大泽山水库施肥养鱼条件下浮游生物的变动

本文报道1988年施肥和网箱养鱼的大泽山水库中浮游生物种类组成、生物量、叶绿素总量和浮游生物优势种的季节变动和在施肥周期中的变动。浮游植物生物量全年有5个高峰,在每一施肥周期中都有一个高峰;浮游动物生物量全年有3个高峰,在施肥周期中,夏季出现一个高峰,但在秋季并未出现明显的高峰。文中还讨论了影响浮游生物生物量变动的主要因素。

VARIATIONS OF PLANI}TON UNDER FERTILIZATION FOR FISHFARMING IN DAZESHAN RESERVOIR

Dazeshan Reservoir of Shandong Province is a middle-sizedone in which a complex fishfarming, i.e., fishculture with artificial fertilizationintegrated with net cage culture, was conducted. The seasonal variations of speciescomposition, biomass, amount of chlorophyll and dominant species of planktonand the variations of those factors in the summer and autumn of the fertilizationcycles in the reservoir in 1988 were reported. 48 species of phytoplankton was found. Its yearly average biomass was11.2mg/L. Cryptophyta dominated absolutely over the year. There were five bio-mass peaks, one in the spring and the other four in the summer and autumn in1988, of which the highest one appeared in the late summer. As for zooplankton, 28species was found and its yearly average biomass was 0.74mg/L, and there werethree biomass peaks in the two same seasons mentioned above. Phytoplankton bio-mass reached a peak in each fertilization cycle observed, but the time taken to rea-ch the peak and the duration of the fertilization effect were shorter in the summerone. Zooplanktonbiomass attained to a peak in the summer fertilization cycle,however, it was only fluctuating and rising gradually and did not appear a obviouspeak in the autumn one. The affecting factors on the variation of plankton in the reservoir are also dis-cussed.