The Growth, Reproduction And Artificial Seaweeds Beds Construction Of Three Species Of Sargassum

Sargassum beds plays an important role in the coastal marine ecosystem, thus the establishing of Sargassum farm will have great value on ecology and economy. Sargassum is important economic algae of Guangdong province, which is high quality feed for abalone, sea cucumber and other oceanic economy animals, and also can be sued as industrial raw materials of alginate. People in coastal areas has increased the dependence on utilization of Sargassum with the improvement understanding of its value. However, a large number of natural Sargassum beds had degraded or lost because of the environmental degradation coupled with sea water quality decline and other factors. So establishment of permanent Sargassum fields artificially is becoming increasingly important.In this paper, the wild growth pattern of three species of Sargassum located in donghaitou of laozhou island was investigated, ripening and propagation flourishing periods were also recorded. In order to accumulate the biology and ecology data of the three species of Sargassum, thus providing a basis for artificial breeding and seaweed farm building, the ovulation, young sporophyte growth and seedlings domestication of three species of Sargassum and two kind methods of artificial seaweeds beds building were studied. The main conclusions are as follows:1. The ripening and propagation time vary from the three species of Sargassum located in Leizhou Peninsula, with Sargassum henslowianum mature first, begin to breed at the end of March, the next comes the Sargassum hemiphyllum var.chinense, begin to breed in mid-April, and Sargassum integerrimum mature last, begin to breed at the beginning of June. Although there are significant differences in the ripening time, but growth cycle of all the three species of Sargassum can be divided into four stages, namely the telogen phase,growth, maturity and aging period. The aging period last about one month after breeding period. Then the algae gradually decay with the rest of rhizoids pass through temperature period on the rocks. The resting period of the three species of Sargassum starts at different time, but all ended in november and into the growth phase. During this period, the algae grow faster, in the month before maturity, up to 10 cm ? day-1 and above. The growth in maturity is not obvious, while the biomass has gained a significant increase with the formation of receptacles, after breeding, algae quickly get into a short aging period, andbegin the next life cycle.2. Three species of Sargassumˊdevelopment of fertilized eggs belong to an 8-core type egg, fertilized eggs all directly grow without hibernation, and form rhizoids fixing on the base within 48 hours. In this study, bricks and nylon curtains were used as attachment base to breed seedlings, the results showed that the seedling density of the three species of Sargassum on both attachment were not so different at the beginning,, but after 60 days of culture, three species of Sargassum with the performance of the smaller seedling density but the larger algae on brick attachment base, and the larger seedling density with the smaller algae on the nylon curtain; After domestication at different time, the seedling density of three species of Sargassum were significantly decreased on nylon curtain, but seedlings growed faster on nylon curtain,. After domestication, frond were longer than the seedlings on brick curtain, and Sargassum henslowianum had the longest domestication time with the longest frond(77.8±21.6 mm).3. The mosaic and bundle method were used to transplant the seedlings to the two algal reefs respectively, the results showed that the mosaic method was bad, while the bundle method could gain a higher survival rate of seedlings and this seaweed Sargassum could mature, thay used the rhizoids attached to the artificial algae reef to spend the telogen phase. Three kinds of Sargassum in the first round of the life history exhibited a common feature: the length was much more less corresponding to the same wild species of Sargassum. The rhizoids reserved on the reef could birth seedlings, simultaneously in the corresponding growth with the wildlife resources, there is no significant difference in the length of the frond and maturation time, then the permanent Sargassum farm was formed.4. Nylon curtain is more suitable as nursery attachment base of three species of Sargassum, the seedlings of three species of Sargassum still requires a certain degree of acclimatization before they can be transplanted to the complex inter-tidal environment for building Sargassum farm, construction of artificial Sargassum farm combining with full floating raft domestication and bound method is a possible way.