前言北部湾为半封闭海区,北、东、西三面靠陆,南面与南海相连,湾东尚有琼州海域与广州湾相通,湾内深度等值线的分布趋势大致与海岸平行,海底地形由北向南倾斜,深度沿岸较浅,向湾口逐渐加深。该研究海区是深度小于90米的大陆架浅海(见图1)。北部湾的这 Foreword Beibu Bay is a semi-enclosed sea area, with land on the three sides of North, East and West, connected to the South China Sea in the south, Qiongzhou Sea Bay in the east of the Bay and the bay of Guangzhou. The distribution of the depth contours in the Bay is roughly parallel to the coastline. South slope, the depth of the shallow coast, gradually deepening to the mouth. The study area is shallow continental shelf (see Figure 1) less than 90 meters deep. This North Bay