Nemacystus decipiens is a useful edible alga in Japan. The authors tried to cultivate this alga at Omura Bay, western Kyushu, and obtained satisfactory results.
Neutral zoospores liberated from the sporophyte of Nemacystus decipiens which had been cultured in the laboratory or collected from fields, developed into fully grown adult thalli on laver nets, made of synthetic fibers, in the sea. The neutral zoospores which fastend themselves to the laver nets spread on October 30, in the early season of growth, germinated abundantly and they grew to about 10cm in length after about two months. After three to four months' cultivation the harvest of the plants per 10cm in length of net twine was 20 to 40g in wet weight. The macroscopic germlings of this alga germinated abundantly on the laver nets at all experimental localities, and the younger plants grew well at each locality in Omura Bay but they gradually decreased at other localities in the open sea.