Genetic diversity and population structure of bocachico Prochilodus magdalenae (Pisces, Prochilodontidae) in the Magdalena River basin and its tributaries, Colombia

Abstract

Prochilodus magdalenae is an endemic freshwater fish that occurs in the Magdalena, Sinú and Atrato hydrographic basins. It has an important economic role and is a food resource for the artisanal fishing communities. Its socioeconomic importance contrasts with the current status of its fisheries, where stocks are being depleted. Considering its importance and lack of information on its genetic structure, we used seven microsatellite markers to assess the genetic structure of wild populations of P. magdalenae. The genetic diversity was assessed and the population genetic structure was estimated through Fst, analysis of molecular variance and Bayesian analysis. A total of 290 alleles were found in all loci throughout all population. The high polymorphism contrasts with the levels of observed heterozygosity (Ho = 0.276), which are the lowest values recorded for the family. We found three populations of bocachico coexisting throughout the studied system, contradicting the hypothesis that freshwater migratory fish form panmictic populations. These results on the genetic structure of P. magdalenae constitute tools for a better understanding of the behavior and biology of this species, contributing to fish management and conservation programs.

Genetic structure and diversity of migratory freshwater fish in a fragmented Neotropical river system

“…The same pattern was obtained for other species of this genus in the Magdalenae River for P. magdalenae (H E = 0.877)(Berdugo and Barandica 2014) and in the São Francisco River for P. argenteus (H E = 0.605-0.785)(Barbosa et al 2006;Hatanaka et al 2006;Barbosa et al 2008;Sanches et al 2012) and P. costatus (0.448-0.660) (Carvalho-Costa et al…”

“…In addition, large effective population sizes also increase the rate of allelic Rev Fish Biol Fisheries recombination (Agostinho et al 2003;Ferreira et al 2015). Prochilodus lineatus samples analyzed in this study showed high genetic diversity levels comparable to other migratory freshwater fish (Matsumoto and Hilsdorf 2009;Santos et al 2007;Berdugo and Barandica 2014). Microsatellite analysis suggested relatively high levels of genetic diversity (H E = 0.803-0.874 and N A = 11.42-20.42 alleles per locus), higher than the average estimated for freshwater fish (H E = 0.54 and N A = 9.1 alleles per locus) (Dewoody and Avise 2000), and similar to those previously reported for other Neotropical migratory fish species (Calcagnotto et al 2001;Barroso et al 2003Barroso et al , 2005Morelli et al 2007;Matsumoto and Hilsdorf 2009).…”

“…Migratory fish populations, including several species of Neotropical freshwater fish, have been reported to exhibit high levels of genetic diversity (Matsumoto and Hilsdorf 2009;Santos et al 2007;Rueda et al 2011;Berdugo and Barandica 2014). The migratory movements of these species enable large populations to be maintained (high effective population sizes), minimizing the loss of genetic diversity through genetic drift ).…”

“…Thus, the results obtained could have influences from the high migration capacity of P. lineatus and the connectivity maintained by fish passages. In different river basins, low levels of population genetic differentiation have been reported for other species that, like P. lineatus, also exhibit high migration capabilities ([1000 km) Lopes et al 2007;Santos et al 2007;Ribolli et al 2012;Berdugo and Barandica 2014). Migratory movements help maintain high gene flow, which in turn results in less pronounced population structure (Freeland 2005;Adamson et al 2012).…”

“…Obviously, the presence of obstacles limiting or preventing gene flow can cause genetic differentiations, such as those obtained for P. lineatus (Garcez et al 2011) and P. costatus (Barroca et al 2012) populations separated by dams in Neotropical River basins. However, even where there are no obstacles, patterns contrasting to a panmixia scenario have been shown in Prochilodus species, including the coexistence of different reproductive units along the same river (Hatanaka and Galetti Jr. 2003;Hatanaka et al 2006;Berdugo and Barandica 2014) and temporal structuring among different stocks in the same drainage location (Rueda et al 2013;Braga-Silva and Galetti Jr. 2016). Studies also suggest that homing behaviors (breeding site fidelity) could explain patterns in population structuring observed for some species of this genus (Hatanaka and Galetti Jr. 2003;Hatanaka et al 2006;Sanches et al 2012).…”