Identifies carotenoids of the Thraustochytrium CHN-1 strain isolated from the Seto Inland Sea using high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry. Role of carotenoids in human nutrition; Increase in the total extractable carotenoid level with the increase in culture age; Identification of astaxanthin as the main carotenoid pigment.