Fish and wildlife resources in the pantanal wetlands of Brazil and potential disturbances from the release of environmental contaminants

Abstract

Abstract-The Pantanal is one of the world's largest wetland ecosystems, encompassing 140,000 km 2 . The region is a breeding ground for waterfowl, and enormous rookeries of storks, herons, egrets, and ibises indicate a vast abundance of birds. The Pantanal is also one of the most important refuges for many of Brazil's threatened or endangered species, such as jaguars, giant anteaters, and swamp deer. The productive web of waters supports an important fishery industry. The Pantanal, with its extraordinary diversity and abundance of wildlife, is a threatened region. Deforestation, expanding agriculture, illegal hunting and fishing, unplanned tourism, and pollution with pesticides have caused a progressive deterioration of the natural environment, placing one of Brazil's most important ecosystems at risk. Gold mining is still common in the northern Pantanal. Along the Cuiabá river are 700 functional gold-mining dredges. In the town of Poconé, unregulated gold mines have also contaminated the area with mercury, which is used during the processing of gold. Approximately 50% of the fishes from the Cuiabá River and 35% from the Bento Gomes River have mercury levels higher than 0.5 g/g, which is beyond the international standard for contamination. Fishes from the Paraguay River have levels below 0.5. Birds like Phalacrocorax olivaceus, Aramus guarauna, and Rosthramus sociabilis were also contaminated. No research has been conducted on the fate of pesticides in the Pantanal. However, because of the huge demand for soybean plantations on the upland areas surrounding Pantanal, the application of toxic agricultural chemicals is very common.

Genetic Applications in the Conservation of Neotropical Freshwater Fish

“…Fish in the rivers of Madre de Dios city (Perú), affected by illegal mining, revealed that the species Calophysus macropterus, Pseudoplatystoma punctifer, P. fasciatum, H. malabaricus, Prochilodus nigricans, Hydrolycus pectoralis, Plagioscion squamosissimus and Zungaro zungaro showed high levels of mercury accumulation in tissues that exceeded the maximum limit permitted by the World Health Organisation (500 μgHg/kg) [81]. The same was found in the Upper Pantanal (Brazil), in the Poconé and Nossa Senhora do Livramento regions (Upper Paraguay River), where piscivorous or detritivorous species such as Pimelodus muculatus, P. fasciatum, P. lineatus, Salminus maxillosus, P. corruscans, Acestrorhynchus altus, Serrasalmus nattereri and H. malabaricus also had high levels of mercury [82,83]. Other metals that accumulate in fish organs are nickel and copper [80,84], causing significant damage to the fish species and its consumers.…”

Checklist da ictiofauna do Estado de Mato Grosso do Sul, Brasil

“…Outra ameaça à ictiofauna é a poluição das águas. A introdução de toxinas e outros contaminantes nos sistemas aquáticos do Mato Grosso do Sul é uma tendência indesejável para manutenção da qualidade dos hábitats, uma vez que afeta parcelas mais sensíveis da ictiofauna, bem como a qualidade dos recursos naturais, incluindo águas superficiais e subterrâneas (Alho & Vieira, 1997).…”

A conservation agenda for the Pantanal's biodiversity

“…The introduction of pollutants to ecosystems results in changes in an interrelated series of variables or processes that can affect the structure and function of the ecosystem in the short or long term. Alho and Vieira (1997) point out that unregulated gold mining has contaminated Pantanal habitats with mercury. Fish samples showed high percentages of contamination (Cuiaba and Bento Gomes rivers) with mercury beyond the levels allowed by international standards for contamination.…”