Contribution of conservation genetics in assessing neotropical freshwater fish biodiversity

Abstract

Human activities have a considerable impact on hydrographic systems and fish fauna. The present review on conservation genetics of neotropical freshwater fish reveals that DNA analyses have been promoting increased knowledge on the genetic structure of fish species and their response to environmental changes. This knowledge is fundamental to the management of wild fish populations and the establishment of Evolutionary Significant Units capable of conserving genetic integrity. While population structuring can occur even in long-distance migratory fish, isolated populations can show reduced genetic variation and be at greater risk of extinction. Phylogeography and phylogeny have been powerful tools in understanding the evolution of fish populations, species and communities in distinct neotropic environments. Captive fish can be used to introduce new individuals and genes into the wild and their benefits and disadvantages can be monitored through genetic analysis. Understanding how fish biodiversity in neotropical freshwaters is generated and maintained is highly important, as these habitats are transformed by human development and fish communities are increasingly exploited as food sources to sustain a growing human population.Keywords: molecular genetics, fish population, biology conservation. Contribuição da Genética da Conservação para o conhecimento da biodiversidade dos peixes de água doce neotropicais ResumoAtividades humanas têm um grande impacto sobre os sistemas hidrográficos e a fauna de peixes. A presente revisão em genética da conservação dos peixes de água doce neotropicais revela que as análises de DNA têm promovido um crescimento no conhecimento da estrutura genética das espécies e suas respostas às alterações ambientais. Este conhecimento é fundamental para o manejo das populações de peixes nativos e para o estabelecimento de Unidades Evolutivas Significantes capazes de conservar a integridade genética dessas populações. Enquanto o fenômeno de estruturação de populações pode ocorrer mesmo em peixes migradores de longas distâncias, populações isoladas podem mostrar reduzida variação genética e apresentar grande risco de extinção. Em adição, a filogeografia e a filogenia têm dado importantes contribuições para o entendimento da evolução das populações, espécies e comunidades de peixes em distintos ambientes neotropicais. Populações de cativeiro podem ser utilizadas como fonte de introdução de novos indivíduos e genes no ambiente natural e seus benefícios e desvantagens podem ser monitorados por meio de análises genéticas. É altamente importante, portanto, entender como é gerada e mantida a biodiversidade de peixes de água doce neotropicais, uma vez que os habitats são transformados pelo desenvolvimento humano e as comunidades de peixes têm sido intensamente exploradas como alimento de sustentação desse crescimento das populações humanas.Palavras-chave: genética molecular, populações de peixes, conservação biológica.

Genetic analysis of five sedentary fish species in middle Laranjinha River (upper Paraná River basin): A case study

“…F statistics (Wright, 1978) or their analogs are measurements of the hierarchical levels of structure within and between populations (Piorski et al, 2008;Oliveira et al, 2009). In the present study, relatively low levels of genetic structure, i.e., F ST /ϕ ST values smaller than 0.05 (Wright, 1978;Excoffier et al, 1992), were found in four species but not S. insculpta (Table 2).…”

“…RAPD markers have been used for analysis of genetic diversity and structure in freshwater fish species (Piorski et al, 2008). Despite the limitations of the technique, prudent application of these markers can provide equivalent results and interpretations to those derived from codominant marker analysis (Ramos et al, 2008(Ramos et al, , 2012Phong et al, 2011).…”

“…Genetic diversity studies in neotropical ichthyofauna have focused on species with a long history of reproductive displacement (Piorski et al, 2008;Oliveira et al, 2009). The effects on these species are often related to the immediate impacts of the construction of dams, which often affect migration routes and, therefore, gene flow within and between populations.…”

“…These changes influence the reproduction, distribution, and vulnerability of populations to stochastic processes related to loss of genetic diversity (Slatkin, 1985;Piorski et al, 2008;Oliveira et al, 2009). The upper Paraná River basin is one of the most studied watersheds in South America.…”

“…Furthermore, such information can be very helpful in understanding the effects of anthropogenic activities, such as dams, on the fish populations throughout the river basin. In the last decade, use of PCR-RAPD (random amplified polymorphic DNA) markers has been widely adopted to study genetic diversity and structure in neotropical fish populations in South America (Piorski et al, 2008), producing results that are comparable with those from other markers (Ramos et al, 2008;Muneer et al, 2009;Phong et al, 2011).…”