molecular markers, microsatellites, pirarucu, fish farming, PCR

Arapaima gigas, known in Brazil as pirarucu or pirosca, is the largest freshwater scale fish in South America, being found in floodplain areas of the Brazilian Amazon region and in other countries. Due to overfishing of its natural stocks, this fish was added to the list of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), but its demand continued to grow. Because it has appreciable commercial characteristics, such as tasty meat, good carcass yield, and relatively rapid growth of 10 kg in one year, it has become a species used for fish farming. Captive breeding generates profit for fish farmers and foreign exchange for the country, however the activity demands care, which if properly taken will prevent the genetic drift from taking unwanted paths, such as the bottleneck effect, which generates the loss of genetic diversity, making the flocks susceptible to parasites and consequently loss of productivity. Given this, this project aims to verify the genetic variability of captive pirarucu flocks in the state of Rondônia. The genetic diversity survey was carried out through the analysis of microsatellite nuclear genetic markers. This was done using PCR (polymerase chain reaction), a technique already widely used to verify genetic variability in natural stocks. Results obtained in this study indicate that the samples collected can be divided into three subpopulations: Extrema, Pimenta Bueno and Cacaulândia/Montenegro, as for allelic variability, only 1 of the 5 systems presented all alleles described in the literature, and one presented monomorphic in one of the subpopulations. Statistical analyses show moderate genetic variability between subpopulations and Hardy-Weinberg imbalance in 4 systems in 2 of the subpopulations.