HE Jiabei, ZHAO Xiaowei, YANG Lufei, JI Shenglei, ZHAO Yunxing, ZHAO Qiang
To improve the aquaculture benefits of shallow sea bivalves aquaculture industry in northern China, limpet (Neptunea cumingii) was polycultured with blood clam (Scapharca broughtonii), zhikong scallop (Chlamys farreri), bay scallop (Argopecten irradians), Pacific oyster (Crassostrea gigas) and mussel (Mytilus galloprovincialis) with different sizes and limpet, blood clam, zhikong scallop, and bay scallop were monocultyred in abalone cages disposed in an outdoor pond at Muping county in Yantai, Shandong province, at water temperature from 4.8 °C to 17.4 °C and salinity from 30 to 31 from October to November to evaluate the effects of limpet predation on the bivalves and growth of the culture animals in the integrated aquaculture of limpet with bivalves. Meanwhile, the food item composition was analyzed in the stomach of limpet under natural conditions based on DNA barcode technology. The results showed that the limpet had very low predation rates of (0.00%-2.50%±5.78%) on bivalves with different sizes, with significant difference in predation rates on the same species of large and small bivalves. Only prey on bay scallop at polyculture of multiple species of bivalves was observed in high-density and low-density limpet groups, with very low predation rates of 2.50%±6.83% and 0.63%±2.50%, respectively, and without significant difference in predation rates compared to other bivalves in the same group. The predation rate of the limpet on bivalves was found to be relatively high (4.64%±10.36%) at low temperature, with significant difference compared to high temperature. The limpet had no death, and had weight gain rate ranging from 16.83%±2.76% to 22.85%±5.34% in the integrated aquaculture, without significant difference in weight gain rate in different modes. The limpet and bivalves had weight gain rates of 19.28%±0.62% in high density integrated modes and18.37%±1.79% in low density integrated modes, without significant difference between the two groups. There was 21.12%±14.12% of weight gain rate in the feeding group, without significant difference between the feeding group and unfeeding group(18.73%±3.63%) and without significant difference in wet quality and survival rate in the same bivalve species between the integrated aquaculture mode and the individual aquaculture mode. In natural conditions, the limpet had complex food items, including 14 classes from multiple sources, including Mammals, Embryophytes, Actinopterygii, and Saccharomycetes, indicating that the bivalve vitality was the most important selection condition for limpet to predate in the integrated aquaculture mode. The size and species of bivalves had lower priority for limpet to predate, which provides ecological disease prevention capabilities for this mode. The integrated aquaculture mode was not shown to be significant impact on the growth and survival of limpet and bivalves, the limpet growing rapidly in this mode and showing the potential to become the main breeding animal. The main energy sources for the growth of limpet may be derived from marine sediments and attached organisms under the condition of feeding on bivalves. The integrated aquaculture mode is conducive to the sustainable and healthy development of bivalve aquaculture industry in shallow sea in northern China, with the value of demonstration and promotion.
and 4.64 mg/L for chemical oxygen demand (COD) prepared by ammonium chloride, sodium nitrite and glucose and Escherichia coli to verify the O3/UV water treatment system for the elimination effects of TAN, 
and COD in water. The results showed that the O3/UV water treatment system effectively eliminated TAN, 
N, COD, and E.coli from water, with removal rates closely linked to the initial concentrations of the targeted pollutants. There were decrease in removal rates of TAN and 
-N, and COD in water were shown to be decreased to 1.57, 0, and 1.37 mg/L, respectively, with removal rates of 29.0%, 100%, and 70.3%, respectively at initial concentrations of 2.21 mg/L for TAN, 0.59 for 
and 4.61 mg/L for COD in the koi culture water, after 12 hours of treatment in the O3/UV water treatment system. Additionally, after passing through an activated carbon tank, the concentration of ozone in the water was decreased to 0.04 mg/L, which no longer affects koi culture. The finding demonstrates that the O3/UV water treatment system can rapidly and effectively remove pollutants from koi culture tailwater, showing potential applications in ornamental animal culture water treatment.
N and 59.99% for COD in aquaculture water. The optimal preparation of immobilized pellets was found under conditions of alginate bacterial solution containing 2% sodium alginate and 4% activated carbon cross linked with 4% calcium chloride for 24 hours. The purification effect of the composite carrier immobilized bacterium pellets on the aquaculture water was better and longer in the outdoor enclosure than that in the free bacteria, with significantly lower contents of TAN, 
and COD in enclosures treated by immobilized Bacillus subtilis in the enclosure test at the end of the 21 days than those in the free bacteria groups and the control groups (P<0.05), only 29.14%, 69.23%, 12.23% and 68.30% compared to the control group, respectively, indicating that the water purification effect of immobilized bacterium pellets on composite carrier with adsorbent matrix was significantly better than that in single immobilized bacterium pellets and free bacteria without adsorbent matrix. The findings provide reference for the application of immobilized microorganism technology in aquaculture.
