Abstract: Improved sea urchin feeds are provided which are very efficiently utilized by sea urchins and significantly increase gonadal development. The feeds are semi-moist, stable, extruded solid pellets or bodies which sink in sea water and have protein and carbohydrate fractions as well as a moisture content of from about 12-40% by weight. The feed bodies have an as manufactured water activity of up to about 0.8, are storable at ambient temperature for a period of at least two months, and are self-sustaining in sea water for a period of at least about 24 hours. Preferred feeds include kelp, fish oil and humectant.