Fish and aquatic habitat conservation in South America: a continental overview with emphasis on neotropical systems

Abstract

Fish conservation in South America is a pressing issue. The biodiversity of fishes, just as with all other groups of plants and animals, is far from fully known. Continuing habitat loss may result in biodiversity losses before full species diversity is known. In this review, the main river basins of South America (Magdalena, Orinoco, Amazon and Paraná-La Plata system), together with key aquatic habitats (mangrove-fringed estuaries of the tropical humid, tropical semi-arid and subtropical regions) are analysed in terms of their characteristics and main concerns. Habitat loss was the main concern identified for all South American ecosystems. It may be caused by damming of rivers, deforestation, water pollution, mining, poor agricultural practice or inadequate management practice. Habitat loss has a direct consequence, which is a decrease in the availability of living resources, a serious social and economic issue, especially for South American nations which are all developing countries. The introduction of exotic species and overfishing were also identified as widespread across the continent and its main freshwater, coastal and marine ecosystems. Finally, suggestions are made to find ways to overcome these problems. The main suggestion is a change of paradigm and a new design for conservation actions, starting with integrated research and aiming at the co-ordinated and harmonized management of the main transboundary waters of the continent. The actions would be focused on habitat conservation and social rescue of the less well-off populations of indigenous and non-indigenous peoples. Energy and freshwater demands will also have to be rescaled in order to control habitat loss.

Analysis of fish assemblages in sectors along a salinity gradient based on species, families and functional groups

“…Similarly, G. luteus was classified here as a marine straggler, while Barletta and Blaber (2007) considered it to be an estuarine species. These discrepancies highlight the need for more comprehensive information on the ecology and biology of the species inhabiting SW Atlantic estuaries (BARLETTA et al, 2010) to resolve such ambiguities.…”

Fishes of the Taquari-Antas river basin (Patos Lagoon basin), southern Brazil

“…However, river basins in Brazil are becoming increasingly transformed by human activities, particularly in the southeastern and southern regions, where land use change, pollution and damming for hydroelectricity are the main factors affecting fish conservation (Agostinho et al, 2008;Barletta et al, 2010). This continuous process of environmental change threatens the existence of fish species and their habitats, therefore conservation planning and prioritization require information on species composition and distribution in relatively large areas.…”

Genetic diversity of Arapaima gigas (Schinz, 1822) (Osteoglossiformes: Arapaimidae) in the Araguaia-Tocantins basin estimated by ISSR marker

“…Small populations tend to reduce genetic diversity due to high rates of inbreeding, inducing a high rate of homozygosity (Woodruff, 2001;Frankham et al, 2008). In this context, the loss of habitat has direct consequences in reducing population size, and this is more evident, especially for species of fish from inland waters (Barletta et al, 2010), since they tend to be isolated in drains, resulting in distinct populations (Allan & Flecker, 1993).…”