The species number of Crustacea obviously decreased from 7 to 1,and that of Polychaeta decreased from 4 to 3 disappeared at last.

• 总趋势是 ,围垦以后 ,甲壳动物种类明显减少 ,由 7种减少到 1种 ; 随着围垦时间延长 ,多毛类种类减少 ,由 4种减少到 3种 ,直到最后消失 ;