TITLE:
Eutrophication Indexes Used as Fish Production Parameters in the Itaipu Reservoir (Brazil)
AUTHORS:
Rinaldo Antonio Ribeiro Filho, Julia Myriam de Almeida Pereira, Miguel Petrere Júnior, Simone Frederigi Benassi
KEYWORDS:
Trophic Cascade Reservoir; Limnology; Biotic Community; Fish Yield
JOURNAL NAME:
Journal of Environmental Protection,
Vol.4 No.7A,
July
24,
2013
ABSTRACT: The knowledge of
liminology can be applied in studies of trophic state indexes and morfoedaphic
indexes as factors for determining the inference fish production in reservoirs.
This work is based on the hypothesis of the trophic cascade relations,
particularly related to bottom-up and top-down effect in Itaipu Reservoir
(Brazil). Using the data available by Itaipu, from 1999 to 2004, analyzes of
multiple regressions were accomplished to determine the relationships of the
dependent and independent variables. We applied the trophic state indices (TSI)
based on readings Secchi disk, total phosphorus and chlorophyll-a density for obtaining TSI medium.
Morfoedaphic index was calculated based on the reading of the concentration of
dissolved solids and the inference of fishing yield, from this index. The
average results of the trophic state indices indicate an oligotrophic status
for the entire reservoir as well as for the riverine, transition and lacustrine
zones separately. The fish was yieldn Estimated by the relation with
cyanobacteria concentration, and this was the best variable que explained this
prediction. The use of the morfoedaphic index (MEI), with the recorded catch
data, predictive models can generate que estimate the fishing yield in the
Itaipu Reservoir. The relations of MEI with chlorophyll-a and water
transparency que Indicate this index may be a good predicting factor for future
fish captures.