RESUMEN
Events of catastrophic fish mortality in the lakes of the Amazonian floodplains are not uncommon. They are generally associated with thermal inversion of the water column, which is provoked by cold air masses that originate from the south of the continent. These events occur in the period of high water when the lakes are stratified. This paper reports an event of fish mortality that occurred during the low water season in a large floodplain system on the right-hand margin of the Amazon River. Information from seasoned fishers, who live in the same area where the event happened, and hydrological and satellite image analysis was used to identify the potential cause of fish mortality events. The amplitude of the flood pulse and the duration of extreme ebb showed to be the key factors responsible for the occurrence of events of fish mortality. These factors determine connectivity patterns between the floodplain lakes and the river channel, which are essential for maintaining water quality and the biota in the systems.
Asunto(s)
Peces , Lagos , Animales , Ríos , Biota , PercepciónRESUMEN
Events of catastrophic fish mortality in the lakes of the Amazonian floodplains are not uncommon. They are generally associated with thermal inversion of the water column, which is provoked by cold air masses that originate from the south of the continent. These events occur in the period of high water when the lakes are stratified. This paper reports an event of fish mortality that occurred during the low water season in a large floodplain system on the right-hand margin of the Amazon River. Information from seasoned fishers, who live in the same area where the event happened, and hydrological and satellite image analysis was used to identify the potential cause of fish mortality events. The amplitude of the flood pulse and the duration of extreme ebb showed to be the key factors responsible for the occurrence of events of fish mortality. These factors determine connectivity patterns between the floodplain lakes and the river channel, which are essential for maintaining water quality and the biota in the systems.
Eventos catastróficos de mortalidade de peixes em lagos de várzea da Amazônia não são incomuns, sendo, em geral, associados com a inversão térmica da coluna d'água, que é provocada por massas de ar frio que se originam no sul do continente. Esses eventos ocorrem no período de águas altas quando os lagos estão estratificados. Nesse artigo, relata-se um evento de mortalidade de peixes que ocorreu durante a estação de águas baixas em um grande sistema de várzea situado na margem direita do rio Amazonas. Usou-se o relato de pescadores residentes na área onde ocorreu o evento e com experiência na pesca, em conjunto com dados hidrológicos e imagens de satélite, para identificar potenciais causas do evento de mortalidade de peixes e propõe-se que a amplitude do pulso de inundação e a duração de secas extremas são os fatores chaves para a ocorrência dos eventos de mortalidade de peixes. Esses fatores determinam padrões de conectividade entre os lagos de várzea e o canal do rio, os quais são essenciais para a manutenção da qualidade da água e da biota nesses sistemas.