两种浮游生物网捕获性能的现场测试

Field test of capture capabilities of two plankton nets

2002年10月在黄海中部选择风平浪静的天气,对长期以来在我国作为标准网具广泛使用的两种浮游生物网的捕获性能进行了现场测试。大网(锥形网型,网口直径80cm,网孔500μm)的过滤系数为0.8976±0.0578,中网(Juday网型,网口直径50cm,网孔160μm)的过滤系数为0.9857±0.0720。对于较大的浮游动物(大型桡足类、磷虾和箭虫等),两种网的捕获性能差别不甚显著。对于较小的浮游动物(小型桡足类等),差别很大。4种优势小型桡足类(Paracalanusparvus,Acartiabifilosa,Corycaeusaffinis和Oithonasimiles)种群密度之和,在中网样品中为大网样品中的164倍。由此可见,对于全面了解浮游动物种类组成和丰度仅用大网样品是不够的,中网样品是必不可少的。

The capture capabilities of two plankton nets, which have long been used as standard for zooplankton research in China, were tested in the central part of the Yellow Sea during a calm day in October 2002. The filtration efficiency of the large net(conical type, mouth diameter 80 cm, mesh size 500 μm) was 0.8976 ± 0.0578 and that of the medium net (Juday type, mouth diameter 50 cm, mesh size 160 μm) 0.9857 ± 0.0720. The difference of the capture capabilities between the two nets was not so significant for large zooplankton (large copepods, euphausiids, chaetognathes etc.). But it was great for small zooplankton (small copepods etc.). The total population density of the 4 dominant small copepods(Paracalanus parvus, Acartia bifilosa, Corycaeus affinis and Oithona similes) from the sample by medium net was 164 times the value from the sample by large net. So samples by the medium net is indispensable for an entire understanding of the zooplankton community. 