1 3 FEEDING PENAEID SHRIMP

Until about two decades ago, all shrimp supplied to the world markets was harvested from the oceans. Presently, the ocean fisheries for shrimp are at near maximum sustainable yield. Shrimp catches from the sea are unpredictable due to uncontrollable natural phenomena. Pollution and other human activities have disrupted the ecology of shrimp nursery grounds in many areas. Energy requirements for harvesting ocean shrimp are high; diesel fuel represents more than 50% of the total operating costs. Therefore, the increase in world demand for shrimp is dependent upon an increase in production through aquaculture. In 1986, pond-raised shrimp represented an estimated 6% to 8% of the world shrimp supply. By 1996, according to the Food and Agriculture Organization (FAO) of the United Nations, farmed shrimp accounted for 43% of the estimated world shrimp consumption. Marine shrimp farming has been practiced for centuries in many Asian countries using the traditional method of trapping and holding wild shrimp which enter coastal ponds through the incoming tidal water exchange, as shown in Figure 13.1. However, the development of modem shrimp farming technology began in the 1930's when Hudinaga first successfully spawned and reared larvae of Penaeus japonicus in captivity. Since then technology has been developed for mass production of marine shrimp larvae. Within the past 20 years, several shrimp species of the penaeid family, such as Metapenaeus ensis, Penaeus japonicus, P. monodon, P. indicus, P. mergiensis, P. aztecus, P. setiferus, P. schmitti, P. chinensis (also known as P. orientalis), P. penicillatus, P. stylirostris and P. vannamei, have been matured, spawned and their larvae reared in captivity. As shrimp farming has expanded, the production methods have shifted from traditional extensive to semi-intensive and intensive systems, utilizing modem facilities, equipment and management techniques aimed at high yield production. Natural food constitutes an important source of nutrients for extensive culture, whereas artificial feeds are the primary source of nutrients for semi-intensive and intensive practices. In semi-intensive and intensive culture systems, feed represents 30% to more than 50% of the total variable costs. Thus, the use of least-cost, nutritionally balanced feeds and good feeding practices are fundamental to successful shrimp farming. This chapter provides an overview of culture practices, nutrient requirements, feeds and feeding practices for penaeid shrimp.