Incidental mortality of franciscana dolphin (Pontoporia blainvillei) in Argentina

Cappozzo, Humberto Luis; Negri, María Fernanda; Pérez, Fabián; Albareda, Diego; Monzon, Federico Castro; Corcuera, J. F.

doi:10.5597/lajam00118

Cited by 35 publications

(40 citation statements)

References 8 publications

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“…In addition, the CPUE values estimated in the period 1992-1993 for the same localities by and in the period 1998-2003 by CAPPOZZO et al (2007) were recalculated for each kind of fishing gear in order to permit comparison with our data.…”

Section: Methodsmentioning

confidence: 99%

“…Finally, Figures 2 and 3 show the current fishing effort and CPUE estimates (2006-2009, this study) as compared with previous ones of Southern Buenos Aires province CAPPOZZO et al, 2007). In the period 1992-1993, the artisanal fleet operated with gillnets of 180-360 mm mesh size targeting tope sharks, with a franciscana bycatch of 130 dolphins in gillnets and 85 in shrimper gear .…”

Section: Franciscana Dolphin Incidental Mortalitymentioning

confidence: 99%

“…In that period, some 340-350 dolphins were bycaught annually, mainly in 300 mm mesh size gillnets and "tapacanal" gillnets that blocked estuarial channels. Recently, new estimates have shown that in Argentina, 400-600 franciscana dolphins have been killed every year by artisanal fisheries ALBAREDA, 2004;CAPPOZZO et al, 2007). However, because of the changing dynamics of fisheries, a re-evaluation of the franciscana dolphin bycatch and the fishing effort involved is necessary over the years.…”

Section: Introductionmentioning

confidence: 99%

“…The franciscana dolphin inhabits coastal waters of the Southwestern Atlantic Ocean, from Espírito Santo, Brazil (18º25'S, 30º42'W), to Chubut, Argentina (42º35'S, 64º48'W) (SICILIANO, 1994;CRESPO et al, 1998;BASTIDA et al, 2007). Since 2008, it has been included in the category "vulnerable" to extinction by the International Union for the Conservation of Nature (REEVES et al, 2008), mainly because of the high levels of bycatch that this species has faced over the last two decades throughout its area of distribution (ROSAS et al, 2002;DI BENEDITTO, 2003;SECCHI et al, 2004;CAPPOZZO et al, 2007;FRANCO-TRECU et al, 2009). Moreover, some of the prey items of the franciscana dolphin, such as the croacker Micropogonias furnieri and the striped weakfish Cynoscion guatucupa are important coastal resources presenting evidence of overexploitation and stock depletion in the Argentinian-Uruguayan fishing area and off southern Brazil (RUARTE, 2001;RODRIGUEZ et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Bycatch of franciscana dolphins Pontoporia blainvillei and the dynamic of artisanal fisheries in the species' southernmost area of distribution

Negri¹,

Denuncio

Panebianco³

et al. 2012

Braz. j. oceanogr.

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In Argentina, the franciscana dolphin is one of the most vulnerable cetaceans regularly entangled in coastal artisanal fishery nets. The aim of this paper is to estimate the species' incidental mortality on the Southern coast of Buenos Aires province through interviews with the captains of artisanal fishing vessels, in the period 2006-2009. Franciscana bycatch was reported for gillnets and shrimper gear all year round but it occurred more frequently between October and February, at 5 km offshore and 10-20 m depth. The estimated mean annual incidental mortality was 107 dolphins (CI 95% = 87-129), 92 caught in gillnets (CI 95% = 73-112) and 15 in shrimpers' gear (CI 95% = 8-25) with a capture per unit effort of 0.029 dolphins per km of gillnet (CI 95% = 0.023-0.036) and 0.022 per shrimpe r's net (CI 95% = 0.012-0.035). Annual fluctuations were due to differences in the number of gillnetting fishing days. If mortality estimates for the Northern coast are also taken into account, values attain a maximum of 360-539 dolphins bycaught in the entire Buenos Aires province, representing 2.5-3.7% of the species' abundance in Argentina. This will inevitably lead to the decline of franciscana dolphin populations in the near future unless alternative fishing grounds are identified and alternative gearadopted.

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Section: Methodsmentioning

confidence: 99%

Section: Franciscana Dolphin Incidental Mortalitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Bycatch of franciscana dolphins Pontoporia blainvillei and the dynamic of artisanal fisheries in the species' southernmost area of distribution

Negri¹,

Denuncio

Panebianco³

et al. 2012

Braz. j. oceanogr.

