Abstract: The ecological effectswere studied in a 200 cm×50 cm×80 cm polyculture tank of sea cucumberApostichopus japonicuswith sea lettuceUlva pertusarand green algaChlorella pyrenoidosaat two concentrations of 106cells/mL and 105cells/mL withoutwater exchanging in order to evaluate the interaction among sea lettuce,green alga and sea cucumber in the polyculture ecosystem.The results showed that the sea lettuce,and green alga effectively absorbed nitrogen and phosphorus in water for aquaculture.The green alga had significant inhibition of sea lettuce at alga concentration of106cells/mL and to some extent inhibition of sea lettuce at alga concentration of105cells/mL,atwhich water quality and growth of sea cucumber nearly were the same with those in the polyculture of sea cucumber with sea lettuce,especially restraining the growth of sea lettuce.
2016, Vol. 31 
