First record of the non-native jellyfish Chrysaora pacifica (Goette, 1886) (Cnidaria, Scyphozoa) in Liaodong Bay, Bohai Sea, China

The occurrence of Chrysaora pacifica (Goette, 1886) (Cnidaria, Scyphozoa) is reported from most Japanese and Korean coastal waters. This is the first record of the alien jellyfish Chrysaora pacifica from the Liaodong Bay, Bohai Sea, China. Eight specimens of Chrysaora sp. were collected. Based on the evidence from morphology (bell, size, umbrella pattern, number of tentacles, and lappets) and further molecular analysis (mitochondrial DNA sequences comparison), we identified the Chrysaora sp. jellyfish as Chrysaora pacifica which belonged to Cnidaria, Scyphozoa. The distribution of C. pacifica in the Bohai Sea is currently unknown, however, there is a high potential risk for the spread of this species to the whole Bohai Sea by the ocean currents circulation system. As C. pacifica is a bloom-forming species, we recommend further work to assess the distribution of this species and its impact on the local fauna and flora.