Genetic monitoring by rapd markers for repopulation programs of Salminus brasiliensis (Pisces, Characiformes)

Fernanda Simões De Almeida,Carla Martins Lopes,Leda Maria Koelblinger Sodré,Mário Luís Orsi,Rodolfo Nardez Sirol

doi:10.4025/actascianimsci.v35i2.15904

Abstract

The preservation of the genetic variability of hatchery stocks used to supplement natural populations is a priority. Current study employed RAPD markers to examine the genetic diversity of dourado samples from the middle Paranapanema river and from the broodstock used in the stock enhancement program of the Aquaculture and Hydrobiology Station at the Salto Grande Hydroelectric Power Plant. Nineteen RAPD primers were analyzed, which generated 299 bands and the latter were used for genetic analysis. The percentage of polymorphic fragments was higher in stock captured in the Paranapanema river than from fry stocks. The genetic diversity was lower in the broodstock than in natural population. Amova results showed that most inter-population genetic variation lay within stocks (83.9%) and not between them (16.1%). Moderate genetic differentiation (FST = 0.16) was reported. Nevertheless, differentiation decreased when the four fry stocks were mixed and analyzed as a single population (FST = 0.07). Instead of releasing each lot separately into the water, mixing specimens produced in the various fry stocks before releasing them in the river would be more feasible. The restocked population will have a genetic structure closer to natural populations.

Highlights

The construction of dams requires the adoption of procedures to reduce the impact on fish populations during and after reservoir formation
Specimens of S. brasiliensis were collected in the fish ladders of Canoas I (50o 31’W and 22o 56’S) and Canoas II (50o 15’W and 22o 56’S) hydroelectric plants (HEPs), in the Middle Paranapanema river, with reservations as to the spawning period from September to March (Figure 1)
The determination of the genetic variability of the matrix group used for repopulation programs is a fundamental tool for the genetic conservation of a species (SIROL; BRITTO, 2005; POVH et al, 2008)

Summary

Introduction

The construction of dams requires the adoption of procedures to reduce the impact on fish populations during and after reservoir formation. Genetic variability within and among the different stocks was evaluated by RAPD to highlight the tasks necessary in the future for better hatchery management and species conservation. In spite of the reduction in genetic variability observed in_fry stocks, rates were quite similar to the mean of ⎯ P (43.49%) reported by Lopes et al (2007) for S. brasiliensis.

Results

Conclusion