| Growth of molluscs raised in coastal zones, where the water exchange rate is low, appears to be limited, once a certain biomass level is attained, by the availability of food, making it necessary to determine as accurately as possible the trophic capacity of an ecosystem. This paper analyses the various sources of food for molluscs. It would appear that dissolved organic substances play a major role, providing up to half the energy necessary for their metabolism. Particulate material is filtered by molluscs in proportion to their size, with optimum filtration rates varying with species. The negative effect on meat production of high mineraI seston rates is demonstrated, and an analysis provided of the respective role of each component of organic matter.... |
