Abstract
The grazing of toxic red-tide dinoflagellates by copepods and other zooplankters is not well-understood. Various zooplankters have been shown to ingest toxic dinoflagellates (Turner and Anderson, 1983; Tsuda and Nemoto, 1984; Uye, 1986), and by accumulating ingested toxins some zooplankters act as vectors for toxin dispersal through the food chain (A. W. White, 1977; 1979; 1980; 1981). Conversely, there are a variety of indications that certain red tide dinoflagellates can be repugnant to potential grazers. Some copepods feed poorly upon dinoflagellates that are highly bioluminescent (Esaias and Curl, 1972; H. H. White, 1979; Buskey et al., 1983) or toxic (Huntley, 1982; Huntley et al., 1986; Ives, 1985; 1987; Sykes and Huntley, 1987). Other copepods avoid dinoflagellate-rich waters (Fiedler, 1982; Huntley, 1982), or exhibit reduced appendage-beat activity (i.e. reduced feeding) in the presence of some dinoflagellates (Gill and Harris, 1987). Extreme physiological reactions (regurgitation, loss of motor control, rapid heart beat, death) can result from ingestion of some dinoflagellates by copepods (Sykes and Huntley, 1986).