Biology Reference
In-Depth Information
the Veda General Indefinida (D.S. 25458), enacted in July of 1999, which is a general decree
that prohibits the harassment, capture, harvest, and training of wild animals and their
derivatives. Debate exits over the effectiveness of this law, but it continues to be in effect in
the absence of more stringent or specific laws (Aliaga-Rossel, 2002).
The IUCN has categorized the bufeo (
Inia geoffrensis
) as a Data Deficient (IUCN, 2009)
and it is listed under CITES Appendix II. In the 2008 workshop for the ―Red List of
Vertebrates of Bolivia‖,
Inia boliviensis
was categorized as
Vulnerable
, but there are no direct
actions or conservation plans from the government. It is important to highlight that the Beni
Department declared the bufeo as a ―Natural Heritage‖ of the Beni area (Law evicted on
March 2008) (Aliaga-Rossel, 2009).
Although much of the area of distribution of
Inia
is unprotected, River Dolphins do occur
in five protected areas: Noel Kempff Mercado National Park, Indigenous territory and
National Park Isiboro-Securé, Beni Biological Biosphere Reserve, Itenez Protected Area and
the Elsner Espiritu Private Wildlife Refuge. However even in these areas water quality can be
reduced because of contamination or other factors, from outside the area.
Genetic studies by Ruiz-García et al. (2008a), indicated that the bufeo population (
Inia
boliviensis
) has the lowest genetic richness compared to the other populations, indicating that
in some lagoons there are no genetic flows and that there is a very limited inter-connection
among populations. Consequently the species seems to be vulnerable to any threat that may
affect it.
The direct threats to the bufeo population are identified as habitat degradation,
contaminate loads, hunting, over-fishing, navigation by aquatic vessels, and dams. Each of
these factors is discussed next.
Habitat Degradation, Decreased Water Quality and Contaminants
The main threat is the deterioration and degradation of the aquatic habitat due to high
phosphorus loads and influxes of toxins such as heavy metals, DDT, and chlorine compounds
(Maurice-Bourgoin, 1999; Reeves & Kasuya, 2000; Reeves
et al.,
2003). That comes from
pesticides, and agricultural activities. Heavy metals (mercury, arsenic, and lead) originate
from gold mine areas, and are used to separate gold from other elements. Later these
contaminate bi-products are dumped into rivers where they can magnify in the food chain
(Best & Da Silva, 1993; Maurice-Bourgoin et al., 1999).
There is uncontrolled gold exploitation along the Beni River, where there are no controls
or specific laws regarding the contaminants that are dumped into the water. Studies carried on
the Beni River and among human populations along the upper Madeira River in Brazil have
shown that the mercury level is above regulatory limits (Barbosa et al., 1998; Dorea et al.,
1998; Maurice-Bourgoin et al., 1999, 2000; Hacon et al., 2000; Dolbec et al., 2001). These
authors indicate that these elevated contamination concentrations are affecting not only the
people directly engaged in or near mining activities, but also affecting populations located
150 km downriver, where mercury has been found in the hair of people that have a high
consumption of fish. Mercury is associated with lesions in the neurological system, motor
dysfunction and ocular problems. Studies show the direct effects of the bio-accumulation of
contaminants in fish and humans (Hacon et al., 2000; Senthilkumar et al., 1999). This clearly
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