Abstract: The ingestion rate of copepods, Schmackeria poplesia and Oithona sp. on Prorocentrum micans was studied in a seawater enclosure with serious water bloom of P.micans. The mean ingestion rate of copepods with a body length>125mm,which included adult and some copepodites of S.poplesia, on P.micans was 12140 cells·ind^-1 ·d^-1, while that of other copepods with a body length <125mm, which included some copepodites of S.poplesia and both adult and copepodites of Oithona sp., was only 1133 cells·ind^-1 ·d^-1.During experimental period, the concentration of P.micans in the enclosure was 850～16170 cells·ml^-1, and the population specific growth rate of the algae ranged from -0.002 to 0.150. It is clear that the ingestion of copepods was not enough to inhibit the growth of P.micans population, if P.micans was in growth phase. Therefore, the copepods in enclosure could not prevent from occurrence or development of P.micans bloom.

Key words: Copepod, Ingestion, Prorocentrum micans, Enclosure