Resumo
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.
Conservar a variabilidade genética dos estoques de alevinos de peixes para suplementar populações naturais é uma prioridade. O objetivo deste estudo foi examinar a diversidade genética por meio dos marcadores de RAPD de amostras de peixes reprodutores de dourado do médio Paranapanema (população natural) e alevinos usados no programa de repovoamento da estação de aquicultura da UHE de Salto Grande. Foram analisados 19 primers de RAPD, que geraram 299 bandas, as quais foram utilizadas para as análises genéticas. A porcentagem de fragmentos polimórficos foi mais elevada na população natural do que nos estoques. A diversidade genética também foi mais baixa nos alevinos. Os resultados da Amova mostraram que a maior parte de variação genética interpopulacional está dentro dos estoques (83,9%) e não entre eles (16,1%). Foi observada uma diferenciação genética moderada (FST = 0.16). Esta diferenciação diminuiu quando os quatro estoques de alevinos eram misturados e analisados como uma única população (FST = 0.07). Em vez de liberar cada lote separadamente no ambiente, seria melhor misturar todos os indivíduos produzidos nos vários estoques de alevinos antes de liberá-los no rio. Desta maneira, a população reintroduzida terá uma estrutura genética mais perto da população natural.
Assuntos
Animais , Caraciformes/genética , Marcadores Genéticos , Técnica de Amplificação ao Acaso de DNA PolimórficoResumo
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.
The preservation of the genetic variability of hatchery stocks used to supplement naturalpopulations is a priority. Current study employed RAPD markers to examine the genetic diversity of douradosamples from the middle Paranapanema river and from the broodstock used in the stock enhancement programof the Aquaculture and Hydrobiology Station at the Salto Grande Hydroelectric Power Plant. Nineteen RAPDprimers were analyzed, which generated 299 bands and the latter were used for genetic analysis. The percentageof polymorphic fragments was higher in stock captured in the Paranapanema river than from fry stocks. Thegenetic diversity was lower in the broodstock than in natural population. Amova results showed that most interpopulationgenetic variation lay within stocks (83.9%) and not between them (16.1%). Moderate geneticdifferentiation (FST = 0.16) was reported. Nevertheless, differentiation decreased when the four fry stocks weremixed 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.
Resumo
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.(AU)
Conservar a variabilidade genética dos estoques de alevinos de peixes para suplementar populações naturais é uma prioridade. O objetivo deste estudo foi examinar a diversidade genética por meio dos marcadores de RAPD de amostras de peixes reprodutores de dourado do médio Paranapanema (população natural) e alevinos usados no programa de repovoamento da estação de aquicultura da UHE de Salto Grande. Foram analisados 19 primers de RAPD, que geraram 299 bandas, as quais foram utilizadas para as análises genéticas. A porcentagem de fragmentos polimórficos foi mais elevada na população natural do que nos estoques. A diversidade genética também foi mais baixa nos alevinos. Os resultados da Amova mostraram que a maior parte de variação genética interpopulacional está dentro dos estoques (83,9%) e não entre eles (16,1%). Foi observada uma diferenciação genética moderada (FST = 0.16). Esta diferenciação diminuiu quando os quatro estoques de alevinos eram misturados e analisados como uma única população (FST = 0.07). Em vez de liberar cada lote separadamente no ambiente, seria melhor misturar todos os indivíduos produzidos nos vários estoques de alevinos antes de liberá-los no rio. Desta maneira, a população reintroduzida terá uma estrutura genética mais perto da população natural.(AU)
Assuntos
Animais , Caraciformes/genética , Marcadores Genéticos , Técnica de Amplificação ao Acaso de DNA PolimórficoResumo
The aim of this study, utilizing RAPD techniques, was to determine the genetic variability of Salminus brasiliensis groups collected at passage ladders of the hydroelectric plants (HEP) Canoas I and Canoas II - Paranapanema River (Brazil), as well as to estimate the population structure through different parameters of genetic diversity. The data obtained allowed us to conclude that S. brasiliensis of the Canoas Complex has a moderate index of genetic variability (P > 42.00 percent) when compared to that of other migratory fish species. All genetic diversity analyses (distance = 0.015 and genetic identity = 0.985, F ST =0.018, AMOVA) were signs of low genetic differentiation, and they led to the clustering of S. brasiliensis from Canoas I and Canoas II. This suggests that the species is genetically structured as a single population. Some findings indicate that this population of S. brasiliensis comes from the Capivara Reservoir (Canoas I downstream), probably fed by the Tibagi and Cinzas Rivers. Literature data denote that after fish transposition by passage ladders of the Canoas Complex, the migratory species are not concluding the reproductive cycle. This mechanism, therefore, could be one more impact factor causing the depletion in downstream recruitment, which could in medium and long term be compromising the natural S. brasiliensis population in the middle Paranapanema River(AU)
O objetivo desse estudo, utilizando a técnica de RAPD, foi estimar a variabilidade genética de grupos de Salminus brasiliensis coletados nas escadas de transposição das hidroelétricas de Canoas I e Canoas II - rio Paranapanema (Brasil), bem como estimar a estrutura populacional através de diferentes parâmetros de diversidade genética. Os dados obtidos permitiram concluir que S. brasiliensis do Complexo Canoas tem um índice moderado de variabilidade genética (P > 42.00 por cento) quando comparado com valores de outras espécies de peixes migradoras. Todas as análises de diversidade genética (distância = 0,015 e identidade genética = 0,985, F ST =0,018, AMOVA) foram indicativas de baixa diferenciação genética, e conduziram ao agrupamento de S. brasiliensis proveniente das escadas de transposição de Canoas I e Canoas II, sugerindo que essa espécie está geneticamente estruturada como uma única população. Alguns dados indicam que essa população de S. brasiliensis é proveniente do Reservatório de Capivara (jusante de Canoas I), provavelmente mantida pelos rios Tibagi e das Cinzas. Dados da literatura indicam que após a transposição das escadas para peixes do Complexo Canoas, as espécies migradoras não estão concluindo o ciclo reprodutivo, esse mecanismo, portanto, pode ser mais um fator de impacto causando a depleção no recrutamento a jusante o que pode a médio e longo prazo comprometer a diversidade genética da população de S. brasiliensis no médio rio Paranapanema(AU)
Assuntos
Animais , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Variação Genética , Biodiversidade , Rios , Peixes/genéticaResumo
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.
The preservation of the genetic variability of hatchery stocks used to supplement naturalpopulations is a priority. Current study employed RAPD markers to examine the genetic diversity of douradosamples from the middle Paranapanema river and from the broodstock used in the stock enhancement programof the Aquaculture and Hydrobiology Station at the Salto Grande Hydroelectric Power Plant. Nineteen RAPDprimers were analyzed, which generated 299 bands and the latter were used for genetic analysis. The percentageof polymorphic fragments was higher in stock captured in the Paranapanema river than from fry stocks. Thegenetic diversity was lower in the broodstock than in natural population. Amova results showed that most interpopulationgenetic variation lay within stocks (83.9%) and not between them (16.1%). Moderate geneticdifferentiation (FST = 0.16) was reported. Nevertheless, differentiation decreased when the four fry stocks weremixed 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.