Artificial seed production and cultivation of the edible brown alga Sargassum naozhouense Tseng et Lu

Sargassum naozhouense Tseng et Lu is a perennial brown alga found in the coastal area of Leizhou Peninsula, Guangdong, China, and it has considerable commercial potential for further exploitation. To develop a commercial-scale aquaculture of this edible species, the growth, maturation, artificial seeding, and cultivation of this alga and harmful co-existing organisms were investigated from March 2009 to April 2010. In the alga’s natural environment, the receptacles began to form in April and bloomed in May. Artificial cultivation reduced the time required for thalli maturation by at least 1 month. Seedlings were cultured for 1 month in tanks with flowing seawater, until the seedlings had grown to a length of 1.5–2.0 mm. The seedlings were then transferred to a nursery culture ground at sea for an additional 5 months until they reached a mean length of 5 cm. The control of fouling organisms was crucial for establishing a successful seedling culture both indoors and at sea. Afterwards, 45,000 germlings were reared in a grow-out sea area using a full floating raft cultivation system on 2-km-long ropes. The mean yield from this rearing was 1,750 kg wet wt. km−1 culture rope during the farming period of 95 days. Adult S. naozhouense has a greater tolerance to high temperatures than other cultivated Sargassum species and can withstand a temperature as high as 33.7 °C. A preliminary commercial cultivation protocol was also established. The results demonstrate the potential to aquaculture S. naozhouense at relatively high seawater temperatures.