Evidence of lack of population substructuring in the Brazilian freshwater fish Prochilodus costatus

Curimbata-pioa (Prochilodus costatus Valenciennes, 1850) is an endemic species from the Sao Francisco River Basin with migratory habits, important ecological role in the ecosystem and relevant fishing importance. The present study aimed to assess the genetic variation in P. costatus in order to investigate its population genetic structure. Genetic variation was studied at three sites downstream the Tres Marias dam (Upper-middle Sao Francisco River, State of Minas Gerais) through six specific microsatellite loci. Fish from the three sites had quite similar genetic diversity levels and no genetic differentiation was detected, suggesting that P. costatus might represent a single reproductive unit in the studied area. Alternatively, the present study was not able to detect putative coexistent and comigrating populations along the main channel river. Our findings could be very helpful for the management and conservation of this fish.