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.

Abstract: A method for the cryopreservation of multicellular organisms characterized by rapid cooling and warming rates, exceeding 100.degree. C. per minute, to achieve 80% survival after storage in the frozen state. The method involves exposing multicellular organisms to a cryoprotectant medium, freezing the organisms and medium by cooling at a rate greater than 100.degree. C. per minute, holding the organisms and medium at a point below 0.degree. C. for a period of time, and cooling the organisms and the medium at a rate greater than 100.degree. C. per minute to an appropriate storage temperature depending upon the desired length of the storage period. The method is more specifically described with regard to aquatic organisms, and particularly described with regard to the cryopreservation of immature marine crustaceans.