Feeding differences of silver carp and bighead carp in the northern part of Taihu Lake：based on stable carbon and nitrogen isotope analysis
WANG Yuan1, XU Dong-po2, WANG XIAO-Lin3,SHEN Zhen-hua3,XU Pao2
1.Wuxi Fisheries College,Nanjing Agricultural University, Wuxi 214081, China; 2.Yangtze River Downstream Fisheries Resources and Environmental Science Observation Station, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences，Wuxi 214081,China; 3.Taihu Lake Fishery Management Committee of Jiangsu Province,Suzhou 215168,China
Abstract: The dynamics of δ13C and δ15N were determined in water, suspended particulate organic matter (SPM), Cyanobacteria bloom and dorsal muscles of silver carp Hypophthalmichthysmolitrix and bighead carp Aristichthysnobilissampled from Zhushan Lake, Yueliang Bay, Sanguo City and Wugui Mountain in the northern part of Taihu Lake via stable carbon and nitrogen isotope analysis technique in order to investigate feeding differences of silver carp and bighead carp in the northern part of Taihu Lake. The one-way ANOVA revealed that there were no significant difference inδ13C and δ15N values of SPM and Cyanobacteria(P>0.05), with range from 0.1‰ to 1.5‰ in δ13C and range from 0.3‰ to 1.6‰ in δ15N in SPM and Cyanobacteria，indicating that SPM was the main component in Cyanobacteria bloom. The high δ15N values (ranged from 12.8‰ to 15.8‰) of Cyanobacteria, higher than that of phytoplankton in less polluted waters (about 2‰-8‰), showed that nitrogen pollution was serious in all sampling sites. There was to some extent differences in feeding habit between silver carp and bighead carp in the four sampling sites in Taihu Lake, with significant difference in trophic levels between silver carp and bighead carp in Wugui Mountain (P<0.05) and without significant differences in other three sampling sites(P>0.05), indicating that the similar food composition (primarily of Cyanobacteria)in silver carp and bighead carp during the Cyanobacteria bloom. The silver carp and bighead carp had higher trophic levels in Yueliang Bay than those in other three waters did, which probably reveals that the two species ingest small amount of zooplankton besides Cyanobacteria, as well in Yueliang Bay. But further research is required to explain the food composition specifically. The findings showed that SPM was the main food sources of silver carp and bighead carp in the northern part of Taihu Lake. However, Cyanobacteria was the main component of SPM, and provide a new basis for algal control and sustainable utilization of algae in waters by silver carp and bighead carp.
王媛, 徐东坡, 王小林, 沈振华, 徐跑. 基于碳氮稳定同位素技术探究太湖北部湖区鲢、鳙食性差异[J]. 大连海洋大学学报, 2017, 32(5): 597-602.
WANG Yuan, XU Dong-po, WANG XIAO-Lin, SHEN Zhen-hua, XU Pao. Feeding differences of silver carp and bighead carp in the northern part of Taihu Lake：based on stable carbon and nitrogen isotope analysis. Journal of Dalian Ocean University, 2017, 32(5): 597-602.
2017, Vol. 32 
