Studies On The Plankton Of Aquaculture Ponds In Maolian Lake

The aquaculture field of Maolian Lake which located in Nanchang county is the first access to certified aquatic products pollution-free breeding base in Jiangxi Province, and pond culture is its main modes of supplying aquatic products. On the basis of aquaculture and the breeding environment harmonious sustainable development, the study were conducted in selected more typical experimental ponds from November 2006 to October 2007, the main elements are: the determination of the physical and chemical indicators in water; four typical culture types of phytoplankton community composition and seasonal variation analysis; the environment nutritional evaluation and analysis of breeding area. The main purpose of the study is that acquiring the plankton species composition structure and community structure in more typical breeding ponds and nutrition evaluation of water, which would be provide theoretical and practical basis for pollution-free aquaculture. Its major results of the study as follows:1. The main environment factors in aquaculture ponds: transparency, water temperature, pH, dissolved oxygen, total phosphorus, ammonia and nitrite were measured and analyzed in four more typical aquaculture ponds.2. 246 taxa of phytoplankton were identified, which belonged to 78 genera of 7 phyla. The year's average biomass was 2060.82×104ind / L. The number of species of Chlorophyta ranked the first, followed by Cyanophyta and Bacillariophyta, the biomass of Euglenophyta is also relatively large in some months. There were 41 dominant species which included Chlorella vulgaris, Scenedesmus spp., Ankistrodesmus angustus , Merismopedia enuissima, and so on. The biomass of phytoplankton is the best in summer and fewest in winter. The average concentration of the chlorophyll of a year is 12.33 mg/m3. The analysis of sampling on phytoplankton biodiversity indexes showed that the four sampling ponds have some differences.3. 60 species of zooplankton were identified, among which there were Rotifera 34 species, Copepoda 13 species, Cladocera 6 species, among which Rotifera has an dominance for 55.02%, especially Brachionus sp. offen appeared in trophic water. Brachionus angularis, Brachionus diversicornis, Brachionus calyciflorus, Trichocerca pusilla, Filinia longiseta and Polyarthra sp. were common species.4. Waters of aquaculture ponds in Maolian lake had reached eutrophication ecaluated by using physical and chemical indicators, and indicators of phytoplankton and corrected Carlson Tophic State indexes.5. When investigating waters of aquaculture ponds in Maolian Lake, we found that species and individual of plankton appeared miniaturization, predation of the fish and eutrophication may be the main reason.