应用稳定性同位素(δ^(13)C、δ^(15)N)技术研究长江中游干流主要鱼类的营养级

Trophic Level Analysis on Main Fish Species in the Middle Reaches of Yangtze River by δ^(13)C and δ^(15)N Analysis

应用稳定性同位素(δ13C、δ15N)技术对2011年3月至2013年12月采自长江中游干流宜昌、荆州、石首、监利、城陵矶、鄂州、九江和湖口江段的44种鱼类及3种水生无脊椎动物进行了营养级研究。长江中游干流鱼类的δ13C值范围﹣33.83‰(鳙Aristichthys nobilis)~﹣17.36‰(南方鲇Silurus meridionalis),δ15N值范围4.83‰(泥鳅Misgurnus anguillicaudatus)~15.13‰(翘嘴鲌Culter alburnus)。以梨形环棱螺(Bellamya purificata)的δ15N均值5.48‰作为营养级基准线(营养级=2),计算出该江段水生动物的营养级处于2.42~4.88,主要集中在2.83~3.61之间,鱼类平均营养级为3.28。营养级大于2.83的鱼类种类数量占了总生物种数的80.85%。大刺鳅(Mastacembelus armatus)和长春鳊(Parabramis pekinensis)营养级最低,分别为2.42±0.49和2.56±0.52,营养层级大于4.0的高级消费者为太湖新银鱼(Neosalanx taihuensis)、短颌鲚(Coilia brachygnathus)、鳙和长蛇(Saurogobio dumerili),分别为4.88±0.01、4.37±0.27、4.32±0.35和4.09±0.78,小黄黝鱼(Micropercops swinhonis)、(Elopichthys bambusa)、鳜(Siniperca chuatsi)、翘嘴鲌、青鱼(Mylopharyngodon piceus)和南方鲇的营养级分别3.99、3.92±0.16、3.89±0.27、3.87±0.62、3.59±0.69和3.59±0.57。本研究旨为长江中游渔业资源评估及其合理利用提供基础科学资料,为进一步研究长江中游干流渔业资源营养结构的动态变化及受人为活动干扰影响等提供科学参考依据。

Stable isotope analysis is commonly used to study food web structures and material flows in a wide range of aquatic ecosystems. The trophic level of 44 fish and three aquatic invertebrate species was analyzed using δ13C and δ15N analysis method（Table 1）. Samples was collected from the middle reaches of Yangtze River at Yichuang, Jingzhou, Shishou, Jianli, Chenglingji, Ezhou, Jiujiang and Hukou sections in the period of March 2011 to December 2013. In this study, there was significant difference in the δ13C and δ15N values of fishes. The value of δ13C ranged from﹣33.83‰ found in the body of fish Aristichthys nobilis to 17.36‰ in Silurus meridionalis; the value of δ15N varied from 4.83‰ in fish Misgurnus anguillicaudatus to﹣15.13‰ in speciese Culter alburnus. The average value of δ13C and δ15Ns ranged from﹣30.06‰ in Micropercops swinhonis to﹣21.24‰ in species Paramisgurnus dabryanus and from 6.91‰ in Mastacembelus armatus to 14.99‰ in Neosalanx taihuensis（Fig. 1）. Based on the δ15N values of Bellamya purificata（5.48‰） as the baseline, the trophic level of aquatic organisms was at level 2.42﹣4.88, with a concentral value at 2.83﹣3.61. While the value of the average trophic level for these fishes were at 3.28. The Trophic level around of 80.85% fish species out of the total organisms were at value 2.83. The minimal value of trophic levels were detected in species Mastacembelus armatus（2.42 ± 0.49） and Parabramis pekinensis（2.56 ± 0.52）. The trophic levels at more than 4.0 were found in species Neosalanx taihuensis（4.88 ± 0.01）, Coilia brachygnathus（4.37 ± 0.27）, Aristichthys nobilis（4.32 ± 0.35） and Saurogobio dumerili（4.09 ± 0.78）, respectively. The trophic levels values was at 3.99 for Micropercops swinhonis, 3.92 ± 0.16 for Elopichthys bambusa, 3.89 ± 0.27 for Siniperca chuatsi, 3.87 ± 0.62 for Culter alburnus, 3.59 ± 0.69 for Mylopharyngodon piceus and 3.59 ± 0.57 for Silurus meridionalis, respectively（Fig. 2）. The results of this study can provide the basic scientific data for the assessment and utilization for the fishery resources in the study area, as well as the important reference for the further studies on the dynamic structure change of fishery resources and effect of human activity disturbance in the middle reaches of Yangtze River.