Studies Of Juvenile Culture Of Ruditapes Philippinarum "Zebra Clam"

1.The contrast and analysis of growth and survival of Zebra clam in two different farming modes.From May to October 2015,we conducted a study in Zebra clam’s growing characters in two different farming modes. The result shows the shell length and wet weigth of Zebra clam in bottom sowing culture are obviously higher than those reared in suspended-cage, while the survival rate is significantly lower. The average shell length and wet weight of those in the lantern for cultivating abalone cage are higher than those in the lantern for cultivating scallop cage. It was found that breeding in the lantern for cultivating abalone cage was superior to breeding in the lantern for cultivating scallop cage.The average shell length and wet weight of the lantern for cultivating abalone cage 50 are higher than those of the lantern for cultivating abalone cage 100. The significance of difference is P<0.05. While the significance of difference of the average shell length and wet weight of the lantern for cultivating scallop cage 50 and the lantern for cultivating abalone cage 100 had no significant difference(P>0.05).However the average of the lantern for cultivating scallop cage 50 is higher than the lantern for cultivating scallop cage 100.In general, the average shell length and wet weight in the experimental group of lower growth density are higher. It was illustrated growth density is one of the growth-limiting factors. The aquaculture water depth had no significant effect on the growth or viability of Zebra clam that reared in suspended-cage. As a disagreement of former research,it was maybe concerned with small water layer spacing or different culture cycle. This research could provide basic data and scientific basis for healthy and efficient aquaculture of Zebra clam.2 The contrast and analysis of nutrient components of Zebra clam in two different farming modes.Nutrient components play an important role in the quality evaluation of shellfish. This experiment researched the formation and content of general nutrient components, amino acid, fatty acid of Zebra clam in two different farming modes. It turned out that in the general nutrient components, moisture contents of Zebra clam in two different farming modes were close. The crude protein and ash contents of Zebra clam in bottom sowing culture were higher than those reared in suspended-cage. It maybe applied to better water quality and plenty of bait in pond culture. While the content of crude fat was lower than that in suspended-cage. It perhaps related to the water temperature difference in two aquaculture sites.The content of glutamic acid in the organs of Zebra clam in Panjin bottom sowing culture is much higher than that of Zhangzi Island suspended-cage. Therefore, the taste of Zebra clam in Panjin bottom sowing culture is better than those of Zhangzi Island suspended-cage.The EAAI of Zebra clam in Panjin bottom sowing culture summed up to 84.50,while that of Zhangzi Island suspended-cage was only 68.89.This result showed that the nutritional value of amino acids in Panjin bottom sowing culture had an advantage over that of Zhangzi Island suspended-cage.The content of unsaturated fatty acid, EPA,DHA in Zhangzi island suspended-cage was higher than that in Panjin bottom sowing culture.This result showed that Zebra clam in Zhangzi Island suspended-cage was more suitable than that in Panjin bottom sowing culture in supplement essential amino acids for human bodies.3.The contrast and analysis of heavy metal content of Zebra clamin two different farming modes.With the development of the industry, the heavy metal pollution to the aquatic organism has aroused people’s attention. This experiment studied the composition and content of heavy metals of Zebra clam in two different farming modes. The result showed that the kinds of heavy metals were exactly the same, but the content was slightly different. The average contents of Cu、Pb、Zn and Hg of Zhangzi Island Zebra clam were higher than those of Panjin’s. But the difference was not obvious.However the average contents of Cd and As of Panjin were significantly higher than those of Zhangzi Island.The two different farming modes and the difference of heavy metals enrichment in two areas were the main causes of the result.The Pi of Cu、Pb、Zn、Hg and As of Zebra clam in two area are relatively low and pollution index is less than 0.5.The Pi of Cd of Panjin bottom sowing culture is 0.533 and it exceeds the limit,but the Pi of Cd of Zhangzi Island suspended-cage is 0.164 and it is lower than the standard limit.