Genetics of large pimelodidae catfishes: Contributions for ecology and conservation

Abstract

Pimelodidae catfishes, also identified as long-whiskered catfishes, are endemic of the Neotropical region, occurring in Central and South America hydrographic basins. This group of fishes presents a high diversity in body size that ranges from millimeters to more than 2 meters, and a wide variety of colors and skin pigmentations. Large pimelodids are high appreciated as food resources in fisheries and/or as aquaculture product throughout several countries of South America, such as some species of the genus Brachyplatystoma and Pseudoplatystoma. They realize long distance migratory movements during their reproductive period and play an important ecological role as carnivore predators. Several biological aspects are still scarce for most pimelodids, and the majority of species has no conservation status in the IUCN (International Union for Conservation of Nature). Anthropogenic interferences, as overfishing and dams that difficult their migratory reproduction has caused serious environmental impacts, placing at risk their wild populations. Genetics is an essential tool for conservation providing important data concerning to genetic diversity levels, species identification and inferences about ecology and population dynamics of several fish groups. Information about genetic diversity within populations may indicate recent negative effects of human interferences, as decreasing of allelic diversity or inbreeding. Genetic structure also may provide important data regarding to genetic differences between populations, as well as to contribute in studies of migration movements and homing behavior of these large catfishes. Furthermore, DNA markers have an extensive contribution to management and monitoring programs, as well as in the establishment of conservation areas or ESUs (Evolutionarily Significant Units). In this chapter, we addressed to some aspects of molecular DNA markers, their applications in populational, taxonomic and ecological genetic studies, and some actions for genetic conservation of large Pimelodidae species from South America.