楚科奇海和白令海毛颚类的分布

DISTRIBUTION OF CHAETOGNATHA IN CHUKCHI SEA AND BERING SEA

根据 1 997年 7─ 8月我国首次北极科学考察期间 ,分别在楚科奇海和白令海进行海洋综合调查的资料 ,分析了这两区毛颚类种类组成和生态类型的特征、丰度的水平分布、层状分布和昼夜垂直分布。同时还就其数量分布与某些环境因子的相关性进行初步探讨。研究表明 :( 1 )两区共记录毛颚类 7种 ,可分为 3个类群 ,在数量上 ,白令海的个体数明显高于楚科奇海 ;其平面分布的状况主要由优势种所左右 ,并且都呈现出南高北低的分布格局。 ( 2 )在楚科奇海 ,毛颚类的层状分布以 5 0─ 2 0 0m层数量较高 ,5 0 0─ 80 0m层最低。白令海毛颚类的昼夜垂直分布的趋势是 ,白天总个体数最高比值均出现在 2 0 0─ 5 0 0m层 ,而晚上─凌晨则密集于 1 0 0m以浅水域 ,尤以 0─ 5 0m层数量最高 ,表现出白天下降夜晚上升的分布规律。

The data used in this paper was obtained from the comprehensive oceanographic survey during the First Chinese National Arctic Research Expedition in Chukchi Sea and Bering Sea in July and August 1999. The characteristics of ecological groups, species composition, horizontal and vertical distribution of Chaetognatha in both Chukchi Sea and Bering Sea are described and the relationships of Chaetognatha density and some other environmental factors are discussed. The results show that seven species of Chaetognatha were recorded which belongs to 3 ecological groups. The number of Chaetognatha was higher in Bering Sea than in Chukchi Sea. The density of dominant species determined the total Chaetognatha abundance and it was higher in south than in north. The density was high in water layer of 50-200m and low in water layer of 500 -800m in Chukchi Sea. In the other hand, the density was comparatively high in layers of 200-500m in Bering Sea during the daytime and aggregated in water layers 0-100m, particularly in 0-50m during the night, showing a pattern of up and down migrations in day and night, respectively.