Growth and food availability of silver and bighead carps: evidence from stable isotope and gut content analysis |
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Authors: | Qiong Zhou,Ping Xie,Jun Xu,Zhixin Ke,& Longgen Guo |
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Affiliation: | Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; Graduate School of the Chinese Academy of Sciences, Beijing, China; South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China |
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Abstract: | A 2-year investigation of growth and food availability of silver carp and bighead was carried out using stable isotope and gut content analysis in a large pen in Meiliang Bay of Lake Taihu, China. Both silver carp and bighead exhibited significantly higher δ13C in 2005 than in 2004, which can probably be attributed to two factors: (i) the difference between isotopic compositions at the base of the pelagic food web and (ii) the difference between the compositions of prey items and stable isotopes. The significantly positive correlations between body length, body weight and stable isotope ratios indicated that isotopic changes in silver carp and bighead resulted from the accumulation of biomass concomitant with rapid growth. Because of the drastic decrease in zooplankton in the diet in 2005, silver carp and bighead grew faster in 2004 than in 2005. Bighead carp showed a lower trophic level than silver carp in 2005 as indicated by stable nitrogen isotope ratios, which was possibly explained by the interspecific difference between the prey species and the food quality of silver carp and bighead. |
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Keywords: | silver carp bighead carp stable isotope gut content growth food availability |
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