Stable carbon and nitrogen isotopes were used to investigate nutrient pathways and trophic relationships from the rice-crab system in Panjin,Liaoning Province,China. Values of δ 13 C ranged from-27.38‰±0.44‰ to-18.34‰±0.26‰ and δ 15 N ranged from 1.10‰±0.88‰ to 9.33‰±0.57‰. Pseudorasbora parva(Stone moroko) had the highest δ 13 C and δ 15 N values. The lowest δ 13 C values were obtained for the macrophytes and the lowest δ 15 N value was found in sediments. Stable carbon and nitrogen isotopes were used to determine the contribution of different food items to the diets of crabs. The δ 13 C results indicated that the P seudorasbora parva made the greatest contribution to the diet of E riocheir sinensis(Chinese mitten crab),while the δ 15 N results indicated that most food items contributed more than 10% to the diet of the crab. There were three trophic levels identified in the system(Levels 0–2). The crab Eriocheir sinensis,fish Pseudorasbora parva and Misgurnus anguillicaudatus(Oriental weatherfish),and the oligochaete L imnodrilus hoffmeisteri(Limnodrilus worm),were at the second level,zooplankton were at the first level and suspended particulate matter and macrophytes were at trophic position 0. 相似文献