In aquaculture this mechanism has been overlooked. Baker's yeast and most mono-species unicellular algae lack the physical properties to generate fecal pellets which results in lose, partly non-soluble excrements that create floccules. These difficult-to-separate
flocculesb hamper the free passage of the water through the mesh of the filters during
harvest prolonging and intensifying the already stressful handling procedure (Suantika et al., 2003). Due to the increased pressure on thefilter, the staff is often forced to intervene (prefilters, extra aeration,regulation of the fiow, shaking of the filter,...) which is not only a loss in labor effectiveness it also has a direct impact on the rotifers which are injured, killed or possibly trapped in the floccules. Injured rotifers are prone to secondary infection and fouling, while floccules and dead or trapped rotifers form a secondary biohazard to
fish