长江口及其邻近海域鱼类群落结构分析

IOCAS-IR > 海洋环流与波动重点实验室

	长江口及其邻近海域鱼类群落结构分析
其他题名	Fish community structure in the Changjiang Estuary and adjacent waters
	于海成
学位类型	博士
	2008-06-12
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	鱼类群落结构环境因子多元分析长江口
摘要	根据长江口及其邻近海域鱼类群落的历史调查资料，综合运用主成分分析(PCA)、无偏对应分析(DCA)和典范对应分析(CCA)等群落排序方法，以及双向指示种分析(TWINSPAN)等数量分类方法，分析了1998-2004年长江口鱼类群落结构，以及其相关环境因子的变化特征。从群落和环境两方面，分别探讨了其空间分布、时间动态和季节变化的特征，并着重讨论了环境因子对群落特征的影响程度。结果表明：在空间分布上，自近岸到外海的水深、盐度、浊度、透明度、营养盐和悬浮物这一综合梯度，与鱼类丰度关系最密切。近岸区以营养盐丰富、初级生产力高等特点，为近岸的广盐性和半咸水鱼类提供了充足的食物来源；以高浊度和高溶解氧浓度，提供了良好的庇护所。外海区鱼类种类丰富，但丰度较低。南北方向上大致以31°30′N为界，鱼类群聚在特定季节表现出明显的空间分化。在时间动态上，1998-2004年长江口及邻近海域生态环境的改变，驱动了鱼类群落的演替，具体表现为：三峡水库蓄水前，群落主控因子为水深、底层水温和底层溶解氧，蓄水后主控因子为表底层pH值、表层温度和表层溶解氧；蓄水后冲淡水量的减少导致海域内盐度升高，悬浮物的减少改善了浮游植物生长的光照条件；与此相关，春季和秋季鱼类群聚均发生了显著变化，海洋性鱼类和浮游生物食性鱼类在群落中比重分别有所增加。在季节变化上，冬季环境以低水温、高溶解氧为突出特点，夏季则反之；春季表层pH值显著高于其他季节，而表底层温度与秋季相比偏低；秋季环境条件接近中等水平。受此影响，鱼类群落发生明显的季节性演替，主要表现为鱼类丰度的波动、物种组成和优势种组成的更替，以及各功能群相对比例的此消彼长。
其他摘要	The characteristics of the fish assemblage and the influences of environmental factors in the Changjiang Estuary and adjacent waters were studied based on fish abundance data sampled from 1998 to 2004. Multivariate methods were adopted, including community ordination such as principal components analysis (PCA), detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA), and two-ways indicator species analysis (TWINSPAN). Biological community structure and environmental factors were analyzed respectively to reveal their spatial distributions, temporal dynamics and seasonal variations. The influence degree of environmental factors on the fish community was especially discussed. The analyses results showed: Environmental factors including water depth, salinity, turbidity, transparency, nutrient and suspending matters, which formed a synthetic spatial gradient from coastal to pelagic area, were the most related to fish abundance. Higher nutrient concentration and primary productivity provided plenty of food to euryhaline and brackish-water fishes, and higher turbidity as well as dissolved oxygen made it good refuge for the fishes. Fishes in pelagic area were richer in species diversity but less abundant. The characteristics of the fish assemblages in southern and northern Changjiang Estuary were distinguished in certain seasons, and the borderline was approximately 31°30′N. Ecological and environmental factors temporally changed from 1998 to 2004, and drove the fish community succession. Before the first impoundment of the Three-Gorges Reservoir in June 2003, environmental factors influencing the fish community included water depth, bottom temperature and bottom dissolved oxygen, while those after the first impoundment included bottom and surface pH, surface temperature and surface dissolved oxygen. The water-retaining in the reservoir reduced fresh water input into the estuary, and caused the increase of salinity. A great amount of sands had sedimentated in the reservoir, and the total suspending matters in the estuary were decreased, which made the illuminative condition for phytoplankton growth improved. In correspondence, fish assemblage characteristics in both May and November had changed significantly, while marine and planktivorous fish became relatively more important in fish assemblages. Environmental factors in winter were characterized by low temperature and high dissolve oxygen concentration, while those in summer were opposite. Surface pH in spring is significantly higher than that in other seasons and temperature lower than that in autumn. Environment conditions in autumn were close to the average value of the each factor. The resultant seasonal succession happened in fish community, which appeared in fluctuation of fish abundance, replacement in species composition and dominant species, as well as periodical rise or fall in the abundance proportions of the functional groups.
页数	87
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/959
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	于海成. 长江口及其邻近海域鱼类群落结构分析[D]. 海洋研究所. 中国科学院海洋研究所,2008.

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