中华豆蟹对青岛海区贻贝的感染及危害初探

20 0 0年 10月～ 2 0 0 1年 12月 ,对青岛太平角养殖海区的贻贝寄生中华豆蟹的感染情况进行了调查。以肥满指数为指标 ,通过对感染和未感染贻贝的比较 ,分析了中华豆蟹对贻贝的危害程度。结果表明 ,中华豆蟹对贻贝的感染率为 2 .0 %～ 2 0 .4 %。2 0 0 0年 11月和 2 0 0 1年 11月出现 2次感染高峰 ,分别为 9.7%和 2 0 .4 % ;最低感染率出现于 2 0 0 1年 1月和 3月 (均为 2 .0 % )。感染强度为 1～ 5 ,多数为 1(占感染个体的 83.2 % )。贻贝所感染的豆蟹的性别及感染强度与宿主的大小有关。小个体贻贝仅见雄豆蟹感染 ,绝大多数雌豆蟹见于壳长大于 2 cm的贻贝。未发现同一宿主体内同时感染 2只或以上的雌豆蟹。在调查的 15个月中 ,有 11个月被感染贻贝的肥满度显著低于未感染的贻贝 ,且雌豆蟹对宿主肥满度的影响大于雄豆蟹

Investigations on the Prevalence and Adverse Effects of the Pea Crab, Pinnotheres sinensis, on the Mussel, Mytilus edulis, in Qingdao Area

Incidence of pea crab, Pinnotheres sinensis , on the blue mussel, Mytilus edulis, was investigated in Taipingjiao Bay, Qingdao, China from October, 2000 to December, 2001. The adverse effects of the pea crab on M. edulis were evaluated by comparing the condition index of the infected and uninfected mussels. The 15 month investigations revealed that the infestation percentage ranged from 2.0% to 20.4%. The lowest infestation percentage occurred in January and March, 2001. Two peaks of infestation percentage were observed in November, 2000 and November, 2001, which reached 9.7% and 20.4% respectively. The density of infection was 1 5, and the majority of mussels ( 83.2% ) were infected by single crab. The results also suggested that the infestation patterns, e. g., the density of infection and the sex of crab, were related to the size of the hosts. Small hosts tended to be infected by male crabs only, and most of the female crabs were present in mussels larger than 2cm (length), and no mussel was infected by 2 or more than 2 female crabs. In 11 months of the 15 months of the investigation, the indexes of condition of the mussels infected by crabs were significantly lower than those of the uninfested individuals, and female crabs brought about more adverse effects to their hosts than male ones.