirinho; Alonso, Mariana B.; Bazzalo, Mariel; Borobia, Mônica; Filla, Gislaine de Fatima; Lodi, Liliane; Magalhães, Fagner; Marigo, Juliana; De, Helder Lima; Reynolds, John E.; Schaeffer, Yara; Lailson‐Brito, José; Wetzel, Dana L.

doi:10.5597/lajam00153

Cited by 24 publications

(29 citation statements)

References 45 publications

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“…Pollock's Robust cling Cananeia Island, extending approximately Design Model combines advantages of closed 12 km northwards (Figure 1). To simultaneously and open models, providing more reliable and cover the entire estuarine area where dolphins accurate estimates (Kendall et al, 1995). The use can be found, the total area was divided into three of this model requires a specific survey design; smaller sub-areas.…”

Section: Baseline Demographic Information Is Essentialmentioning

confidence: 99%

“…We assumed that capture (p) and recapture (c) Mark-recapture analyses were carried out probabilities were equal (p = c) as the probability using Pollock's robust design (RD) framework of recapturing a dolphin is unlikely to have been (Pollock, 1982;Kendall et al, 1995Kendall et al, , 1997 affected by the initial capture since the individuwithin MARK (White & Burnham, 1999). The als are not physically captured or handled (Boyd RD combines open and closed population et al, 2010).…”

Section: Mark-recapture Analysismentioning

confidence: 99%

“…cific time (t) is conditional on whether the same Each primary sampling session consists of sevindividual was available (y'') or unavailable (y') eral secondary capture periods that are close in at time t-1; while in random temporary emigratime, thus making the assumption of closure tion, being temporarily unavailable for capture in acceptable (Kendall et al, 1995(Kendall et al, , 1997. In the the area in time (t) is independent of the individpresent study, the three primary periods (seaual's availability in the previous sampling period sons) were divided into 18 to 19 distinct second- (Kendall et al, 1997).…”

Section: Mark-recapture Analysismentioning

confidence: 99%

“…RD models logistical support. Cetacean Society International, yield reliable estimates of apparent survival rates in Earthwatch Institute, Fundação de Amparo à the presence of transients and capture heterogene-Pesquisa do Estado de São Paulo (FAPESP Process ity (Pollock, 1982;Kendall et al, 1995).…”

Section: Total Population Sizementioning

confidence: 99%

See 3 more Smart Citations

Abundance Estimates of Guiana Dolphins (Sotalia guianensis; Van Bénéden, 1864) Inhabiting an Estuarine System in Southeastern Brazil

Mello¹,

Molina²,

Kajin³

et al. 2019

Aquat Mamm

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Section: Baseline Demographic Information Is Essentialmentioning

confidence: 99%

Section: Mark-recapture Analysismentioning

confidence: 99%

Section: Mark-recapture Analysismentioning

confidence: 99%

Section: Total Population Sizementioning

confidence: 99%

See 2 more Smart Citations

Abundance Estimates of Guiana Dolphins (Sotalia guianensis; Van Bénéden, 1864) Inhabiting an Estuarine System in Southeastern Brazil

Mello¹,

Molina²,

Kajin³

et al. 2019

Aquat Mamm

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“…Devido ao hábito essencialmente costeiro de S. guianensis, ameaças como capturas acidentais em operações de pesca, perda de habitat resultante da construção de marinas e portos, poluição química e sonora e sobreexploração dos recursos vivos marinhos, tornam a espécie vulnerável(CRESPO et al, 2010). Embora haja um progresso em relação ao maior conhecimento da história de vida de S. guianensis, a espécie ainda está Estimar idades em cetáceos odontocetos é um passo fundamental para compreender nuances importantes relacionadas ao ciclo de vida de suas populações como, por exemplo, inferir sobre as idades de maturidade sexual e física, longevidade média e estrutura etária(HOHN et al, 1989).…”

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Idade e crescimento da toninha (<i>Pontoporia blainvillei</i>) e do boto-cinza (<i>Sotalia guianensis</i>) de águas costeiras do sul de São Paulo e norte do Paraná

Conversani¹

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Abundance and effect of health status on apparent survival of Guiana dolphins,Sotalia guianensis, in an open embayment in north‐eastern Brazil

Meirelles

Choi‐Lima²,

Nova³

et al. 2022

Aquatic Conservation

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1. Guiana dolphins (Sotalia guianensis) inhabit shallow waters of the tropical western Atlantic, an area that is now mostly occupied by cities and harbours. Demographic studies have been concentrated in sheltered areas of south/south-eastern Brazil.2. This study investigated site fidelity and estimated population abundance and apparent survival of Guiana dolphins in Mucuripe Embayment (ME), on the northeastern Brazilian coast, through photo-identification surveys and closed and open population mark-recapture models, from October 2009 to September 2011.3. Forty-six Guiana dolphin groups were recorded (in groups of between one and eight dolphins, with a mean ± SD of 3.49 ± 2.33) in 27 out of 40 surveys. Twentyfive animals were photo-identified, with eight considered to have a 'poor health' status. The standardized site fidelity index (SSFI) was low (0.25).4. Using the program CAPTURE, the time and heterogeneity model (M th ) resulted in a total abundance estimate of 39, with a Coefficient of Variation (CV) of 21% (95% CI 35-80%). In PROGRAM MARK, model averaging resulted in a total abundance estimate of 33 (CV 32%, 95% CI 30-100%). Using a CV of 21%, the power to detect a decline of 50% during the study period was 0.44 and the power to detect a decline of 5% a year was 0.11. To detect these declines with a 0.90 power, 12 years of monitoring would be necessary.5. The annual adult apparent survival rate was low (0.71; CV 19%; 95% CI 0.40-0.90), and differed for dolphins in 'good' (0.64; CV 28%, 95% CI 0.27-0.89) and 'poor' (0.85; CV 22%; 95% CI: 0.23-0.99) health.6. The low abundance of Guiana dolphins in ME indicates that conservation actions should start immediately, such as creating a marine protected area, continuing awareness campaigns, using by-catch reduction technologies, developing new regulations, and promoting law enforcement. Monitoring studies must continue with increased effort to reduce uncertainty in estimates and to improve the power to detect trends of decline.

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Report of the Working Group on Major Threats and Conservation

Cited by 24 publications

References 45 publications

Abundance Estimates of Guiana Dolphins (Sotalia guianensis; Van Bénéden, 1864) Inhabiting an Estuarine System in Southeastern Brazil

Abundance Estimates of Guiana Dolphins (Sotalia guianensis; Van Bénéden, 1864) Inhabiting an Estuarine System in Southeastern Brazil

Idade e crescimento da toninha (<i>Pontoporia blainvillei</i>) e do boto-cinza (<i>Sotalia guianensis</i>) de águas costeiras do sul de São Paulo e norte do Paraná

Abundance and effect of health status on apparent survival of Guiana dolphins,Sotalia guianensis, in an open embayment in north‐eastern Brazil

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