Growth and grazing of a heterotrophic dinoflagellate, Gyrodinium dominans, feeding on a red tide flagellate, Chattonella antiqua

Growth and grazing of a heterotrophic dinoflagellate, Gyrodinium dominans, were examined in laboratory batch cultures. When Chattonella antiqua was used as prey, G. dominans grew at a rate of ca 0.9 d−1 (at 25 °C). Cell division of G. dominans was not affected by the light : dark period. Growth rate of G. dominans was significantly affected by temperature and was maximal within the range 25 to ≥ 27.5 °C. Rate of ingestion of C. antiqua (at ca 1 × 103 to 2 × 103 cells ml−1) by G. dominans was 3.8 prey cell−1 d−1 and growth efficiencies on the basis of carbon and nitrogen were 0.31 and 0.33, respectively. Results suggest the ecological importance of G. dominans in the disappearance of C. antiqua red tides.