Tripneustes gratilla, usually called sea urchin, mainly distributes in the warm waters of the Indian Ocean and the Pacific Ocean. It grows very fast and is the commercial sea urchin with the largest size in Japan. Sea urchin is one of the main edible urchins in Taiwan and could be technically cultured. However, the main food source of sea urchins in the wild is macroalgae which leads to limitations in the utilization of the business model, including 1. The resource of suitable algae is limited. 2. The quantity and quality of algae change over time. 3. Competition with other marine organisms for the utilization of algae. 4.
Collection of algae costs a lot. 5. Difficult storage of algae with the quantity in business model. Therefore, the development of the feed for sea urchins influences the development of sea urchin culture. The objective of the feed is to enhance the growth of body size (shorten the time to product launch) and gonads. Protein is the main factor required during growth. The amount required is between 20~50% according to the species of sea urchin and different stages of growth. The source of proteins in aquacultural feed is mainly fish powder. However, the decrease of fishery resources leads to constant increase of costs of feed. Therefore, vegetable proteins as the source of protein have achieved considerable results in general feeds. Some researches have shown that soy protein could be used as an alternative source of protein in sea urchin feed. And, it was found that replacing fish powder with 50% soy protein would lead to the best effect on the development of sea urchin gonads. The increase of the attractability of feeds could indirectly decreases the cost. Therefore, the overall objective of this project is to develop two-stage artificial feed for the growth and development stages of sea urchins, use vegetable proteins to replace 50% of fish meal to reduce feed costs, and add 5% of Sargassum algae powder as an attractant to stimulate the feeding rate and increase the growth rate as well as reduce the cost of fish farmers. The stability test of the sea urchin feed will be developed this year. With the addition of vegetable protein alternatives and attractant, the overall growth efficiency, survival rate and protein efficiency ratio from 2-cm to 6-cm gonad after feeding artificial feed diets (15, 20, 25, 30 protein percentages) to sea urchin will be observed for providing reference of the optimal protein-feed ratio and feeding amount for further technology transfer.