【作者】 纪炜炜；

【导师】 陈雪忠；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生态学， 2011， 博士

【摘要】 我国东海北部近海为陆架浅海区,受台湾暖流、黄东海沿岸流、长江冲淡水以及黄海冷水团综合作用,基础饵料丰富,为多种鱼类的产卵场和索饵场,是重要的海洋渔区。目前因过度捕捞、海洋环境污染等问题面临着渔业资源衰退危机。虽已采取多种养护措施并取得一定效果,但为提高管理政策的科学性和针对性,应加强东海区相关基础,为实际生产提供理论支持。本论文依据2009年夏季和2010年春季在东海北部大面积采样,以及黄海南部和长江口海域的补充采样（29°～34°N;122°～127°E）,首次利用稳定同位素分析方法对此水域内主要游泳动物营养关系进行全面系统的研究,得到以下主要结论。1.对东海最为重要的经济种类小黄鱼稳定同位素比值分析显示,小黄鱼δ¹³C比值变化范围为-20.67‰～-15.43‰,δ¹⁵N比值为9.18‰～12.23‰。δ¹³C和δ¹⁵N比值在站位间具有明显变化,其中δ¹³C变化幅度大于δ¹⁵N,跨度超过4‰。综合考虑样品体长和C/N比值因素条件下,δ¹³C比值具有显著的空间差异（P<0.001）,δ¹⁵N未显示空间差异（P=0.459）。δ¹³C比值随个体体长发生显著变化（R2=0.378,P=0.007;R2=0.584,P=0.001）。δ¹⁵N比值也随体长增加出现显著增长（R2=0.489,P=0.001;R2=0.552,P=0.001）。结果显示东海北部小黄鱼摄食策略具有高度多样性,摄食饵料复杂。2.研究水域内主要游泳动物稳定同位素比值时空分布特点显示,2009年南黄海、东海北部水域和东海中部水域的鱼类样品δ¹³C比值无显著性差异（P>0.05）。南黄海水域鱼类样品δ¹⁵N比值与其他两处相比差异显著（P<0.001）。2010年三个海域鱼类样品δ¹³C比值均有显著性差异（P<0.05）,而δ¹⁵N比值间无显著性差异（P>0.05）。此外,各海域鱼类样品存在显著的季节差异。利用稳定同位素方法划分鱼类食性类型的结果显示,2009年南黄海采集鱼类中,混合生物食性鱼类占总数的50%,浮游生物食性种类占37.5%,底栖生物食性鱼类仅占12.5%。东海北部采集鱼类中,混合食性种类占7.69%,完全底栖生物食性种类占总量的76.9%。东海中部水域采集种类中,混合食性种类占44.4%,完全底栖生物食性占55.6%。2010年结果具有一定差异。南黄海水域调查鱼类中,完全浮游生物食性仅占9.1%,混合食性种类占72.7%,完全底栖生物食性种类占18.2%。东海北部水域无完全浮游食性种类,混合食性类型占43.8%,完全底栖生物食性类型占56.3%。东海中部水域调查种类都是完全底栖生物食性。总体看来,本次研究中鱼类的主要食性类型偏底层生物,浮游生物食性种类很少。单鱼种食性类型分析结果显示,2009年夏季和2010年春季浮游生物在小黄鱼饵料中所占比例极小。2009年夏季小型鱼类如发光鲷的食物贡献率最大,为68.8%。2010年春季,神户枪乌贼为主要的食源贡献者,贡献率为56.1%。绿鳍鱼饵料食物中浮游生物的贡献率显著增多,2009年夏季和2010年春季的中值分别为5.7和1.5。底层饵料如鹰爪虾、凹管鞭虾在食源贡献占据优势地位。而神户枪乌贼贡献率中值达到45.9%,是2010年春季最大的食源贡献者。3.东海北部及邻近水域主要游泳动物（39种）稳定同位素分析表明,所有样品的δ¹⁵N值范围为6.9‰（鳀鱼）～13.4‰（带鱼）,跨度为6.5‰。δ¹³C值-20.7‰（小黄鱼）～-14.7‰（刺鲳）,跨度为6‰。各类群稳定碳氮同位素比值有显著变化（P<0.01）。线性回归分析结果表明,δ¹³C比值和个体大小之间无显著相关（ R2=0.03 , P=0.56 ）。而随着个体体长增加,δ¹⁵N比值有增加的趋势（y=0.0053x+9.987,R2=0.37,P=0.029）。6种游泳动物（鹰爪虾、戴氏赤虾、脊腹褐虾、小黄鱼、蓝圆鲹和黄鮟鱇）体长和δ¹³C比值之间存在显著相关关系。4种游泳动物（脊腹褐虾、小黄鱼、银鲳和白姑鱼）δ¹⁵N比值随体长而发生显著变化。东海北部海域主要生物资源种类的营养级处于2.50～4.01,主要集中在3.2～3.9之间。其中,营养级在2.5～3之间的生物种类占2.56%;营养级在3～3.5之间的生物种类占41.03%,以龙头鱼、鳄齿鱼、哈氏仿对虾等次级消费者为代表;营养级在3.5～4之间的生物种类占48.72%,以小黄鱼、带鱼、花斑蛇鲻、齐头鳗等杂食或肉食性鱼类为主。而营养级大于4的种类仅占7.69%,以黄鮟鱇、剑尖枪乌贼为代表。4.利用δ¹³C、δ¹⁵二维坐标多边形模型分析结果显示,2009年多边形顶点种类分别为脊腹褐虾、黄鮟鱇、剑尖枪乌贼、黄鲫、神户枪乌贼、日本须鳎、角木叶鲽。2010年模型结果显示图形中顶点种类依次为银鲳、龙头鱼、叫姑鱼、三疣梭子蟹、日本蟳、太阳强蟹和七星底灯鱼。这些生物是游泳动物群落的关键种,对于维持群落结构的稳定性具有重要作用。研究还表明,黄海南部、东海北部水域游泳动物群落的营养结构存在显著的季节差异。夏季群落营养结构的食源多样性和营养冗余度较低。5.个体大小和稳定同位素相耦合的分析结果显示,各体重等级的平均δ¹⁵N比值与体重（㏒ 2）之间存在显著的线性相关,各体重等级的平均δ¹⁵N比值与各等级物种丰富度之间也存在显著线性相关。研究水域捕食者-食物体重比为983.3:1,捕食者-食物数量比为0.33。更多还原

【Abstract】 The northern East China Sea represented one of typical shallow waters within continental shelf. It served as spawning and feeding grounds for many commercial fishes for the rich food resources brought by sea currents, including Taiwan warm current, coastal currents from the Yellow Sea and the East China Sea, freshwaters from the Changjiang River and Cold water mass in the Yellow Sea. Therefore the northern East China Sea had long been considered as important marine fishery waters in China. However, fishery resources in the area were over exploited in the recent years. Theoretic studies should be enhanced in the area to make efficient and scientific managements.The present research studied trophic structures of main nektonic organisms in the northern East China Sea, based on a large scaled collection in this area and additional