Comunidade de algas perifíticas em tanques de cultivo de peixes em reservatório : o processo de colonização e sucessão utilizando substrato artificial.

Reservoirs are artificial ecosystems, built in the last few decades to serve various purposes, including aquaculture in net-cages. In reservoirs some studies are conducing with focus in colonization and succession of periphytic community, a complex community either firmly or lose attached in submersed substrata. In net-cages, there isn't any study to comprehend the structure and dynamic of periphytic community. The aim of this study was (a) to characterize the community of periphytic algae in net-cages for the cultivation of Nile Tilapia (Oreochromis niloticus) using three attributes of the community: richness, species composition and abundance; (b) to outline a sucessional model for this ecosystem and (c) provide a basis for further research. For this, slides of PET plastic were fixed in net-cages installed and utilized like artificial substratum. Qualitative analysis of the periphytic community revealed 168 taxa, distributed over 8 taxonomic classes. The class with the greatest number of species concentrated in the Zygnemaphyceae, with 35%, followed by Cyanophyceae (24%), Bacillariophyceae (21%) and Chlorophyceae (15%). Quantitative analysis of the periphytic algae community revealed six taxonomic classes, with a concentration of Bacillariophyceae. followed by Cyanophyceae and Chlorophyceae. In the initial phase of the sucessional process, unicellular algae predominated - principally diatoms - followed by filamentary forms. As complexity of the periphytic matrix increased, the filamentary algae fostered the development of unicellular epiphytes and weakly attached forms. This sucessional sequence was consistent with studies conducted in temperate zones. This study show that succession in periphytic algae communities was influenced by autogenic factors, as the variation observed in abiotic and climatological factors was very small. And is an important step for the valuation of communities in net-cages. This community can be considered a food source for stock fish, lowering feed costs, with benefits for both the producer and the environment. For this, however, further studies are necessary to test substrata and species adapted to using the periphytic community as a food resource.

Bibliographic Details

Main Author:	Siqueira, Natália Silveira
Format:	Thesis/Dissertation biblioteca
Language:	Portuguese
Published:	Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais. 2008
Subjects:	Ecology, Brazil, Ciências Ambientais, Brasil, Aquaculture, Periphytic algae, Management, Species richness, Reservoir, Net-cages, Artificial substratum, Reservatório, Tanques-rede, Composição específica, Aqüicultura, Algas perifíticas, Substrato artificial, Ecologia, Riqueza de espécies, Manejo, Specific composition,
Online Access:	http://hdl.handle.net/1834/10230
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