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2008年度鱼类监测报告(摘要)
作者:    点击次数:10119    发布时间:2009-10-19      【字体:
 

 

2008年,我们开展了崇明东滩保护区潮间带潮沟鱼类的空间分布和时间动态调查。捕获的潮沟鱼类主要为海洋或淡水洄游种及河口定居种,包括花鲈、鮻、刀鲚等重要经济鱼类物种,且大多为幼鱼,表明盐沼潮沟是这些鱼类的重要索饵育幼场所,而河口盐沼生态系统对于洄游鱼类和渔业经济具有重要意义。

在空间分布上,于20085月和12月在南、北、东部共7条潮间带潮沟开展了调查。调查采用插网,在大潮期间分别采集日潮和夜潮样品,共计97网次。共捕获鱼类1234种,其中虾虎鱼科鱼类个体数最多,鲤科鱼类次之,其它科较少。就生态类群而言,海洋洄游种个体数最多,占总捕获鱼类个体数68.08 %,河口定居种次之,占27.33 %;但河口定居种生物量最高,总计9893.00 g,海洋洄游种次之,为6993.21 g5月的鱼类种类、个体数、生物量及各优势种的个体数和生物量均显著高于12月。5月,15号潮沟中的鱼类总生物量一般显著高于67号潮沟。12月,鱼类的总生物量在7条潮沟间无显著差异。花鲈和斑尾刺虾虎鱼在南部淡水潮沟最多,但其它优势鱼类如阿部鲻虾虎鱼、大弹涂鱼、大鳍弹涂鱼、拉氏狼牙虾虎鱼、纹缟虾虎鱼、弹涂鱼等较偏好盐度较高的潮沟水体。鱼类群落结构在南部淡水潮沟(57号潮沟)与盐度较高的东部、北部潮沟(14号潮沟)间有明显区别,而这种差异在丰水期尤其明显。可见,潮沟鱼类的分布与盐度十分相关。

在时间动态调查过程中,我们选取了崇明东滩南部团结沙的2条潮间带潮沟,在每条潮沟入口处各设置1顶插网。采样时间为20083月至20092月,每月大、小潮各连续采样3天,每天分别收集日潮和夜潮样品,共计248网次。周年监测共捕获鱼类101169条,63195 g,隶属于2057种。就物种数而言,一般大潮期间捕获鱼类物种数大于小潮期间,个别月份(7月、9月)则相反。捕获潮沟鱼类个体数在510月期间较多,于7月出现峰值。510月,每月小潮期间捕获的鱼类个体数多于该月大潮期间的捕获数;在其它月份,则表现为大潮期间鱼类个体数多于该月小潮期间捕获个体数。潮沟鱼类的个体数、物种数和生物量的季节差异和昼夜差异均显著,夏、秋季节的鱼类种类数和生物量显著高于春季和冬季,夏季的鱼类个体数显著多于其它三个季节,可见夏秋季是鱼类利用盐沼潮沟的主要季节。夜潮的鱼类数量显著高于日潮,显示夜间是鱼类利用盐沼的主要时间。

Abstract

In 2008, the spatial and temporal variations of fish community in intertidal creeks in Chongming Dongtan Nature Reserve were investigated. The fish community was dominated by juvenile individuals of marine/freshwater migrants and estuarine residents, including economically important fish species such as Lateolabrax maculates, Chelon haematocheilus and Coilia nasus. This indicates that the salt marshes of Dongming Dongtan may play important roles for nursing fish community and for sustaining fishery.

During the spatial surveys, 7 intertidal creeks located at northern, eastern and southern parts of Dongtan were investigated in May and December of 2008. By using fyke nets, a total of 97 fish samplings were conducted by consecutive day and night during the spring tides. A total 12 families and 34 species were documented, and the most individually abundant family was Gobiidae, followed by Cyprinidae. Most abundant ecological groups were marine migrants and estuarine residents, each accounting for 68.08 % and 27.33 % of the total catch. The biomass of estuarine residents and marine migrants caught were 9893.00 g and 6993.21 g, respectively. In May, species richness, abundance and biomass of the fishes caught, abundance and biomass of dominant fishes were all significantly higher than those in December. In May, fish biomass from Creek 1 to Creek 5 was significantly higher than those from Creeks 6 and 7. In December, fish biomass was not significantly different among 7 sampled creeks. Spatially, Lateolabrax maculates and Acanthogobius ommaturus tended to be most abundant in the southern freshwater creeks, while other dominant fish species such Mugilogobius abei, Boleophthalmus pectinirostris, Periophthalmus magnuspinnatus, Odontamblyopus lacepedii, Tridentiger trigonocephalus, Periophthalmus modestus prefer creeks of higher salinity. The community structures of fish from the southern freshwater creeks (Creek 5-7) were clearly separated from those from the northern and eastern creeks (Creeks 1-4), especially in flood season. This indicates that the salinity was an important factor structuring the intertidal fish communities.

The temporal variations of fish utilization of the marsh intertidal creek at Dongtan were studied based on surveys from March 2008 to February 2009. Two creeks at Tuanjiesha of Chongming Dongtan were investigated by using fyke nets. In each month, 3 consecutive day and night samplings were taken during both spring tide and neap tide, yielding 248 fish samplings during the study. A total of 101169 individuals and 63195 g fish were caught, belonging to 20 families and 57 species. With the exception of July and September, the fish species richness during the neap tide was generally greater than that of the spring tide of the month. Fish abundance was highest during May to October, peaking in July. During May to October, the fishes caught during the neap tide were numerically more than that caught during the spring tide of the month. However, it was the opposite in other months. The seasonal variations and diel periodicity of fish abundance, species richness and biomass were all evident. The fish species richness and biomass in summer and fall were significantly higher than in spring and winter. Numerically, the fish abundance in summer was the highest among all seasons. The night samplings yielded more fishes than the day samplings. These findings indicate that the fishes utilize intertidal creeks of estuarine marshes mainly during summer and fall and at night time.