Abstract:Two trials for Sargassum thunbergii seedling production and three times seedling nursery were conducted between 2007 and 2009 in Xiaoshidao of Weihai and Xuejiadao of Qingdao in Shandong Province. About 10 concrete ponds were employed as seedling production facilities, each with 2×5 m2. Parent strains were collected from different sites in Weihai, and it was proved that the local strain in Xiaoshidao was better for seedling production than the other S. thunbergii collected. Six types adherences substratum were used for seedling adherence, and it was indicated that bamboo curtain was the most efficient one, which yielded over 30 ind./cm2 of seedling densities. The total yielded seedling was 7,507,000 individuals in 2007, with average of 3.5 mm in length; while in 2008, it was 30,154,200 individuals with 3.2 mm in length. Early developmental observation showed that S. thunbergii seedlings owned higher survival rate and went through the normal development, but seedlings may be detached from the substrate when reached to 4 mm in length.The seedling density decreased to 0.2~1.0 ind./cm2 when the seedling length reached to 10 mm.
