抑食金球藻对翡翠贻贝生长及摄食的影响研究

Effect of Aureococcus anophagefferens (brown tide) on growth and feeding of the mussels Perna Viridis

在室内以翡翠贻贝(Perna viridis)为对象,研究单种抑食金球藻(Aureocuccos anophagefferens)及其与亚心形四爿藻(Tetraselmis subcordiformis)混合藻液条件下抑食金球藻对贻贝的生长和摄食的影响。结果表明,抑食金球藻对翡翠贻贝的生长和摄食均有显著的负面影响。单种高、中浓度抑食金球藻组贻贝的鲜重、干重及无灰分干重均显著低于混合藻组,贻贝的个体生长条件指数(CI)下降明显,其下降率甚至高于饥饿组。混合藻组中贻贝的CI、软组织的鲜重、干重、无灰分干重等均显著低于对照组,其抑制程度与混合藻组中抑食金球藻浓度有关,当混合藻组中抑食金球藻浓度较大时(≥4×105 cells/mL),贻贝的上述指标更低。四组混合藻中贻贝的摄食率也均显著低于对照组,抑食金球藻对贻贝的抑食作用也与其藻细胞密度有关,混有较高密度抑食金球藻组中贻贝的摄食率更低,说明抑食金球藻并非因其个体太小而不能被贝类正常摄食,可能产生了某种生物活性物质抑制了贻贝的摄食和生长,亚心形四爿藻能在一定程度上可以缓解抑食金球藻对贝类摄食和生长的抑制作用。

The effects of brown tide algae species Aureocuccos anophagefferens and its mixture with Tetraselmis subcordiformis on the growth and feeding of the mussels Perna viridis were investigated in laboratory.The results showed that A.anophagefferens had a significant negative effects on the growth and feeding of mussels Perna viridis.The soft tissue fresh weight,dry weight and ash free dry weight(AFDW) of mussel fed on both high and medium cell densities of pure culturing A.anophagefferens were significantly lower than those of messel fed on mixed algae groups,the growth condition index(CI) of mussel decreased significantly as well,and the decrease rate was even lower than those mussels treated with starvation.The CI,fresh weight,dry weight and AFDW of mussels exposed to mixed algae group were significantly lower than control groups,and the decrease rate was related to the concentration of A.anophagefferens in mixed algae groups.When the concentration of A. anophagefferens in mixed algae group was higher(≥4×10~5cells/mL),the above indexes of mussels were even obvious lower.The feeding rates of mussels exposed to the mixed algae groups were significantly lower than that in the control group.The inhibitory effect on mussel feeding was also related to the cell density of A.anophagefferens,and the ingestion rate of mussel exposed to the groups of mixed high concentration A.anophagefferens was lower than that in the control group.These results suggested that the inhibitions were not only because A.anophagefferens cell size was too small to be ingested normally by mussel,but also the algae species could produce some toxic substance that inhibited the feeding and growth of mussels.To some extent,the inhibitory effect could be alleviated by the behaviour of mussels fed on T.subcordiformis simultaneously.