A estratégia reprodutiva dos peixes migradores frente às escadas do Complexo Canoas (Rio Paranapanema, Bacia do Alto Paraná)
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Data
2009-02-19
Autores
Britto, Sandro Geraldo de Castro [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A construção das barragens e formação de lagos artificiais acarreta uma série de impactos com danos sobre a fauna e flora, e em especial, sobre as comunidades de peixes. Decorrente da legislação ambiental existe a polêmica exigência de construção de meios para transposição de peixes (escadas e outros artefatos) nestas barragens. Teoricamente, esta inclusão visa à manutenção da diversidade ou a conservação das espécies com estratégia reprodutiva envolvendo a migração de longas distâncias, as quais são efetivamente impactadas pelos barramentos. Esses mecanismos são concebidos para fornecer condições ecológicas favoráveis à manutenção de populações viáveis, possibilitando rotas migratórias alternativas. Nesse sentido, foram construídas escadas para peixes nas usinas hidrelétricas Canoas I e Canoas II, situadas no trecho médio-inferior do Rio Paranapanema, Bacia do Alto Paraná. Com o objetivo de avaliar a estratégia reprodutiva de peixes migradores frente à eficiência destas escadas na transposição de peixes, foram realizadas amostragens, durante cinco períodos reprodutivos, entre os anos de 2001 e 2006. Os estudos implementados abordaram as populações de peixes que fizeram uso destes mecanismos de transposição, com enfoque quali-quantitativo sobre as espécies migradoras de longa distância. Além disso, da avaliação do deslocamento dos peixes rio acima após essas transposições, utilizando a técnica de marcação e recaptura e a verificação do sucesso reprodutivo das espécies migradoras registradas nas escadas. Para tanto, foram realizadas coletas de ovos, larvas e juvenis de peixes, nos reservatórios a montante. No período de estudo verificou-se uma redução do número de espécies, inclusive das migradoras de longa distância, e também uma acentuada redução quantitativa na captura, indicando a ocorrência de algum...
The construction of dams and creation of artificial lakes leads a series of impacts with damages on the fauna and flora, in special on the fish communities. Due environmental laws, have the controversy requirement of the construction of way for fish transposition (the fish ladders or others artifacts). Theoretically, this inclusion is aimed at the maintenance of biodiversity or the species conservation with reproductive strategy involving long distances migration, which is more effective impacted by dams. These mechanisms are designed as a way to create favorable ecological conditions to the maintenance of viable populations, enabling alternative migration routes. In that sense, has been built fish ladders in Canoas I and II Canoas dams, located in the mid-lower portion of the Paranapanema River, the Alto Parana Basin. With the objective to assess the reproductive strategy of migratory fish front the fish ladders efficiency in the transposition, samples were taken for five reproductive periods, between the years 2001 and 2006. The studies were implemented about the fish populations that have made use of these mechanisms, with qualitative-quantitative focus on the long-distance migratory species. Moreover, assessing the displacement of fish upstream after transpositions, using the catch, mark and recapture techniques and check the reproductive success of migratory species recorded in fish ladders. For this, were performed collections of eggs, larval and juvenile fish in reservoirs upstream. In studied period, there was a reduction in the number of species, including the longdistance migratory, with a marked quantitative reduction of catch, indicating some impact on the populations of the downstream. Specially, the data of recaptures demonstrated that of the fish ladders are, generally, unidirectional upward, with barely any downward transposition. Also, after going up the fish ladders... (Complete abstract click electronic access below)
The construction of dams and creation of artificial lakes leads a series of impacts with damages on the fauna and flora, in special on the fish communities. Due environmental laws, have the controversy requirement of the construction of way for fish transposition (the fish ladders or others artifacts). Theoretically, this inclusion is aimed at the maintenance of biodiversity or the species conservation with reproductive strategy involving long distances migration, which is more effective impacted by dams. These mechanisms are designed as a way to create favorable ecological conditions to the maintenance of viable populations, enabling alternative migration routes. In that sense, has been built fish ladders in Canoas I and II Canoas dams, located in the mid-lower portion of the Paranapanema River, the Alto Parana Basin. With the objective to assess the reproductive strategy of migratory fish front the fish ladders efficiency in the transposition, samples were taken for five reproductive periods, between the years 2001 and 2006. The studies were implemented about the fish populations that have made use of these mechanisms, with qualitative-quantitative focus on the long-distance migratory species. Moreover, assessing the displacement of fish upstream after transpositions, using the catch, mark and recapture techniques and check the reproductive success of migratory species recorded in fish ladders. For this, were performed collections of eggs, larval and juvenile fish in reservoirs upstream. In studied period, there was a reduction in the number of species, including the longdistance migratory, with a marked quantitative reduction of catch, indicating some impact on the populations of the downstream. Specially, the data of recaptures demonstrated that of the fish ladders are, generally, unidirectional upward, with barely any downward transposition. Also, after going up the fish ladders... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Peixe - Reprodução - Paranapanema, Rio (PR), Zoologia, Fish ladders, Reservois
Como citar
BRITTO, Sandro Geraldo de Castro. A estratégia reprodutiva dos peixes migradores frente às escadas do Complexo Canoas (Rio Paranapanema, Bacia do Alto Paraná). 2009. 141 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2009.