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大珠母贝人工养殖过程中,幼贝死亡是一个严重的问题。1993年11月至1995年5月,采用现场调查、实验室研究和数理分析相结合的方法,在海南省临高县新盈珍珠贝养殖场自然海区吊养的A,B,C3批养殖贝和陵水新村珍珠贝养殖场养殖池吊养的D批养殖贝的发病和死亡情况进行了流行病学凋查.结果显示,大珠母贝幼贝群体的死亡是以暴发性方式发生,幼贝群体的大批量死亡高峰一般发生在4～6月龄期,8个月以后随着龄期的延长,死亡率显著降低.幼贝群体死亡率与贝体平均体长的关系是4cm以下的贝体死亡率较高,1～3cm阶段处于死亡高峰期内,5cm以上的贝体死亡率显著降低.大珠母贝幼贝群体的死亡率与类立克次体感染(即RLO平均感染严重度指数SI)之间存在显著的相关性,在RLO感染的高峰之后或当中部相应伴随贝群体死亡率的高峰,随着RLO感染的降低,贝群体的死亡率也明显降低。在4批养殖贝群体中,仅在A批养殖贝群体样本中发现有少量纤毛虫寄生(感染率为87.5％,感染强度为3.56个/10倍物镜).这几批幼贝群体的死亡与海水温度、盐度之间均无相关性。
Large bead mother shellfish breeding process, the death of young shellfish is a serious problem. From November 1993 to May 1995, using the method of on-the-spot investigation, laboratory research and mathematical analysis, a group of A, B, and C3 batch breeding shellfish cultivated in the natural sea area of Xinying pearl oyster shell farms in Lincoli, Hainan Province Epidemiological investigation on the incidence and mortality of D batch colony was conducted in the breeding pond of Lingshui New Village pearl oyster aquaculture farm.The results showed that the death of the shellfish population of Larvae oysters occurred in a violent manner, The peak of mass mortality generally occurs in 4 to 6 months of age, with the age of 8 months later, the mortality rate was significantly lower.The mortality rate of shellfish and shell body average body length is below 4cm shell body Mortality rate is higher, 1 ~ 3cm stage in the peak of death, shellfish body more than 5cm mortality was significantly lower. Large population of oyster shellfish population mortality and Rickettsial infection (RLO mean infection severity index SI), there was a significant correlation between the RLO infection peak or followed by the corresponding central population mortality rate, with the RLO infection decreased, the shellfish population mortality was significantly lower. Of the four groups of cultured shellfish, only a small number of ciliate parasites were found in the population A of the cultured population (infection rate was 87.5% and infection intensity was 3.56 / 10 times the objective lens) There is no correlation between seawater temperature and salinity.