Abstract
The present study aimed at evaluating the composition, diversity and short-term temporal fluctuations of zooplankton communities in fish ponds. The study was carried out in two fish ponds, with 180 m(2) of water surface (6 x 30 m) each, located in the Aquiculture Centre of the Pindamonhangaba Fisheries Institute - São Paulo. The study was developed over eight weeks, from February 16 to April 6, 1998. The physical and chemical conditions of the water in the fish ponds were adequate for zooplankton development. The zooplanktonic community was characterised by high richness of species and a greater diversity was observed in the first fish pond, with a superior density of Rotifera. Temporal changes in zooplankton composition occurred in both ponds with Cladocera appearing in abundance later, in the fourth week, whereas copepods and rotifers were well represented since the beginning. Many species found are typical of fish ponds and are considered to constitute an excellent food source, showing high nutritional value for fish larvae, a good example being individuals from the Rotifera group and the micro-crustacean species Moina minuta and Thermocyclops decipiens.
Highlights
In recent years, freshwater aquaculture has undergone many advances due to efforts made to increase fish production (Sipaúba-Tavares et al, 1994)
The zooplankton community is usually dominated by the micro-zooplankton (Rotifera, Protozoa and copepod nauplii) (Sampaio et al, 2002)
Plankton production is a factor of great importance since it constitutes the most adequate food for the fish in their youngest phase, especially the rotifers and the cladocerans; the presence of these organisms in the environment may lead to better larval development (Feiden and Hayashi, 2005)
Summary
Freshwater aquaculture has undergone many advances due to efforts made to increase fish production (Sipaúba-Tavares et al, 1994). The diversity of zooplankton species in fish ponds is usually high, especially regarding rotifers, and many species can be used as water quality indicators (Macedo and Sipaúba-Tavares, 2005). Constant species (with more than 50% frequency of occurrence in the samples) amongst the cladocerans were Bosmina tubicen, Diaphanosoma spinulosum and Moina minuta; Thermocylops decipiens amongst the Copepods and Asplanchna sieboldi, Asplanchnopus sp., Brachionus calyciflorus, Brachionus caudatus, Conochilus sp., Keratella sp., Hexarthra intermedia and Sinantherina sp.
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