不同孔径底层筛对胶州湾大型底栖动物取样结果的影响

利用2003年11月在胶州湾所设的20个站，每站成功取4个定量采泥样品，每两个样品分别用底层筛孔径0．5mm和1．0mm的套筛冲洗所得的大型底栖动物样品，进行大型底栖动物栖息密度、生物量及种数比较分析。结果显示，0．5mm孔径底层筛样品的总平均栖息密度、总平均生物量、总种数分别是1．0mm底层筛的样品的1．36，1．19，1．15倍；两种筛所获的样品对大型底栖动物的栖息密度影响最明显，对生物量、种数影响较小；环节动物多毛类、甲壳动物类群中的钩虾类个体较细小，是受底层筛孔径影响最明显的类群；0．5mm孔径底层筛的取样质量明显好于1．0mm孔径底层筛。

Comparison of sampling results of macrobenthos using different apertures of sampling sieve in Jiaozhou Bay

Based on the macrobenthic samples collected in November, 2003 from 20 sampling stations in Jiaozhou Bay, Shandong, with 0. 5 and 1.0 mm aperture sampling sieves respectively, the sampling data were compared and analyzed. The results show that the total mean abundance, total mean biomass and total number of species collected by the 0. 5 mm aperture sampling sieve are 1. 36, 1. 19 and 1. 15 times as those by the 1.0 mm aperture sampling sieve respectively. The influence made by the two kinds of sampling methods on the abundance of macrobenthos is distinct, The influence on the biomass and number of species is not noticeable. Because the body sizes of polychaetes and gammaridean crustaceans are small, the differences of abundance and biomass of these groups measured by the two sampling methods are distinct, there are not significant differences of other macrobenthic groups collected by the two methods. The 0.5 mm aperture sampling sieve is better than 1.0 mm aperture sampling soieve in macrobenthic collection.