This work aimed at to evaluate during a cycle of cultivation of Litopenaeus vannamei
with biweekly periodicity from 20/09/08 to 05/12/08 the community planktonic and the
abiotic parameters in two stations inside of a pond in the municipal district of Curuça,
State of Pará. They were measured transparency, pH, dissolved oxygen, salinity and
temperature, being the last four registered in the surface and close to the bottom and
accomplished collections for the study of the microfitoplankton, zooplankton and
chlorophyll “a”. The temperature varied from 31,5ºC to 35ºC. The dissolved oxygen
varied from 4,2 mg/l to 15,5 mg/l. The pH stayed lightly alkaline, between 8,1 and 9,4.
To smallest salinity it was 26,9 and the largest, 30 ppm. The transparency decreased of
55 cm to 17 cm. Chlorophyll a had a minimum of 2,33mg/m3 and a maximum of 471,34
mg/m3. They were identified 95 taxa and Bacillariophyta was the most important group,
being Navicula, Pleurosigma and Nitzschia the main ones responsible for her
dominance. The largest density registered for the microfitoplankton was of 104.400 org/l
in the beginning of the cultivation (20/09) and to smallest it was 3.600 org/l in the last
collection (05/12). The diversity average for the fitoplakcton in the Station 01 was 1,49
bits/ind and in the Station 02, 1,43 bits/ind. They were identified 34 taxa zooplanktonic,
being Copepoda the most important group and Acartia lilljeborgi, Euterpina acutifrons,
Oithona hebes, Oithona oswaldocruzzi and Parvocalanus crassirostris the main ones
responsible for her dominance. The largest density registered for the zooplâncton was of
162.000 org/m3 in the beginning of the cultivation (20/09) and to smallest it was 375
org/m3 in day 05/11. The diversity was also low tends averages of 1,34 bits/ind and 1,10
bits/ind in the stations 01 and 02, respectively. Enter the main conclusions: the
microfitoplanktonic community was dominated by the diatom, being the main ones
responsible for her dominance: Pleurosigma, Nitzschia and Navicula and the division
Bacillariophyta was the most important group so much in wealth terms as of density; the
class dinophyceae revealed to be better adapted in clearer waters; the copepods were
dominant, being Acartia lilljeborgi, Oithona hebes, Oithona oswaldocruzzi, Parvocalanus
crassirostris and Euterpina acutifrons the species that more they contributed to this
dominance; Chlorophyll “a” answered to the largest ration contributions during the
cultivation, increasing with the time; the physio-chemical variables that suffered
influence of the cultivation, varying significantly along the time was: pH, dissolved
oxygen and transparency and the investigated pond was considered homogeneous
evaluating her depth and area.
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