舟山渔场及邻近海域浮游动物数量分布特征

依据2006年8月(夏)、2007年1月(冬)、5月(春)和11月(秋)在舟山渔场及其邻近海域(29°30′-31°30′N,124°30′E以西)开展海洋生态系统综合调查时,用浅水Ⅰ型浮游生物网采集的浮游动物样本资料,分析了浮游动物总丰度及中华哲水蚤(Calanus sinicus)、精致真刺水蚤(Euchaeta concinna)、百陶箭虫(Sagitta bedoti)、肥胖箭虫(Sagitta enflata)等主要种类的数量分布和季节变化特征。结果表明:调查海域浮游动物平均丰度季节变化明显,春季(555.87ind./m3)夏季(270.87ind./m3)秋季(138.39ind./m3)冬季(127.70ind./m3);其水平分布呈现南部高、北部低的特点。中华哲水蚤为广温广盐种,春季数量最大且分布均匀,大部分海域丰度≥100.00ind./m3;夏季丰度急剧下降,主要分布在30°00′N以南海域;秋、冬季丰度较低,无明显高密集区。精致真刺水蚤为热带种,以夏、冬季丰度较高,主要分布在沿岸水与外海高盐水交汇区和调查海域的南北两端;春、秋季丰度较低且分布均匀。百陶箭虫、肥胖箭虫分别属于暖水种和热带大洋性种,冬、春季丰度都很低,无明显密集区,夏、秋季丰度较大。百陶箭虫主要分布在盐度梯度较大、外海高盐水与沿岸水的交汇区,肥胖箭虫则主要分布在外海高盐水与沿岸水交汇区的靠高温高盐水一侧,其分布与外海高温高盐水的消长有密切关系,可作为暖流指示种。温盐和水系消长变化是影响舟山渔场及邻近海域浮游动物丰度水平分布的重要因素。

Distribution characteristic of zooplankton quantitative in Zhoushan Fishing Ground and its adjacent area

Based on the data acquisitioned through the seasonal comprehensive survey of the maline ecosystem in Zhoushan Fishing Ground and its adjacent area(29 30'-31°30'N,121°30'-124°30'E)in August 2006,January,April and November 2007,which stands for summer,winter,spring and autumn respectively,this paper discussed temporal-spatial distribution of zooplankton abundance and Calanus sinicus,Euchaeta concinna,Sagitta bedoti and Sagitta enflata.The results showed that the seasonal variation in the mean abundance wag remarkable,and the order from high to low is spring (555.87 ind/m~3),summer(270.87 ind./m~3),autumn(138.39ind./m~3),and winter(127.70 ind./m~3).Calanus sinicus is eurythermal and eurysaline species,it peaked in spring and uniformly distributed,and mean abundance in most of survey areas were over 100.00 ind./m~3,It decreased dramatically in summer and mainly distributed in the area of south of 30°00'N;It was lower in autumn and winter,and there Was no dramatic high concentration districts.Euchaeta concinna is tropical species,whose abundance was higher in autumn and winter,and the concentration zone was located at the region of mixed water system;The distributable variation in the abundance was small but lower in spring and summer.Sagitta bedoti and Sagitta enflata were warm water species and oceanic water tropical species respectively,and their abundances were lower in winter and spring than those in summer and autumn.The hish distribution area of Sagitta bedoti was observed in the large of salinity gradient of converged areas of warm current and the costal water system.Hig}l abundance of Sagitta enflata region appeared in convergence region of coastal current water and off seawater, especially in the side off seawater.Because of its distribution influenced by off-sea high temperature and high salinity water masses, Sagitta enflata was a good indicator of warm current. Thermohaline and water system changes are important factors that affect the growth and decline of horizontal distribution of zooplankton abundance in Zhoushan fishing ground and its adjacent area.