Culture of other edible seaweeds
The green algae Monostroma and Enteromorpha are cultivated in Japan. Monostroma isa highly priced species and may be cultured together with Porphyra or separately. The methods of culture are the same as for Porphyra, involving the collection of spores on hibiand growing them in intertidal areas near river mouths. Enteromorpha appears to be grown only along with Porphyra.
Another species cultured in the Philippines is the green alga Caulerpa, which is consumed locally as a fresh vegetable and also exported to Japan in fresh or dried form. Its culture is generally carried out in ponds with clayloam bottoms, and free from pollution as the plant is eaten fresh. The depth of water varies from 60 to 100cm, depending on the clarity of the water, and the optimal salinity is 30–32ppt. The water temperature is maintained between 27 and 30°C for good growth and, since the alga is rather sensitive to intense sunlight, the water depth is adjusted so that the plants are only just visible from the surface. The water management required to maintain the necessary temperature and light intensity makes it necessary to site Caulerpa ponds where exchange of water is possible on most days of the tidal cycle.A water pH above the optimum of 7–8 can result in stunted growth and tough thalli, and so is avoided.
Cuttings or fragments of the plant are generally spread on the pond surface, but many farmers embed one end of the cuttings in balls of clay so that they sink to the bottom rather than float around in the pond for long periods. About 1.5 tons of cuttings are planted for every ha of pond surface. Frequent fertilization with small quantities of inorganic fertilizers helps to improve growth. The plants can be harvested in about two to three months and if enough stock is left in the ponds, further planting will not be required.