The effect of concentration of suspension and inert material on the assimilation of algae by three bivalves

Assimilation efficiencies reported for bivalves vary, but different experimental conditions, in particular the concentration of the suspension at which the animals are fed, may affect the values found. Widdows & Bayne (1971) determined the assimilation efficiency forMytilus eduliswhen fedTetraselmisand they found that efficiencies decreased with increasing concentration of cells. Allen (1962) fed radioactively labelledPhaeodactylumtoMya arenariaandVenus striatulaand suggested that the amount of P recovered in the faeces was proportional to the amount of algae ingested rather than to concentration of suspension directly. However, Winter (1969) concluded that forArctica islandicaandModiolus modiolusthere was no relation between assimilation efficiency and concentration of algae.