Efeitos do cultivo de tilápias em tanques redes na estrutura da comunidade de Chironomidae.

• Autor(a) principal: Mangarotti, Danielle Paula de Oliveira
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/4808
• topic: Chironomidae de água doce; Poluição; Matéria orgânica; Oreochromis niloticus; Tilápia; Paranapanema, Rio, Bacia; Aquicultura; Chironomidae; Matéria orgânica; Brasil.; Aquaculture; Oreochromis niloticus; Chironomidae; Matter organic; Brazil.; Ciências Biológicas; Ecologia

World production of aquaculture (marine, estuarine and continental) grew 81.07% in the last 10 years, and although it is an old practice, studies evaluating the impact this activity on the aquatic communities are still few. In two rivers: Corvo and Guairacá, both Rosana reservoir tributary, where net cages were installed for cultivation of Oreochromis niloticus to evaluate the effects of aquaculture on the composition, distribution, similarity and the dominance of Chironomidae larvae. The samples were collected down with net cages, and 100 and 400 meters upstream and downstream of the net cages, using a modified handle type Petersen. The River Guairacá and the River Corvo, before the installation of the experiment, proved to be different abiotic environments, but during the experiment both rivers were exposed to a high load of ration and fish excreta, which caused the increase in concentrations of matter organic, and the sediment of rivers become more similar, contributing to the increase in the similarity of the community of both rivers. Other indication of changes in the structure of the community has been changes in the distribution of functional groups, with the increasing number of filtering-collectors and gathering-collectors. Probably, the food availability was responsible for the increase in the density of collectors. The community of Corvo River ocorred the biggest changes, as evidenced by the index of dominance. Clinotanypus sp. 1, which was dominant in the Corvo River disappeared after the installation of net cages, this may be an indication of a genus more sensitive to disturbances, while Coelotanypus for being tolerant to organic enrichment, managed to dominate in both environments. In Corvo river and the Guairacá River were not significant hanges in the variables limnological after the installation of tanks, networks, as was expected, however, the community has undergone biological changes in its structure and distribution in both rivers at all points of collection.