高产成鱼池蓝绿色裸甲藻水华的研究

由蓝绿色裸甲藻(Gymnodinium,sp．)形成的蓝绿色水华是无锡渔区高产鱼池典型水质之一。本文对该藻的形态特征、生态、池塘培育和控制以及对鱼类的影响进行了研究。蓝绿裸甲藻水华具喜温、喜光、喜有机氮肥,喜红褐色水色(生物因子),且对外界环境的变化十分敏感等生态特点。蓝绿裸甲藻水华池的理化条件较差,特别是藻体繁殖过度,极易恶化水质,造成鱼类泛池。采用增施有机氮肥、合理使用增氧机、加水等综合措施可促进和控制该藻的繁殖。经鱼类消化道镜检表明,蓝绿裸甲藻能被鲢、鳙鱼及鲤、鲫、罗非鱼鱼种大量摄食,并被鱼类消化。对无锡河埒渔业一队成鱼池三年统计,蓝绿裸甲藻水华池的鲢鳙鱼净产量比无水华池高33．4～37．5％。

A STUDY ON THE "WATER BLOOM " OF GYMNODINIUM IN HIGH--YIELD FISH PONDS

The bluish green pond "water bloom" is generally recognised as the typical waterquality of most high-yield fish ponds in Wuxi fish farms. A study of the ecology ofthe fish pond, the "water bloom", the biology of the dominant algae and its value as fishfood has been carried out. It was found that the bluish green color of the pond water mainly is formed bythe "water bloom" of a dinoflagellate(Gymnodinium sp.), which multiplies enormouslyunder the favorable conditions of adequate illumination, warmth, and heavily manuredwaters. It is very sensitive to environmental changes. If the algae are over populated,the pond water would damage and cause the suffocaiton of the pond fish. The integratedmanagement of heavily manuring, continous addition of freshwater, and the reasonableoperation of aerators will promote and control the multiplication of the algae. Microscopical examination on the digestive tracts showed that large amount of thealgae were taken by the silver carp, bighead carp and the finglings of common carp,crucian carp and tilapia. Obviously the "water bloom" of the algae effects greatly the production of fish pond.According to the statistics of the Fishery Team No.1 of Helie People's Commume, thefish ponds having "water bloom", the net yield of silver carp and bighead carp willincrease 33.4-37.5%.