Non-toxic strains (by mouse toxin assay test) of unicellular Microcystis aeruginosa and short filamentous Anabaena cylindrica were fed to Daphnia carinata in the laboratory at an algal volume concentration of 4.0 mm3 L-1 at 24 +/- 1-degrees-C. The filtering rates (FR, mL animal-1 hr-1) of D. carinata on M. aeruginosa and A. cylindrica increased with increasing body length (L, mm), and were expressed as a power curve: FR = 0.061L2.09 and FR = 0.232L2.09, respectively. The potential for control of natural blue-green algal populations by D. carinata grazing is discussed briefly.
