Biology Reference
In-Depth Information
I
NTRODUCTION
The taxonomy and systematic of
Sotalia
has been reassessed and changed. Until recently,
it was considered mono-specific (
Sotalia fluviatilis
) having two subspecies (geographical
forms or ecotypes), a marine one distributed from Nicaragua (Carr & Bonde, 2000) to Santa
Catarina in Brazil (Simões-Lopes, 1988) and a second, fluvial one found in the Amazon river
basin (Borobia et al., 1991). Their recognition as separate
Sotalia
species was based on
cranial geometric morphometric (Monteiro-Filho et al., 2002) and molecular studies
(Caballero, 2006; Caballero et al., 2007; Cunha et al., 2005)
To date, the scientific information collected about the species are related to reproduction,
growth, abundance and ecology as well as feeding habits, behavior as it relates to habitat use,
group size, and social structure (Best & Silva, 1984; Borobia & Barros, 1989; Silva & Best,
1994; Vidal et al., 1997; Ramos et al., 2000; Edwards & Schnell, 2001; Santos et al., 2000,
2001, 2002). But little has been accomplished in ethnobiological or ethnoecological
approaches.
Inclusion of ethnoecology studies facilitate our understanding of inter-relational
complexities between the human populations and the natural resources, with special attention
given to perception, knowledge and use (Begossi et al., 2002). However, the inadequacy of
that interface becomes clear when techniques that are adapted to the interdisciplinary
objectives of the researches are sought. Although the domain of basic techniques in
anthropological research, is dependent on interviews, and that for biological research, which
is dependent on the collection of specimens, are primordial, the growing use of approaches
and techniques of other disciplines has become even more essential (Marques, 2002).
M
ATERIALS AND
M
ETHODS
The research was developed in the Amazonian estuary (1°S - 4°40'N and 47° - 51°W;
Figure 1) from 1999 to 2001. The Amazonian estuary extends from the mouth of the
Amazon
River in the north and to the mouth of the Tocantins River in the south, linked through the
Breves Strait. Due to the enormous discharge of the two rivers the estuary is mainly fresh
water in the rainy period and slightly saline in the summer (Barthem & Schwassmann, 1994).
We utilized an ethnoecological approach experimental design, based on participatory
observation technique of fishermen during their routine labor work to meet the objective of
identifying, describing and quantifying the knowledge of human populations within the
Amazonian Estuary about the ecology and behavior of
Sotalia guianensis
. Semi-structured
interviews (n = 156) were applied, based on scientific information that contained the variables
to be studied: areas (A), degree of species occurrence (OD), habitat characteristics where the
species are found (H), group size (GS), frequency of calf observation (C), and behavior (B).
The variables OD and C were set up into three categories:
Common,
when fishermen
observe dolphins in almost all of their fishing routine;
Seasonal,
when fishermen observe
dolphins exclusively during the high tide and
Rare
when fishermen observe dolphins in other
periods of the year.
Search WWH ::
Custom Search