Toxicity of the Chrysophyte flagellate Poterioochromonas malhamensis to the rotifer Brachionus angularis

The toxicity of the chrysophyte flagellate Poterioochromonas malhamensis to the rotifer Brachionus angularis was investigated. Fed rotifers exposed to the flagellate experienced a mortality rate indistinguishable from starvation. Unfed rotifers exposed to the flagellate experienced a higher mortality rate. The mortality rate appears to depend on the flagellate concentration. Higher doses of flagellates resulted in quicker rotifer death. These laboratory results are consistent with the hypothesis that the occurrence of B. angularis in the field may be negatively related to the presence of P. malhamensis and related flagellates.