Pacific abalone Haliotis discus hannai (Ino, 1953) aquaculture is a thriving and prosperous industry in China, producing more than 110,000 metric tons in 2013. In recent years, Fujian in the southern region of China has become the chief abalone farming center, accounting for 85% of the total Pacific abalone yield. The practice of transferring abalone to northern regions to oversummer emerged because of challenges in Fujian, such as fouling, high temperature stress, and unexpected extreme weather events. From the view of ecology and conservation biology, however, the potential ecological risks of this practice should be considered as the abalone shells could act as vectors of exotic organisms. In this study, oyster samples from the shells of live, farmed abalones were collected in Fujian in southern and Rongcheng in northern China. The oysters were identified using a recently developed molecular method. In addition, the fouling oysters on Pacific abalone transferred to the northern region were monitored in a field trial. Survivorship and growth performance of the fouling oysters on the transferred abalones were determined through investigation of digital images taken at 2-wk intervals during the oversummering period. Results of the molecular analysis showed that fouling oysters collected from southern and northern regions are Crassostrea angulata and Crassostrea gigas, respectively. The field trial demonstrated that approximately half of the C. angulata, from the southern region, were still alive after a 6-mo oversummering period in the northern region. Findings from this study have important implications for aquaculture, the management and monitoring of cultured populations of Pacific abalone, and the conservation of wild oyster species in China.