Abstract
The survival, development, emergence and effect on water quality of the common Japanese chironomid, Chironomus yoshimatsui, were examined under different combinations of food dose and larval density in a container (φ15×H 9cm). Emergence rate was higher than 80% in a combination of 5g dose and 100 ind. density. Mean adult weight was about 0.7mg or higher than 0.7mg in 10g dose. Total survival rate was higher than 50% in the combinations of 2.5g and 100 ind. and 5g and 100 or 200 ind. Reduction in PO_4-P concentration of the rearing water was higher than 20% in the combinations of 2.5g and 100 ind. and 5g and 200 ind. About 50% or higher than 50% of reduction in protein concentration was obtained at 5 or 10g dose. The results suggest that there is a possibility of improving water quality by cultivating this species in waste water.
