scholarly journals Incidental mortality of franciscana dolphin (Pontoporia blainvillei) in Argentina

Author(s):  
H. L. Cappozzo ◽  
M. F. Negri ◽  
F. H. Pérez ◽  
D. Albareda ◽  
F. Monzón ◽  
...  
2002 ◽  
Vol 18 (4) ◽  
pp. 833-842 ◽  
Author(s):  
P. Bordino ◽  
S. Kraus ◽  
D. Albareda ◽  
A. Fazio ◽  
A. Palmerio ◽  
...  

2012 ◽  
Vol 60 (2) ◽  
pp. 149-158 ◽  
Author(s):  
María Fernanda Negri ◽  
Pablo Denuncio ◽  
María Victoria Panebianco ◽  
Humberto Luis Cappozzo

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.


Author(s):  
Haydée A. Cunha ◽  
Teresa E. C. dos Santos ◽  
Luísa C. Alvarenga ◽  
Nathalia P. Cavaleiro ◽  
Marta J. Cremer ◽  
...  

2008 ◽  
Vol 100 (1) ◽  
pp. 119-122 ◽  
Author(s):  
L. Heinzelmann ◽  
P. C. Chagastelles ◽  
D. Danilewicz ◽  
J. A. B. Chies ◽  
J. Andrades-Miranda

2014 ◽  
Vol 86 (3) ◽  
pp. 1221-1226 ◽  
Author(s):  
MARTA J. CREMER ◽  
CAMILA M. SARTORI ◽  
BEATRIZ SCHULZE ◽  
RENAN L. PAITACH ◽  
ANNELISE C. HOLZ

On October 2011, a newborn franciscana dolphin with an anomalously coloration was sighted in Babitonga Bay, southern Brazil. The calf was totally white. Besides the potential mother and newborn, the group also had the presence of another adult, who always was swimming behind the pair. Both adults had the typical coloration of the species, with the back in grayish brown. The group, composed by the white franciscana calf, his pontential mother and one more adult, was reported in five occasions. The group was always in the same area where it was first recorded and showed the same position during swimming. Between first and last sighting of the white calf (113 days) the color has not changed. This is the first case of a white franciscana dolphin. This coloration has never been reported despite the high number of dead franciscanas recovered each year along the distribution of the species, resulting from accidental capture in fishing nets. This fact leads us to believe that this is a very rare characteristic for this species. We considered the possibility that this franciscana could be an albino dolphin.


Author(s):  
Manuela Bassoi ◽  
Eduardo R. Secchi ◽  
Daniel Danilewicz ◽  
Ignacio B. Moreno ◽  
Roberta A. Santos ◽  
...  

Abstract The franciscana dolphin (Pontoporia blainvillei) is a coastal dolphin endemic to the western South Atlantic Ocean. The dolphin is listed as vulnerable in the IUCN Red List, with incidental catches in gillnet fisheries the greatest conservation concern for this species. Insights into the feeding habits of this dolphin are essential to understand its distribution, movements and use of habitat, which are fundamental for effective management of the species. The feeding habits of franciscana dolphins were investigated from analyses of stomach contents of animals incidentally caught by two fishing operations from southern and northern regions of the southern Brazilian coast. In this study we investigate the existence of intrapopulation (sexual maturity and sex-related) variation in the diet of the franciscana dolphin, evaluating the spatial (northern and southern geographic areas) and seasonal influences. The analyses were based on Linear and Generalized Linear Models (LM and GLM). The majority of identified prey species were bottom-dwelling teleosts and the squid Doryteuthis sanpaulensis. The most important prey differed spatially and seasonally between northern and southern regions of the study area, and our results revealed significant differences between sexes and sexual maturity stages, mainly related to prey species sizes. This variation might indicate differences in prey selection, availability or habitat use patterns among these groups. In any case, these dietary differences are likely to minimize intraspecific competition for food resources, and/or indicate spatio-temporal variation in prey availability.


Author(s):  
Laura Busin Campos ◽  
Xênia Moreira Lopes ◽  
Ednilson da Silva ◽  
Marcos César de Oliveira Santos

AbstractThis study evaluated the feeding habits of the franciscana dolphin (Pontoporia blainvillei) in south-eastern Brazil. Stomach contents were collected from a total of 145 dead specimens found incidentally caught by fishing vessels or stranded between 2005 and 2015. Fish otoliths, cephalopod beaks and whole non-digested prey were used for prey species identification. A total of 9337 prey items were identified, including 26 species of teleost fishes and three species of cephalopods. The most important prey families were Sciaenidae among fish and Loliginidae among cephalopods. Franciscana dolphins tended to feed on small fish (mean = 5.25 cm) and cephalopods (mean = 8.57 cm). The index of relative importance (IRI) showed that Pellona harroweri and Doryteuthis plei were the most important prey for both males and females. The PERMANOVA test confirmed that there is no significant difference between the feeding habits of different sexes, but detected a significant difference among seasons. Overall, our results show that franciscana dolphins are predominantly ichthyophagous and non-selective in relation to the type of prey, feeding on pelagic, demersal and pelagic-demersal prey.


2019 ◽  
Vol 35 (2) ◽  
pp. 718-721
Author(s):  
Javier S. Tellechea ◽  
Martin Lima ◽  
William Perez

Sign in / Sign up

Export Citation Format

Share Document