samples from the southern Yellow Sea and the Changjiang River Estuary during summer 2009 and spring 2010 （29°-34°N;122°-127°E）. The results were listed as follows.1. Analysis on the isotope content of one of the most important fishes, small yellow croaker （Pseudosciaena polyatis） showed that theδ¹³C varied from -20.67‰to -15.43‰, andδ¹⁵N from 9.18‰to 12.23‰. Both of them had clear differences among different sampling stations. Bothδ¹³C andδ¹⁵N increased in line with the body length.2. Contents ofδ¹³C in fish samples from three study areas showed no clear differences （P>0.05） during 2009 cruises, whileδ¹⁵N in materials from the southern Yellow Sea showed discrepancies to the others （P<0.001）. The materials from In 2010 cruises, values ofδ¹³C in collected fish samples exhibited significant differences （P<0.05）, while there existed no difference considering those ofδ¹⁵N （P>0.05）.Contents ofδ¹³C andδ¹⁵N between cruises conducted in 2009 and 2010 at three study areas showed remarked differences (P=0.015, 0.002 forδ¹³C andδ¹⁵N in southern Yellow Sea, respectively; P<0.01 forδ¹³C andδ¹⁵N in Northern East China Sea), with the exception thatδ¹³C values in the Central East China Sea （P=0.9）.Among eight species collected from the southern Yellow Sea from 2009, three of which were identified as feeding exclusively on planktons （including Larimichthys polyactis, Harpadon nehereus and Engraulis japonicus）, four of which feeding on both plankton and benthos and the remainder only feeding on marine benthos. Fishes from the Changjiang River Estuary （13 species） could be classified into group that fed on both plankton and benthos （Pampus argenteus, Larimichthys polyactis and Champsodon capensis） and the other group fed merely on benthos （10 species in total, such as Lophius litulon, Trichiurus lepturus, Argyrosomus argentatus and Chelidonichthys kumu）. Four species from the northern East China Sea （Trachurus japonicas, Acropoma japonicum, Champsodon capensis and Saurida undosquamis） utilized both plankton and benthos as food resources, while the remainder fed only on marine benthos （a total of five species, such as Psenopsis anomala, Argyrosomus argentatus, Anago anago）.Proportions of organisms with different habits which were analyzed on the basis of materials from 2010 cruises were slightly different from those in 2009. Among organisms from the Southern Yellow Sea （11 species）, only one species feeding on plankton （Apogon lineatus）, eight species feeding on both plankton and benthos （such as Pampus argenteus, Engraulis japonicas, Trachurus japonicas and Larimichthys polyactis） and the other two species feeding merely on benthos （Johnius belengerii and Lophius litulon）. In the Changjiang River Estuary, seven species feeding both on plankton and benthos （Pampus argenteus, Engraulis japonicas, Trichiurus lepturus, Champsodon capensis and etc.）, while the other nine species feeding on benthos （such as Saurida undosquamis, Larimichthys polyactis, Lophius litulon, Chelidonichthys kumu, Rhynchoconger ectenurus, Dysomma anguillare）. Twelve species from the northern East China Sea all exclusively utilized marine benthos （including Trichiurus lepturus, Champsodon capensis, Saurida undosquamis, Dysomma anguillare, Muraenesox cinereus, Rhynchoconger ectenurus and etc.）