A novel technique for the underwater suspended longline PVC pipe cage cultivation of ablaone in open waters
开放海区水下悬浮延绳式PVC 管养鲍新技术研究

To develop a novel technique for abalone cultivation in open seawater, the growth of abalone Haliotis discus hannai under three culture regimes was studied in Xinghua Bay within the period from March 2010 to September 2011. At the same time, the marine fouling colonizing on outward surface of the cultivation cages was also investigated. Moreover, the influence of typhoon on the mariculture facilities, including the floating raft with traditional plastic baskets and the longline system with PVC pipe cages was analyzed. The experimental sites were located in Kengkouwan, the traditional sheltered waters for abalone cultivation, and the open waters southwest of Xiaoridao, which is a newly developing abalone mariculture sea area. The results show that the average weight gain and survival rates of abalones in the longline PVC pipe cage group were (106.41±5.33) mg/d and 82.75%, higher than those in the traditional plastic basket groups deployed in newly developing open waters and sheltered waters (P<0.05). Winter and spring are the best time for abalone growth and a clear seasonal growth pattern was presented. The average daily growth of abalone in the longline PVC pipe cage group was higher than the other two groups (P<0.05). The abalones growth is much better in the open waters than the sheltered waters. The dominant fouling species in Xihua Bay were acorn barnacles Balanus reticulatus and B. trigonus. Heavy fouling generally occurred in summer and autumn, particularly in the upper part of the water column in the open waters. Moreover, the fouling biomass colonizing on the underwater PVC cages was less than those settling on the traditional plastic baskets (P<0.05). In summer and autumn, the techniques of the longline PVC pipe cage cultivation will provide an effective way to prevent harmful effects from typhoons, high temperature and heavy fouling on the mariculture facilities and cultivated populations.