Northernmost record of half-fringelip mullet, Crenimugil heterocheilos (Bleeker, 1885) (Teleostei: Mugilidae), from the Okinawa-jima Island, Ryukyu Archipelago, southern Japan.

Two specimens (109.5, 158.3 mm in standard length) of the half-fringelip mullet, Crenimugil heterocheilos (Bleeker, 1885) (Teleostei: Mugilidae), were collected from a river in northern Okinawa-jima Island, Ryukyu Archipelago, southern Japan, on March 20, 2017 and March 22, 2018. These two specimens represent the first record of C. heterocheilos from Okinawa-jima Island and extends the known range of the species approximately 500 km north-eastward from its previously recorded northernmost range. The specimens collected from Okinawa-jima Island are considered to have been transported by the Kuroshio current in an early life stage (egg / larva) from a region to the southwest. Following a year of monthly underwater visual census surveys, C. heterocheilos was confirmed to overwinter in the river on Okinawa-jima Island. [ABSTRACT FROM AUTHOR]