Using Sr isotopes to trace the geographic origins of Chinese mitten crabs

Identifying the geographic origins of Chinese mitten crabs is important for food safety and fair market competition. In this study, we used strontium (Sr) isotopes as a tool to trace the geographic origins of Chinese mitten crabs. Chinese mitten crabs, water, and different types of crab feed were collected from four different lakes for Sr isotope analyses. The results showed that the Sr isotope compositions of the different parts from one single crab were consistent within error, indicating that any piece of a crab could be used to represent the Sr isotope characteristics of the whole crab. The Sr isotope compositions of Chinese mitten crabs from the same lake were consistent within the analytical error, and the values were similar to the Sr isotope composition of the water from the same lake. However, the Sr isotope compositions of water and crabs from different lakes are significantly different. Therefore, the Sr isotope compositions of Chinese mitten crabs are mainly controlled by lake water composition, while the impact of feed is limited. This study provides an effective method for tracing the geographic origins of Chinese mitten crabs.