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“…Accidental capture in fishing nets is the main conservation issue for the species (SECCHI et al, 1997;KINAS, 2002;ROSAS et al, 2002;DI BENEDITTO, 2003;SECCHI et al, 2004;CAPOZZO et al, 2007). Hundreds of franciscana dolphins die each year as a consequence of getting entangled in gillnets.…”

Section: Introductionmentioning

confidence: 99%

Franciscana strandings on the north coast of Santa Catarina State and insights into birth period

et al. 2013

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Resumo Encalhes de toninhas no litoral norte de Santa Catarina e informações sobre o período de nascimento.A toninha (Pontoporia blainvillei) é o pequeno cetáceo mais ameaçado do Atlântico Sul Ocidental. A captura acidental em redes de pesca é o maior problema para esta espécie ao longo de sua distribuição. As toninhas mortas encontradas nas praias são uma importante fonte de informações. O objetivo deste trabalho foi analisar os registros de carcaças de toninhas encontradas mortas no litoral norte de Santa Catarina, incluindo a Baía da Babitonga. Entre janeiro de 2001 e novembro de 2012 foram registradas 54 carcaças de toninhas. Entre os meses de agosto e outubro foram registradas 28 carcaças (52%), sendo que o número mais elevado (oito indivíduos) foi encontrado em 2011. Levando em conta que estas informações não são decorrentes de um esforço sistematizado, não podemos considerar que esta seja uma estimativa de mortalidade. O maior animal registrado foi uma fêmea, com 142 cm de comprimento. Dentre os animais recuperados, 10 (18,5%) tinham comprimento total inferior a 80 cm, sendo considerados fetos ou filhotes. Estes registros indicam que o principal período de nascimento de toninhas em Santa Catarina é de outubro a janeiro. As informações aqui apresentadas contribuem para o conhecimento desta espécie no Estado. and November 2012, 54 franciscana carcasses were recorded, with the highest number (8 individuals) in 2011. Fifty-two percent (n=28) of the carcasses were recorded between August and October. Taking into account that this information was not obtained from a systematic effort, it was not possible to consider this as an estimation of mortality. The largest animal was a female, with a total length of 142 cm. Ten recovered animals (18.5%) were smaller than 80 cm, and were considered fetuses or calves. These records indicate that the main birthing period for franciscanas in Santa Catarina is between October and January. The findings presented here contribute to our knowledge of franciscana ecology in the state of Santa Catarina.

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Patterns of population structure at microsatellite and mitochondrial DNA markers in the franciscana dolphin (Pontoporia blainvillei)

Gariboldi

Túnez

Failla³

et al. 2016

Ecology and Evolution

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The franciscana dolphin, Pontorporia blainvillei, is an endemic cetacean of the Atlantic coast of South America. Its coastal distribution and restricted movement patterns make this species vulnerable to anthropogenic factors, particularly to incidental bycatch. We used mitochondrial DNA control region sequences, 10 microsatellites, and sex data to investigate the population structure of the franciscana dolphin from a previously established management area, which includes the southern edge of its geographic range. F‐statistics and Bayesian cluster analyses revealed the existence of three genetically distinct populations. Based on the microsatellite loci, similar levels of genetic variability were found in the area; 13 private alleles were found in Monte Hermoso, but none in Claromecó. When considering the mitochondrial DNA control region sequences, lower levels of genetic diversity were found in Monte Hermoso, when compared to the other localities. Low levels of gene flow were found between most localities. Additionally, no evidence of isolation by distance nor sex‐biased dispersal was detected in the study area. In view of these results showing that populations from Necochea/Claromecó, Monte Hermoso, and Río Negro were found to be genetically distinct and the available genetic information for the species previously published, Argentina would comprise five distinct populations: Samborombón West/Samborombón South, Cabo San Antonio/Buenos Aires East, Necochea/Claromecó/Buenos Aires Southwest, Monte Hermoso, and Río Negro. In order to ensure the long‐term survival of the franciscana dolphin, management and conservation strategies should be developed considering each of these populations as different management units.

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Incidental mortality of franciscana dolphin (Pontoporia blainvillei) in Argentina

Cited by 35 publications

References 8 publications

Bycatch of franciscana dolphins Pontoporia blainvillei and the dynamic of artisanal fisheries in the species' southernmost area of distribution

Bycatch of franciscana dolphins Pontoporia blainvillei and the dynamic of artisanal fisheries in the species' southernmost area of distribution

Franciscana strandings on the north coast of Santa Catarina State and insights into birth period

Patterns of population structure at microsatellite and mitochondrial DNA markers in the franciscana dolphin (Pontoporia blainvillei)

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