Resumo

BETANCUR GONZALEZ, Eliana Marcela; RUALES, Carlos Arturo David  e  GUTIERREZ, Luz Adriana. Periphyton diversity in a biofloc tilapia fish production system. Rev. Lasallista Investig. [online]. 2016, vol.13, n.2, pp.163-177. ISSN 1794-4449.  https://doi.org/10.22507/rli.v13n2a15.

Introduction. Periphyton is comprised of a complex community of aquatic organisms that get attached to underwater substrates, is a crucial component of the aquatic biotic communities and contributes to the understanding of these ecosystems. Some variations in the biofloc´s quality in raw protein and polyunsaturatted fatty acids levels terms can be conditioned mainly by periphyton´s structure. Objective. Determine the composition, abundance and diversity rates of periphyton in the different treatments for cultivating tilapia fish in biofloc. Materials and methods. Five samples of a tilapia fish culture in biofloc, associated to three treatments with their respective controls during a six months period, were taken. An inverted microscope with a camera was used to mount and count the sample (Sedgwick-Rafter camera). To determine and compose the assembly, taxonomic keys were used, and the species´ diversity, dominance, richness and equity rates were estimated. To calculate the diversity rate and the grouping scheme, the Biodiversity-Professional (Version 2) and PAST (Version 2.17c) softwares were used. Results. The assembly was comprised of 15 taxa. Eurotatoria was the most representative in taxa richness terms. The most abundant species was Crucigenia fenestrata. The sampling developed in different months of the year showed differences concerning the population density and the number of taxa found. The diversity rates oscilated between 0,3428 bel nat/ind and 0,7357 bel nat/ind. For the equity, values close or above 1 were found, and values under 0, 8 were also found as treatment 2 and the taxa richness showed a regularity between treatments. Conclusion. Periphytic microalgae represent one of the communities with the highest space variability in terms of biomass and composition, but none of the species maintain a considerable size of its population throughout the year, partly because of the disturbances in the treatments, which make them change their structure

Palavras-chave : Abundance; composition; bioindicators; active suspension.

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