Genetic variability of Prochilodus lineatus (Characiformes, Prochilodontidae) in the upper Paraná river

Abstract

The genetic variability of the "curimba", Prochilodus lineatus, from three locations in the Paraná river basin, was investigated by starch gel electrophoresis. A total of 160 specimens were analyzed for 19 enzymes, 12 of which permitted successful interpretation of electrophoretic patterns. Eighteen loci were identified and six of them proved to be polymorphic (EST-1*, EST-2*, IDH-1*, PGM-1*, PGM-2*, LDH-2*). Mean heterozygosity was considered high (13%) by comparison with the literature. A low level of differentiation was found among subpopulations, with mean F ST = 0.018. Values of genetic distance and genetic identity suggest that, at least along this stretch of the river, P. lineatus comprises a single breed with high gene flow. This analysis has important implications for fishery management, aquaculture, and conservation of the stocks<br>A variabilidade genética das subpopulações de curimba, Prochilodus lineatus, coletadas em três localidades da bacia do rio Paraná, foi analisada pela eletroforese em gel de amido. Um total de 19 sistemas enzimáticos foram analisados, em 160 indivíduos, dos quais 12 apresentaram padrões eletroforéticos interpretáveis geneticamente. Dos 18 loci identificados, seis mostraram polimorfismo (EST-1*, EST-2*, IDH-1*, PGM-1*, PGM-2*, LDH-2*). A heterozigose média de 13% foi considerada alta quando comparada com os dados da literatura. Um baixo nível de diferenciação foi encontrado entre as subpopulações, com F ST = 0,018. Os valores de distância e identidade genética sugerem que, ao menos neste trecho da planície de inundação, P. lineatus representa uma única unidade reprodutiva com alto fluxo gênico. Esta análise tem importantes implicações para o manejo de pesca, piscicultura e conservação dos estoque

RAPD markers indicate the occurrence of structured populations in a migratory freshwater fish species

“…Previous enzyme electrophoresis, used to quantify the genetic variations of P. lineatus collected from three sites in the Paraná river basin, detected no genetic divergences among the three samplings, suggesting a unique genetic pool of P. lineatus spread along the studied area (Revaldaves et al, 1997).…”

Genetic variability in five species of Anostomidae (Ostariophysi - Characiformes)

“…Nevo (1978) estimated from data in the literature a mean P value of 15.2%, for 51 species of Teleostei. Studies carried out in fish species from Brazilian rivers show P values with a wide range of variation: Zawadzki (1996) found values from 11.45 to 19.23% in three species of the genus Hypostomus (Iguaçu River); Revaldaves et al (1997) observed 33.3% for Prochilodus lineatus (Paraná River) and Almeida and Sodré (1998) observed values from 6.67 to 20% in three Pimelodidae species (Tibagi River). Ward et al (1992) estimated an He value of 0.051 for about 150 marine and fresh water fish species.…”

Allozyme variation among three populations of the armored catfish Hypostomus regani (Ihering, 1905) (Siluriformes, Loricariidae) from the Paraná and Paraguay river basins, Brazil

“…Marine fish populations have fewer barriers to gene flow and usually show less genetic differentiation than freshwater fishes (Gyllensten, 1985;Ward et al, 1994). Some migratory freshwater fish species such as P. lineatus (Revaldaves et al, 1997;Sivasundar et al, 2001) and P. corruscans (Sekine et al, 2002) show low genetic differentiation while poorly migratory or resident species such as H. malabaricus show high genetic differentiation (Dergam et al, 1998).…”

“…The wide geographical range of H. regani not only contrasts with the narrow distribution of most Hypostomus species but can also raise doubts about the conspecificity of H. regani populations. Studies of the genetic population structure of Neotropical fish have mainly focused on known migratory species such as Prochilodus lineatus (Characiformes, Prochilodontidae) (Revaldaves et al, 1997) and Pseudoplatystoma corruscans (Siluriformes, Pimelodidae) (Sekine et al, 2002), with studies on nonmigratory fish having been restricted to Hoplias malabaricus (Characiformes, Erythrinidae) (Dergam et al, 1998;Peres et al, 2002). We have no data about migratory behavior of H. regani, whether it is resident, short, medium or long distance migratory.…”