Appetite and food consumption in the sea urchin Echinus esculantes L.

The importance of food intake due to sense of hunger (‘appetite’) and ‘social feeding’ in governing the rate of food intake was studied experimentally. The role of the degree of filling of the gut and the turnover time for food is discussed. Mean individual maximal food intake rate following 10 days of starvation was 2.8 g wwt Laminaria saccharina per 12 hours, decreasing smoothly within 36 hours to 0.4 g wwt per 12 hours (‘standard food intake’). Following 36 hours starvation, maximal food intake rate was again reached, giving a turnover time for food of 36 hours, and a voluntary food intake of 85 % of maximal consumption. In social feeding the same pattern was recorded, although maximal food intake rate was somewhat lower. The standard food intake was similar to that of the individual experiments, indicating that the maintenance of the standard energy requires a continuous intake of food.