.Both evidences from summer 2009 and spring 2010 suggested that marine planktons contributed only a small fraction of food resources for small yellow croaker. Some small sized species, such as Acropoma japonicum and Loliolus sumatrensis mainly served as food resources in 2009 and 2010 （68.8% and 56.1%, respectively）. Food resources for Chelidonichthys kumu were similar with those for small yellow croaker. The largest proportion was benthos, including Trachypenaeus curvirostris, Solenocera koelbeli and etc..3. Studies on the isotope content of the main nektonic fishes （39 species） indicated thatδ¹⁵N ranging from 6.9‰to 13.4‰, andδ¹³C from -20.7‰to -14.7‰. There existed remarked differences among individuals within species. There were present significant differences among different groups consideringδ¹³C andδ¹⁵N values （P<0.01）. Values ofδ¹³C had no clear relationships with body length after using linear regression （R2=0.03, P=0.56）, which was in contrast to that ofδ¹⁵N （y=0.0053x+9.987, R2=0.37, P=0.029）. Close correlations of body length andδ¹³C were observed in a total of six species, including Trachypenaeus curvirostris, Metapenaeopsis dalei, Crangon affinis, Larimichthys polyactis, Decapterus maruadsi and Lophius litulon. As for theδ¹⁵N values, the correlations were observed in four species, which were Crangon affinis, Larimichthys polyactis, Pampus argenteus and Argyrosomus argentatus.Trophic level for main nektonic organisms in the northern East China Sea was about the class from2.50 to 4.01, and mostly situated in the level from 3.2 to 3.9. The number of species, with which the trophic level from 2.5 to 3 accounted for the 2.56% of the total species, while those ranging from 3 to 3.5 represented the 41.03%, such as Harpadon nehereus, Champsodon capensis, Parapenaeopsis hardwickii. Species with higher trophic levels （from 3.5 to 4） in this study was about 48.72% of the total number, including Larimichthys polyactis, Trichiurus lepturus, Saurida undosquamis, Anago anago and etc.. There were also a few species with trophic level more than four in this study （represented 7.69% of total number）, i.e. Lophius litulon and Uroteuthis edulis.4. Analysis on samples collected in 2009 using“δ¹³C andδ¹⁵ two dimensional polygon”model showed Crangon affinis, Lophius litulon, Uroteuthis edulis, Setipinna taty, Loliolus sumatrensis, Paraplagusia japonica, Pleuronichthys cornutus were fringer species which suggested they played important roles in the system. Analysis on material from 2010 cruises with the same method revealed that marginal species were Benthosema pterotum, Pampus argenteus, Harpadon nehereus, Johnius belengerii, Portunus trituberculatus, Charybdis japonica, Eucrate solaris and Benthosema pterotum, respectively.5. Regression analysis showed body sizes were closely related to the averageδ¹⁵N values. The ratio of predator and food resources in the study area was 983.3. The species richness index were also related to the averageδ¹⁵N values in different size groups and the ratio of predator and food resources in the study area was 0.33.更多还原