外来物种沙筛贝对厦门马銮湾大型底栖动物的影响

Effect of exotic species Mytilopsis sallei on macrozoobenthos in the Maluan Bay,Xiamen in China

沙筛贝(Mytilopsis sallei)属于软体动物门(Mollusca)双壳纲(Bivalvia)帘蛤目(Veneroida)饰贝科(Dreissenidae),也称萨氏仿贻贝.20世纪90年代初作为鱼虾饵料被引到厦门马銮湾,逐渐成为附着生物的优势种,严重影响贝类养殖.在厦门马銮湾水域设计挂板实验和采集沉积物中大型底栖动物,获得了外来物种沙筛贝与其他大型底栖动物的时空分布数据.SPSS统计软件回归分析表明,沙筛贝与网纹藤壶(Balanus reticulatus)在挂板的垂直分布上呈负相关,沙筛贝高密度(大于105个/m2)时能导致网纹藤壶死亡,其主要原因是沙筛贝附着在网纹藤壶壳壁上,抢夺网纹藤壶食物而导致其饿死.无论是在挂板上还是在沉积物中,小头虫(Capitella capitata)、凿贝才女虫(Polydora ciliata)的数量有随沙筛贝数量增加而增加的趋势,这是因为成团的沙筛贝有利于小头虫和凿贝才女虫的栖息.

Mytilopsis sallei belongs to Dreissenidae, Veneroida, Bivalvia, Mollusca. Mytilopsis sallei was introduced to the Maluan Bay for the food of fish and shrimp in the early 1990s and it became the dominant species of fouling organism and it seriously affacted malacological culture. A new panel test was designed to study the quantitative relationship between Mytilopsis sallei and other macrozoobenthos outside a shrimp pond in the Maluan Bay in the summer of 2004. Results of regression analysis showed that there was negative correlation between Mytilopsis sallei and Balanus reticulatus. A high mortality of Balanus reticulatus was noted when Mytilopsis sallei was at high density（more than 10s ind./m2）. Mytilopsis sallei tended to attach to the shell of Balanus reticulatus and out-competed Balanus reticulatus for food. There were positive correlations among Mytilopsis sallei, Capitella capitata and Polydora ciliata both in the sediment and on panel, because clusters of Mytilopsis sallei were propitious to construction of soft muddy tubes by Capitella capitata and Polydora ciliata.