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Lake Taihu is a large, shallow, and eutrophic lake in China. It has provided local communities with valuable fisheries for centuries, but little is known of the trophodynamics, or of its faunal communities. Carbon and nitrogen isotopic composition was used to assess its trophic pathways and the food web structure [food sources and trophic levels (TL)]. Basal food sources were distinguishable based on their d 13 C values, ranging from -27.2 to -15.2%. Consumers were also well separated in d 13 C (-26.9 to -17.9% for invertebrates and -25.7 to -18.1% for fishes), which allowed for an effective discrimination of carbon sources between these fauna. An average trophic enrichment factor of 3.4% was used to calculate the TLs based on d 15 N of zooplankton, with results indicating a food web having four TLs. Although d 15 N values overlap and cover a large range within trophic compartments, the isotopic signatures of the species assessed revealed a general trend of 15 N enrichment with increasing TL. Stable isotope signatures were also used to establish a general food web scheme in which five main trophic pathways were analyzed.

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