Biology Reference
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It's a K-selected species, with a slow growth rate, long life span, birth intervals of greater
than one year (Fernando et al., 2002) and have a lengthy pre-sexual maturity period (6-7
years).
Sotalia guianensis
seems to prefer shallow waters (Edwards & Schnell, 2001) and has
an Atlantic coastal distribution range that includes both Central and South America from
Honduras to southern Brazil (da Silva & Best, 1996; Simões-Lopes, 1988), but may be also
found hundreds of kilometers inland within the Orinoco River (Boher et al., 1995) and in the
Amazon Estuary. They have relatively high densities for small cetaceans at 0.9 to 8.6 animals
per squared kilometer (Vidal et al., 1997) and their group structure varies across its
geographical range from small groups of one to three individuals (Monteiro-Filho, 2000; Filla
& Monteiro-Filho, 2009) to extremely large groups in the hundreds (Lodi & Hetzel, 1998).
Within the Amazon Estuary alone they are estimated to be over 92,000 tucuxi dolphins (see
Beltran-Pedreros & Petrere's chapter). They seem to congregate in productive prey areas and
tend to avoid areas of heavy human activity where their habitat has been degraded (Azevedo
et al., 2007). Currently the IUCN classifies this species within the category of ―insufficient
data‖. The two largest threats for this species are the fishing industry and new dam
construction. Bycatch accounts for losses of over 4,000 tucuxi dolphins every year just within
the Amazon Estuary and seems to mostly affect solitary or small dolphin groups. All three of
Beltran-Pedreros et al.'s chapters (11, 12, & 13) in the current topic, discuss the bycatch
incidence problems associated with marine tucuxi. It is easy to find tucuxi skulls, dried eyes
and sexual organs (vaginas and penises) in some Amazon Estuary markets, such as the ver-O-
peso market at Belém (Pará state, Brazil). For example, one of the authors (Ruiz-García)
obtained more than 200 vaginas and penis samples in only a few hours (July 2005). One afro-
Brazilian ―witch‖ told him that she could obtain around 500 new vaginas and penises in one
or two days if he was interested in additional samples. The author did not accept the proposal.
These tissues are basically used for love charms and originate from tucuxi in bycatch.
Taxonomy:
of
Sotalia guianensis
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Suborder: Odontoceti ―toothed whales‖
Family: Delphinidae
Genus:
Sotalia
Species:
Sotalia guianensis
(van Beneden, 1864)
Sotalia fluviatilis
(Tucuxi Dolphin, Gray Dolphin, Bufeo-Negro, Bufeo-Gris)
Sotalia fluviatilis
(Figure 3), the only exclusively freshwater dolphinid in the world
(Cunha et al., 2005), has a structure similar to that of the coastal tucuxi dolphin (
Sotalia
guianensis
), but is smaller in overall body size (Barros, 1991; da Silva & Best, 1996) with the
maximum body length of
S. guianensis
being about 36% larger than that of
S. fluviatilis
(1.52
m). It wasn't until articles were published in 2002 (Monteiro-Filho et al.), 2005 (Cunha et.),
and 2007 (Caballero et al.) were the marine (
S. guianensis
) and riverine
sotalia
(
S. fluviatilis
)
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