Food Consumption of Juvenile Haliotids in Laboratory Experiments

Abstract

Daily amounts of food intake and feces excreted by juvenile abalone Haliotis discus and H. d. hannai, were measured on a bimonthly basis with Wakame (Undaria pinnatifida, Phaeo-phyceae) for food, and then the annual amounts of food consumption and the bimonthly assimilation efficiencies were derived by species. The daily food intake by H. discus showed a downward tendency from 45mg dry weight in October to 26mg in April, but in the subsequent period from May to October it increased to the higher level of 53-67mg. That by H. d. hannai was 28mg in October and descreased to 21mg in February, but it also increased to the 51-56mg level in the period from May to October. The annual amounts of food consumption by H. discus and H. d. hannai were about 16g and 13g in dry weight, respectively.
The caloric values of Wakame for food and feces were measured with a bomb calorimeter. The daily amounts of food intake and feces excreted in the unit of weight were thus con-verted into their equivalent caloric values. The bimonthly assimilation efficiencies calculated by using such estimates in terms of caloric value, showed a fairly stable level of some 70-80% in both species.