Size selective feeding of Anodonta calipygos, a phytoplanktivorous freshwater bivalve, and viability of egested algae.

Abstract

Anodonta calipygos, a freshwater bivalve, filtered only a small portion of algae suspended in the inhalant water, and particles ranging from 510 μm tended to show a high retention efficiency. The bivalve showed the highest preference for green algae ranging from 510 μm, and an ability to feed selectively on algal cells physiologically in good condition. Only a small portion of chlorophyll-a in the algal cells ingested by the bivalve was reduced to phaeophytin-a during the intestine passage. The egested algae were viable and showed some photosynthetic activity. The possibility of direct recycling of egested algae was discussed.