Keywords: 
• film-lined pond /
• phytoplankton /
• zooplankton /
• spatial and temporal difference

Abstract: The species,quantity and spatial distribution of plankton during the shrimp culture cycle were observed in plastic-film-lined shrimp ponds from April to July 2012 at Haikou,Hainan,China to explore the spatial and temporal differences in plankton distribution in the shrimp ponds. During the shrimp culture there were 46 species under 8 phylums of phytoplankton in the shrimp ponds,including 15 species under the phylum chlorophyta; 9 under diatoms or cyanophyta; 2 under cryptophyta,euglenophyta,or dinoflagellates; 3 under xanthophyta,4 under chrysophyta. The dominant species were mostly under chlorophyta and bacillariophyta at the early stage of shrimp cutlure but mostly under cyanobacteria and chlorophyta at the mid and late stages. Their numbers of individuals of the phytoplankton were increased spirally and to the maximum at the mid stage of the culture,ranging from 3. 01 ×10⁷ to 1. 45 × 10⁸ cell / L. There were 28 species under 4 types of zooplankton: 16 species under protozoa,8 under rotatoria,2 under copepods and 2 species of larvae under other types of zooplankton. The dominant species were mostly under protozoa,rotatoria and copepods at the early stage of culture but mostly under protozoa and rotaria at the late stage of culture. The density of zooplankton increased gradually over time at the range of 0. 49 1. 2 × 10³cell·L^-1~10. 4 1. 2 × 10³ cell·L^-1. Spatial distribution of plankton had no significant difference in vertical distribution（ P ＞ 0. 05） but had significant differences in horizontal distribution（ P ＜0. 05） with the total number of individuals of plankton being in the order of D（ central area of the pond） ＞ C（ near the central area） ＞ B（ near the marginal area） ＞ A（ marginal area） area. The indexes of both diversity and dominance concentration of plankton were lower in the shrimp ponds,ranging between 1. 69 ~1. 76 and 0. 36 ~0. 44 for phytoplankton,respectively and 1. 39 ~1. 46 and 0. 3 ~0. 3 for zooplankton,respectively. Spatial and temporal differences in plankton distributionindirectly reflected the change of water quality in the film-lined shrimp ponds.