辽东湾北部近海大型水母数量分布和温度盐度特征

摘要

The distribution of giant jellyfish and the ecological type were analyzed on the basis of the sampling data obtained during the surveys in inshore waters within 10m isobath of the northern Liaodong Bay, Bohai Sea from late May to late July from 2009 to 2011. There were four main species of giant jellyfish, Rhopilema esculentum, Nemopilema no- mural, Cyanea nozakii and Aurelia sp.1. The larval medusae of R. esculentum was mainly found within 5m isobath in coastal estuaries of the northern Liaodong Bay, and adult medusae was mainly found in both sides of the waters near 5m isobath. The adult had a slightly tendency to go to deep waters or low jellyfish catch density waters with the individual increasing. The relatively high temperature and low salinity area of coastal estuaries was an optimum environment for the growth of R. esculentum. There were a large amount of larval medusae of N. nomurai in inshore waters of northern Liaodong Bay in June, and the amount ofN. nomurai decreased a lot with the individual increasing in the area in July. Au- relia sp.1 mainly inhabitated in the southern Liaodong Bay, and was found a few in inshore waters of the northern Liaodong Bay in 2010 and 2011. C. nozakii inhabitated in high salinity area, and was few found in Liaodong Bay in recent years. Among giant jelly- fishes in Liaodong Bay, N. nomurai grew more quickly. The occurrence time of the larval medusa ofR. esculentum and N. nomurai in Liaodong Bay was later than in the Yellow Sea and East China Sea.%通过2009--2011年5月下旬-7月下旬辽东湾北部近海10m等深线内的大型水母调查数据．分析了辽东湾北部近海近三年中大型水母资源状况，并探讨了辽东湾大型水母的生态类型。结果显示：辽东湾北部近海大型水母种类主要有海蜇（Rhopilema esculentum）、沙蜇（Nemopilema nomurai）、白色霞水母（Cyaneanozakii）、海月水母（Aureliasp．1），海蜇和沙蜇是优势种。海蜇幼水母阶段主要集中分布在5m等深线以内的近岸河口水域，随着个体增大有略向深水或密度较小的水域扩散的趋势，仍主要分布在5m等深线两侧水域，属于高温低盐种类。6月份调查海区中发现大量的沙蜇幼水母．随着沙蜇个体增大，7月份调查海区中沙蜇数量大幅度减少。辽东湾海月水母在南部海域出现较多，2010、2011年在北部近海部分海域出现。白色霞水母近几年来辽东湾出现较少，栖息在盐度较高的水域。辽东湾各种大型水母中，沙蜇的生长速度最快。辽东湾海蜇幼水母、沙蜇幼水母的海区出现时间要晚于黄、东海。