| 引用本文: | 宁加佳,杜飞雁,王雪辉,王亮根,谷阳光,李亚芳.南沙群岛西南部陆架区底层鱼类营养结构研究.海洋与湖沼,2016,47(2):468-475. |
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| 南沙群岛西南部陆架区底层鱼类营养结构研究 |
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宁加佳,杜飞雁,王雪辉,王亮根,谷阳光,李亚芳
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中国水产科学研究院南海水产研究所 广东省渔业生态环境重点实验室 农业部南海渔业资源环境科学观测实验站 农业部南海渔业资源开发利用重点实验室 广州 510300
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| 摘要: |
| 为了解南沙群岛西南部陆架区底层鱼类食物网的营养结构特征, 于2013年9月利用稳定同位素方法分析了24种底层鱼类的碳和氮稳定同位素比值(δ13C和δ15N值), 并计算了基于δ13C-δ15N量化的6个营养结构的群落范围指标。结果显示: 南沙群岛西南部陆架区底层鱼类的δ13C值在-20.4‰- -17.0‰之间, 均值为(-19.1±0.8)‰; δ15N值的范围为7.9‰-12.2‰, 均值为(9.7±1.0)‰。鱼类的营养位置在3.06-4.33之间, 平均值为3.58±0.29, 表明均以肉食性为主。根据群落范围指标结果分析, 鱼类群落的δ13C和δ15N值范围(CR和NR)分别为3.4和4.3, 表明南沙群岛西南陆架区底层鱼类的初始食源较为单一, 营养层次较少; 总面积(TA)和到重心的平均距离(CD)分别为5.8和1.0, 意味着鱼类食物网营养级多样性的总程度和平均程度均较低; 平均最近相邻距离(NND)及最近相邻距离的标准偏差(SDNND)分别为0.37和0.43, 说明研究海域底层鱼类食物网的营养冗余程度较高, 不同种类之间的营养生态位幅宽较小, 重叠程度较高。此外, 浅海长尾鲨(Alopias pelagicus)和狐形长尾鲨(Alopias vulpinus)在南沙群岛西南部陆架区底层鱼类群落的营养结构中起着重要作用。因此在对该海域渔业资源进行开发利用时, 应禁止捕捞这些种类, 而对一些冗余种类, 如多齿蛇鲻(Saurida tumbil)、条尾鲱鲤(Upeneus bensasi)和带鱼(Trichiurus haumela)等, 可以适度捕捞, 以维持底层鱼类群落营养结构的完整性, 在渔业资源合理开发、持续利用的同时, 有效地保护海洋生态系统的安全发展。 |
| 关键词: 南沙群岛西南部陆架区 营养结构 碳和氮稳定同位素 群落范围指标 底层鱼类 |
| DOI：10.11693/hyhz20151100282 |
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| 基金项目:广东省自然科学基金资助项目, 2014A030310232号; 中央级公益性科研院所基本科研业务费专项资金(中国水产科学研究院南海水产研究所)资助项目, 2014TS02号; 国家科技支撑计划课题, 2013BAD13B06号; 广东省省级科技计划项目, 2014A020217011号; 农业部财政重大专项, NFZX2013号。 |
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| THE TROPHIC STRUCTURE OF DEMERSAL FISH SPECIES IN SOUTHWESTERN CONTINENTAL SHELF OF NANSHA ISLANDS, SOUTH CHINA SEA |
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NING Jia-Jia1,2,3,4,5, DU Fei-Yan1,2,3,4,5, WANG Xue-Hui1,2,3,4,5, WANG Liang-Gen1,2,3,4,5, GU Yang-Guang1,2,3,4,5, LI Ya-Fang1,2,3,4,5
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1.South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences;2.Guangdong Provincial Key Laboratory of Fishery Ecology and Environment;3.Scientific Observing and Experimental Station of South China Sea Fishery Resources and Environments, Ministry of Agriculture;4.Key Laboratory of South China Sea Fishery Resources Development and Utilization, Ministry of Agriculture;5.Guangzhou 510300, China
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| Abstract: |
| We investigated carbon and nitrogen stable isotope ratios (δ13C and δ15N) of demersal fish species collected in September 2013 in southwestern continental shelf of Nansha Islands, South China Sea by trawling (the net was 92m long, perimeter 128m, floating line 49m, lead line 59m, mesh size 50mm, trawling time 1h at 3kn/h) to study the trophic structure of the fish species. Several quantitative metrics based on the δ13C and δ15N ratios were calculated to quantitatively characterize the trophic structure in community-wide aspect. The results show that, the average δ13C and δ15N values of the demersal fish species in the study region were (-19.1±0.8)‰ and (9.7±1.0)‰, in range of -20.4‰- -17.0‰ and 7.9‰- 12.2‰, respectively. The average trophic position was 3.58±0.29 and ranged in 3.06-4.33, indicating that these demersal fish species were mostly carnivorous. δ13C range and δ15N range values based on the quantitative metrics were 3.4 and 4.3 respectively, suggesting a few basal resources in low trophic level of the fish food web in the study area. Total area and mean distance to centroid values were 5.8 and 1.0 respectively, indicating that the overall and average degree of trophic diversity were low. Mean nearest neighbor distance and standard deviation of nearest neighbor distance values were 0.37 and 0.43 respectively, suggesting that the fish food web in this study area has high trophic redundancy, small trophic niche width as well as low degree of trophic niche separation. In addition, fish species Alopias vulpinus and Alopias pelagicus played an important role in trophic structure of fish community of this area. To maintain the integrity of the trophic structure, ensure the sustainable use of fishery resources, and protect marine ecosystem, we recommend forbidding the capture of these two species and moderately fishing some redundant species (Saurida tumbil, Upeneus bensasi, Trichiurus haumela, etc.). |
| Key words: southwestern continental shelf of Nansha Islands trophic structure carbon and nitrogen stable isotopes community-wide metrics demersal fish |
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