Polyculture of juvenile sea urchin（ Strongylocentrotus intermedius）with juvenile sea cucumber （Apostichopus japonicus Selenka） at various stocking densities
WANG Ji-qiao, CHENG Xin , YANG Yi,WANG Nian-bin
1. School of Life Science and Technology, Dalian Fisheries Univ. , Dalian 116023, China; 2. Liaoning Ocean and Fisheries Research Institute, Dalian 116023, China
Abstract: Sea urchin（ Strongylocentrotus intermedius）juveniles weighing （ 1.7±0.7） g were stocked into 24 plastic tanks of each 45 cm× 31 cm×30 cm at a rate of 10,20 and 30 individuals per tank and polycuhured with juvenile sea cucumber （Apostichopus japonicas Selenka） averaging （ 1.8 ± 0.5 ） g in body weight at water temperature of 13.0 -23.0 ℃ for 151 days. The sea urchin were ad libtum fed kelp （Laminaria japonica） and the sea cucumber unfed. Specific grow rate and survival were found to increase by 28.46%, 2.86% ; 33.99%, 10. 35% and 25.52%, 23.13% in the sea urchin polycutured with sea cucumber at a rate of 10, 20 and 30 individuals per tank, respectively. There was 1.50%, 7.99% and 1.85% lower feed conversion ratio in polyculture than in mon- oculture for each stocking density of sea urchin. In polyculture water, ammonia - N level was registered low and constant, and high dissolved oxygen level was observed. The density of sea urchin showed no significant influence on approximate composition of sea cucumber （P 〉 0.05 ）. Factors affecting polyculture of sea urchin with sea cucumber including optimal ratio of sea urchin to sea cucumber were discussed.
2007, Vol. 22 
