Abstract: To understand the community structure of planktonic ciliates and its relationship with environmental factors，planktonic ciliates were collected and identified in mariculture ponds of Litopenaeus vannamei and Tegillarca granosa. Meanwhile, cluster analysis and redundancy analysis were used to analyze the changes of community structure of ciliates and its relationship with physical and chemical factors of water. Results showed that 46 species of planktonic ciliates, mainly containing Oligotrichida(17 species), Hypotrichida(9 species), Haptorida(4 species), Scuticocliliatida(4 species), Cyrtophorida(3 species), were identified. From the point of abundance, after the first decline, total abundance showed a trend of rapid increase then decreased, and Oligochaeta was the dominant species, while other species shared a low abundance. Richness index(D) presented an upward trend and the tendency of evenness index(J) went with the change of diversity index(H′), which showed a small fluctuation during the breeding period. Changes of community structure of ciliates mainly embodied in Oligochaeta, containing Strobidinopsis, Strombidium and Tintinnopsis, and Haptorid including Cyclotrichium and Mesodinium. Major dominant species were positively correlated with DO(P<0.01), and can multiply in low content of NO-3, NO-2 and PO3-4. The results showed that ciliates were mainly Oligotrichida, while others were low and the relationship between community structure of ciliates and nutritions(DO, SD, NO-3, NO-2 and PO3-4) showed a good correlation in the pond of shrimp culture.

Key words: planktonic ciliates, Litopenaeus vannamei, Tegillarcagranosa, mariculture