Korean bullhead (Pseudobagrus fulvidraco) was collected from the Kum River areas of Kangkyung-eup, Nonsan city, Chungcheongnam-do, Korea, from April to June, 2012 and was fertilized in order to observe egg development and temperature-related cleavage rates and mitotic intervals (). The fertilized eggs were separative, demersal and light yellowish with in diameter, and did not contain oil globules. The first cleavage stages were 90 min, 80 min, 60 min and 50 min at , , and , respectively. At higher temperatures, eggs developed faster and underwent further identical development. For Korean bullhead, were min at , min at , min at and min at . There were strong negative correlations between the and water temperatures at all points studied (Y=-1.13X+58.15, =0.98, n=30, where Y is and X is temperature). The results obtained in this work will be helpful for chromosome manipulation by use of cleavage frequency data and data in Korean bullhead.

• Lim Sang Gu
• Han Hyoung Kyun
• Gil Hyun Woo
• Park In-Seok