Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.3/255
Título: Effects of fish removal in the Furnas Lake, Azores
Autor: Bio, Ana
Couto, A.
Costa, R.
Prestes, Afonso L.
Vieira, N.
Valente, A.
Azevedo, José M. N.
Palavras-chave: Lagoa das Furnas
Qualidade da Água
Açores
Furnas Lake
Water Quality
Azores
Cyprinus carpio
Rutilus rutilus
Data: 2008
Editora: Universidade dos Açores
Citação: "ARQUIPÉLAGO. Ciências Biológicas e Marinhas". ISSN 0873-4704. Nº 25 (2008): 77-87
Relatório da Série N.º: Ciências Biológicas e Marinhas = Life and Marine Sciences;25
Resumo: The Furnas Lake is a small volcanic, monomitic and increasingly eutrophised water body. Next to agricultural nutrient inputs, high densities of herbivorous fish are thought to contribute to high levels of turbidity in the lake, through zooplankton consumption and re-suspension of the nutrients accumulated in the sediment. According to the alternative state hypothesis a shift from turbid to clear water conditions is favoured by reduction of nutrient concentrations, increased light availability and reduction of planktivorous and benthos-feeding fish stock. To improve water quality in the Furnas Lake, a substantial part of the bottom-feeding fish population (62% of the estimated common carp population, Cyprinus carpio, and 5% of the estimated roach population, Rutilus rutilus) was removed. Effects of fish removal on turbidity and associated trophic state were analysed next to postmanipulation chlorophyll a concentration, zooplankton and macrophytes densities. Results suggest that fish removal was not enough to change lake conditions towards a lasting clear state dominated by macrophytes. Excessive nutrient load, in water and sediments, nutrient input from the lake basin and fish recruitment causing enhanced zooplankton grazing are appointed causes. Any further biomanipulation efforts should be associated to nutrient reduction; and continued monitoring of water quality, fish stock, macrophytes and zooplankton is needed.
URI: http://hdl.handle.net/10400.3/255
ISSN: 0873-4704
Aparece nas colecções:ARQ - LMS - Número 25

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