香港巨牡蛎对不同密度2种浮游植物的摄食研究

Study on Clearance Rate and Filtration Rate of Different Size of Crassostrea hongkongensis Feeding on Two Phytoplankton with Different Density

【目的】探索大规模贝类养殖活动对养殖水体中不同密度和种类浮游植物的摄食差异和影响因素,为香港巨牡蛎滤食能力、控藻水平以及科学评估其养殖容量、生态影响的研究提供依据。【方法】在室内条件下研究大、中、小3种不同规格的香港巨牡蛎对不同密度的牟氏角毛藻、球等鞭金藻的清滤率和摄食率。【结果】在28℃水温和24‰盐度的实验条件下,香港巨牡蛎对牟氏角毛藻的单位个体清滤率和单位体重清滤率分别为1.29～5.49L·ind^(-1)·h^(-1)和0.62～1.84L·g^(-1)·h^(-1),对球等鞭金藻的单位个体清滤率和单位体重清滤率分别为2.58～8.40L·ind^(-1)·h^(-1)和1.18～3.17L·g^(-1)·h^(-1),香港巨牡蛎对牟氏角毛藻的清滤率及摄食率均低于球等鞭金藻。香港巨牡蛎单位个体清滤率和摄食率均表现出大规格>中规格>小规格的趋势,即单位个体的清滤率和摄食率随着贝类个体增大而增加。香港巨牡蛎对不同密度球等鞭金藻的单位体重清滤率和摄食率都随着个体增大而降低,但其对不同密度牟氏角毛藻的单位体重清滤率和摄食率随着个体大小的变化规律不一致。随着浮游植物密度的增加,香港巨牡蛎单位体重清滤率呈现出先升后降的趋势,在中等密度条件下香港巨牡蛎具有较高的单位体重清滤率。【结论】香港巨牡蛎的清滤率和摄食率除受牡蛎个体大小和浮游植物密度影响之外,还与浮游植物的种类、大小、营养质量等因子密切相关。

【Objective】Exploring the differences in ingestion and influencing factors of phytoplankton at different densities and species in aquaculture waters by large-scale shellfish aquaculture activities could provide evidence for the research on the filtration capacity,algae control level,scientific assessment of aquaculture capacity and ecological impact of the Crassostrea hongkongensis.【Methods】The clearance rates and filtration rates of three medium and small Crassostrea hongkongensis of different specifications,with different densities of Chaetoceros muelleri and Isochrysis galbana were studied under indoor conditions.【Results】The results showed that under the experimental conditions of 28℃water temperature and 24‰ salinity,the per individual and per gram clearance rate of Chaetoceros muelleri on Crassostrea hongkongensis were 1.29～5.49 L·ind^-1·h^-1 and 0.62～1.84 L·g^-1·h^-1 respectively.And the per individual and per gram clearance rate of Isochrysis galbana on Crassostrea hongkongensis were 2.58～8.40 L·ind^-1·h^-1 and 1.18～3.17 L·g^-1·h^-1 respectively.Crassostrea hongkongensis had lower clearance rate and filtration rate for Chaetoceros muelleri than those of Isochrysisgalbana.The individual clearance rate and filtration rate of Crassostrea hongkongensis showed the trend of large size 〉medium size 〉small size.That was the clearance rate and filtration rate of per unit individual increased with shellfish individuals.The clearance rate and filtration rate of per gram individual of different density Isochrysis galbana on Crassostrea hongkongensis decreased as individuals increased,but per gram clearance rate and filtration rate of Chaetoceros muelleri on Crassostrea hongkongensis varied with different densities and the variation of individual size was inconsistent.With the increase of the density of phytoplankton,the per gram clearance rate of C.hongkongensis showed a trend of rising first and then decreasing,which indicated that the C.hongkongensis had a higher rate of per gram clearance under medium density conditions.【Conclusion】In addition to the size of Ostreidae and the density of phytoplankton,the clearance rate and filtration rate of C.hongkongensis were closely related to the species,size and nutritional quality of phytoplankton.