Monitoring
the incidental mortality of cetaceans in the artisanal fishery of Baixada
Santista (SP, Brazil)
with
emphasis on the Franciscana (Pontoporia blainvillei) by
MSc.
Carolina P. Bertozzi, Dr. Valéria Ruoppolo, Juliana Marigo, Érica
Barbosa and Janaína Ribeiro
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Introduction
and background
The identity of the franciscana
stocks has been recently clarified and recently biological and genetic
evidences led to the establishment of four management areas (hereafter
referred to as FMA [Franciscana Management Areas] 1 to 4) (Secchi et al.,
2001). Recent studies have proved that monitoring of franciscana mortality
is imperative for the conservation of the species and results have provided
substantial information for improving the management of the species. Monitoring
fishing activities is also important for its conservation, to obtain fresh
specimens for life history, pathological analyses, stock identity, and
several other biological studies.
This project represents
the first long term monitoring of franciscana mortality in fishing gear
in São Paulo State, which is FMA2, the less known among all franciscana
management areas. And only with long term data we will be able to estimate
franciscana by-catch and season/areas of greater mortality. |
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Since late 1998, the artisanal
fishing community of ‘Boutique dos Pescadores, in Praia Grande (24º00’S
e 46º24’W) has been monitored in order to obtain information on the
characteristics of the fishing fleet and levels of incidental mortality
of marine mammals (Bertozzi and Zerbini, 2002).
The monitoring efforts was
extended in January 2001 to “Ocian” fishery community (located south of
Praia Grande) and in January 2002 to the Mongaguá community. A total
of 15 fishing boats are monitored right now, 6 in “Boutique de Peixes”,
7 in “Ocian” and 2 in “Mongaguá”, in the central coast of São
Paulo State. This area is also known as “Baixada Santista”, and it is characterized
by being highly urbanized, with highly populated areas, such as the cities
of São Vicente, Santos and Cubatão. The area is also recognized
by the most important Brazilian harbor, located in Santos, and one of the
biggest iron and steel industry areas of the country, the Cubatão
pole (CETESB, 1985).The region of Baixada Santista is one of the most productive
marine ecosystems of the brazilian coast. Despite the intense pollution,
still is a zone of production and growth of many species of commercial
interest (Secretaria de Agricultura e Abastecimento, 1989).
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Fisheries
monitoring |
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The fishing communities
studied here are essentially artisanal, with small boats (length: 5.8 -
7.8m) that do not have any navigational equipment or mechanization. Preliminary
information indicates that fishermen use primarily gillnets and that target
species are commercial valuable fish of the families Sciaenidae, Carangidae,
Mugilidae, Centropomidae and some species of sharks. During the first year
of regular monitoring, the franciscana was the only cetacean taken as bycatch
in the fishery of Praia Grande. Other species (e.g. Atlantic spotted dolphins,
Stenella frontalis, and rough toothed dolphins, Steno bredanensis [Bertozzi
and Zerbini, 2001]) have been regularly reported in the area, but none
were found entangled during the study period. There is no evidence to suggest
that franciscanas are intentionally taken in Praia Grande. The species
has no commercial value and is not used as bait, or for human or animal
consumption, as it is in other areas. |
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The fishery is monitored
regularly through interviews with fishermen and onboard observations whenever
possible (Figure 4). Information about the fishery is obtained according
to the recommendations of the International Whaling Commission Scientific
Committee (IWC, 1994 - Annex E). These include data on gear characteristics,
effort, fishing operations, and composition of target and not target species
in the captures. Catch per unit of effort (CPUE) is calculated as a function
of the size of the net and the time it spends in the water. It is expressed
as the number of individuals captured x 1000/(km x day). CPUE indexes is
stratified according to the fishing gear and season. The fishering operations
at Praia Grande and Mongaguá occur throughout the year. Net types
used varied presenting therefore its own dynamics. Increase in the total
fishing effort is observed in summer months (november, december and january)
and is related to the greater search for fish because of the presence of
tourists in the region and better sea conditions.
Fishermen also receive disposable
photographic cameras to document entanglement events and sighting of cetaceans
or any other unusual animal. Fishing boats also receive copies of the government
permit issued to the researchers to collect entangled animals and therefore
they are in compliance with the local legislation.
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Biological
samples |
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Cetacean captured alive
are released from the nets, while dead animals are landed for biological
studies. They are measured and sampled according to Norris (1961) and Geraci
and Lounsbury (1993). Necropsies are performed by a team of biologists
and veterinarians at the College of Veterinary Medicine in the University
of São Paulo (FMVZ-USP).
The samples taken on necropsies
are being held at the LAPCOM marine mammal tissue bank that has been developed
by and is maintained at Laboratório de Patologia Comparada de Animais
Selvagens, Universidade de São Paulo (LAPCOM-VPT-FMVZ-USP), coordinated
by three major researchers (two of them belonging to the NGO BioPesca).
Which the goal is to provide long-term storage of tissue samples, histological
slides, pathogens and images originated from the material for current and
future studies (Ruoppolo et al., 2002). Investigations on the diseases
affecting franciscanas is been performed for the first time (see Pathology
in Danilewicz et al., 2002). Osteological material is being held at the
Museu de Zoologia, Universidade de São Paulo. Intestines are being
analyzed for metazoan parasites that can be used for franciscana stock
identity studies (Marigo et al., 2002 A and B; Secchi et al., 2002). Fixed
brains are being studied aiming to describe de anatomy of the blood supply
in franciscanas. Subsamples of different organs have already been sent
to other research projects for analyses of DNA, virus, bacteria, contaminants,
reproduction and osteological studies.
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Environmental
education |
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It is important to carry
out environmental education and divulging work on several levels, ranging
from the fishermen to their communities, and the local population. A continuous
divulging work is carried out with the fishing community focusing on encouraging
the fishermen to interact with researchers by showing them the importance
of their cooperation to improve the conservation of protected species.
The daily contact of researchers and fishermen communities allows them
to learn and participate effectively on the study. Newspapers, magazines,
pictures and other project results are constantly presented to the fishermen.
Exhibitions destined to
the general public are conducted during the months where tourists visit
the region (austral summer) to bring to the general public's attention
the natural world and its problems, aiming to develop values and feelings
of concern for the nature and motivation for people's participation in
environmental improvement and protection.
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Dr. Valéria
Ruoppolo
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MSc. Carolina
P. Bertozzi
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Juliana
Marigo
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Foundation
of the non governmental organization Projeto BioPesca
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In 2002, aiming to legalize
the development of our project we founded the non governmental organization
Projeto BioPesca. Our main objective is to encourage research and the conservation
of the brazilian marine fauna, with special emphasis in the franciscana
and marine turtles. The NGO Projeto BioPesca is coordinated by the
following researchers: |
MSc. Carolina
P. Bertozzi (Biologist), Dr. Valéria
Ruoppolo, Juliana Marigo (DVM), Érica
Barbosa (Biologist) and Janaína Ribeiro
(Biologist).
Other affiliated researchers
and people from the local communities belong to the institution. The foundation
of the NGO Projeto BioPesca and the continuity of the research projects
developed were only accomplished because of the support given by yaqu
pacha and FAPESP (Fundação de Apoio à Pesquisa
do Estado de São Paulo). |
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