凡纳滨对虾常见养殖模式下养殖后期浮游植物及理化因子的变化

对凡纳滨对虾几种常见养殖模式后期的浮游植物及理化因子进行了调查研究,结果表明,浮游植物的群落特征因养殖模式、养殖时间、不同的环境条件等原因变化很大,其群落组成由最少的11种到最多的28种不等;其优势种与次优势种中以蓝藻门、绿藻门、硅藻门为主,甲藻门、裸藻门偶有出现,主要优势种有小环藻、波吉卵囊藻、中肋骨条藻、颤藻、林氏藻、裸甲藻、胶球藻、小席藻、腔球藻等,浮游植物群落的生物多样性由高至低依次为高位池分级精养模式、海水土池粗养模式、低盐度养殖模式、咸淡水半精养模式、工厂化集约养殖模式、高位池集约养殖模式,多样性指数与优势度呈显著的负相关,而与均匀度呈显著的正相关。细胞密度485.9×104~35459.8×104L-1,在高密度精养模式中,浮游植物的密度与无机氮、硫化氢含量的变化在早期呈负相关,在后期则几乎同步增长;在低密度养殖模式中,浮游植物的密度与无机氮、硫化氢含量的变化始终呈负相关。各养殖模式pH值的变化与浮游植物的密度呈正相关。综合分析表明,高密度养殖宜采用高位池分级精养模式,低密度养殖宜采用海水土池粗养模式。

Change of Phytoplankton and Physicochemical Factors in Ponds of Shrimp Penaeus vannamei with Different Cultural Patterns During Late Period

The species of phytoplankton and physicochemical factors were investigated in shrimp Penaeus vannamei ponds with different cultural patterns during late period. The results showed that the character ofphytoplankton community changed sharply with different cultural pattern, period and environment conditions. The community consisted of 11 to 28 species. Most dominant species and subdominant ones belongs to the phylum of Cyanophyta, Chlorophyta and Bacillariophyta, at the same time, some dominant or subdominant species occured in Pyrrophyta and Euglenophyta occasionally. The main dominant species were Cyclotella sp., Oocystis borgei, Skeletonema costatum, Oscillatoria sp., Lyngbya sp., Cymnodinium sp., Gloeocapsa limnetica, Phormidum tenue, and Coelosphaerium sp. and so on, in which Cyclotella sp, Cryptomonas sp. and Lyngbya sp. were wide-distributing species with strong adaptation and resistance of pollution. The diversity of the phytoplankton was more abundant in the high-order pool hierarchical punctilous animal husbandry method, followed by the culture in sea-water soil pool, the pure fresh water cultivates, salty fresh water half punctilous animal husbandry cultivate method, the mode factory intensively, and the high-order pool intensifies and cultivates in each cultivation method in order. The regression analysis manifested that the negative correlations were significant(P<0.05, or P<0.01)between the Shannon-Weaver index and dominant degree, however, the Shannon-Weaver index was significant correlated positively to well-distributed degree. The densities of phytoplankton ranged from 485.9×104 to 35459.8×104 cell/L. The densities of phytoplankton were negative with the change of contents of inorganic nitrogen and sulfureted hydrogen in the early period, and almost increased in-phase in the later stage in the high-order punctilous animal husbandry cultivate method, but the densities of phytoplankton were negatived with the change of contents of inorganic nitrogen and sulfureted hydrogen all the time. The change of pH was positively correlated to the density of the phytoplankton in every cultivate method. The comprehensive analysis concluded that the high-density culture should select the high-order pool hierarchical punctilous animal husbandry method and the lower one should select the culture in sea-water soil pool.