Introduction
Green seaweeds from the genus Caulerpa particularly Caulerpa lentillifera and Caulerpa racemosa are consumed all throughout the Philippines. Both species are called sea grapes because of the grape-like tiny spherical beads tightly packed together on the stems. C. lentillifera or locally known as “lato” is more preferred because of its light, refreshing taste, soft and succulent texture (FAO, 1999). It is a popular seafood delicacy eaten as raw dip only in vinegar or used in fresh salads with other seafood and vegetables. It has gained recognition in the international seafood industry because of its high nutritional value. According to Saito et al. (2010), it has relatively high polyunsaturated fatty acids including omega 3 fatty acids. It has also high mineral content such as zinc and iron and trace elements including cobalt, selenium and valium that meet daily body requirements (Peña-Rodriguez et al., 2011).
This seaweed is adaptable to a variety of environments making it suitable for cultivation in ponds. It naturally inhabit a wide range of substrate consisting of rubbles to over 50 meters deep, sand on reef flats and shallow, muddy lagoons and forms beds and meadows in excellent condition habitats. However, it is sensitive to changes in salinity being stenohaline; salinities lower than 30 ppt result to poor growth and lower than 25 ppt salinity cause mortality.
Trono (1988) accounted the cultivation of C. lentillifera in the country and studied the culture method. It started in early 1950s when it was accidentally introduced in fishponds with some other seaweed as feed in the province of Cebu. The culture technology of this species is relatively simple. Existing milkfish ponds can be used for cultivation. Cuttings are used as planting material and are planted one meter apart in the pond bottom. After the cuttings have rooted and started to grow, regular water exchange is needed to maintain a fresh supply of nutrients and maintain good water quality. Fertilization is done during the later stage when the seaweed is almost harvestable and the natural nutrients may no longer available to support the biomass. Fertilizer is applied using the “teabag” method wherein sacks of fertilizers are suspended in the ponds. Paul & de Nys, 2011 evaluated the use a culture vessel or tray in the cultivation of C. lentillifera. The vessels are square perforated plastic trays with an area of almost 1 m2. Culture trays were rotated every 4 days, moving randomly positions with the system. They found out that this method is highly feasible.
The increasing demand for domestic consumption and international trade has led to the commercial cultivation of the species. Among the other varieties of Caulerpa, commercial aquaculture production only exists for C. lentillifera (Paul & de Nys, 2008). Nonetheless, different culture methods for large scale production of the species in the country are rarely evaluated. The development of a practical commercial production system will significantly contribute to increase in biomass yield and control of production cycles.