[MARMAM] New Article: Franciscana dolphins found in inner estuarine waters in Brazil.

Marcos Santos sotalia at gmail.com
Sun Apr 19 18:54:39 PDT 2009

Dear Marmamers:

The following manuscript on the discovery of a new population of La Plata
dolphins (Pontoporia blainvillei) in inner estuarine waters of Brazil was
recently published.

Pdf file available: requests to sotalia at gmail.com.

Santos, M.C. de O.; Oshima, J.E.F. & da Silva, E. 2009. Sightings of
franciscana dolphins (Pontoporia blainvillei): the discovery of a polulation
in the Paranagua Estuarine Complex, southern Brazil. Brazilian Journal of
Oceanography, 57(1): 57-63.

ABSTRACT: Franciscana dolphins (*Pontoporia blainvillei*)* *are small
cetaceans distributed along coastal Atlantic waters of South America from
Itaúnas (18º25’S), Brazil, to Golfo Nuevo, Argentina; usually found in
shallow, turbid waters, out to the 30 m isobath on the continental shelf,
generally associated with estuarine and riverine discharges. The species is
considered as a particular conservation concern because of its restricted
distribution and vulnerability to incidental captures in fishing gear. Most
of the information gathered on the species biology came from studies of dead
individuals found stranded or incidentally captured in fishing operations,
as *P. blainvillei *is difficult to be sighted in its habitat. However,
several sightings made within the area of the species´ distribution have
been described. Franciscana dolphins were sighted during boat surveys
undertaken to evaluate ecological aspects of Guiana dolphins (*Sotalia
guianensis*) in inner estuarine waters of southern and Brazil (~25o30’S) in
2007-2008. Ten franciscana sightings are reported in the Paranagua Estuarine
Complex (PEC). Group sizes varied from 2 to 12 individuals. Water depth
where sightings occurred varied from 3.8 to 13.4 m and water transparency
from 1.3 to 2.5 m. In winter, water salinity ranged between 30 to 31 ppm and
its superficial temperature ranged from 16oC to 20oC. In summer, these
values were 10 ppm and 27oC, respectively. Adult individuals presented films
of algae attached to their bodies. Five individuals presented
distinguishable marks on the top or on the posterior border of the dorsal
fin, including one female observed in two distinct seasons. Franciscana
groups were observed in close proximity to Guiana dolphins (*ca.* 20 m) on
several occasions, but no interactions between them were seen. The presence
of franciscana dolphins in the PEC reinforces the importance of the Lagamar
estuary for biodiversity conservation. Efforts should be directed towards a
detailed investigation into population parameters, giving emphasis to
abundance, use of area, and the evaluation of whether calves are present all
year round, which could constitute important evidence as to the use of the
area as a breeding site.

Marcos C.


Dr Marcos César de Oliveira Santos

Laboratório de Ecologia de Mamíferos
Programa de Pós-Graduação em Biologia:
Diversidade e Manejo de Vida Silvestre
Universidade do Vale do Rio dos Sinos (UNISINOS),
Avenida Unisinos, 950,
São Leopoldo, RS, Brasil, 93022-000
E-mail: mcos at unisinos.br
Telefone/Phone: 51-3590-1229


Projeto Atlantis, Laboratório de Biologia da Conservação de Cetáceos
Programa de Pós-Graduação em Zoologia, Departamento de Zoologia, Instituto
de Biociências,
Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Campus Rio
Av 24-A, 1515, Bela Vista, Rio Claro, SP, Brasil, 13506-900.
E-mail: sotalia at rc.unesp.br

Endereço Residencial/Home Address:
Rua João Alfredo Panitz, 204, apto 602,
Centro, São Leopoldo, RS
E-mail: sotalia at gmail.com
Telefone/Phone: 3037-2128
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