Abstract: This paper investigated the morphological character, framework, and fecundity of Odontobutis obscura in Huaihe River water system, aimed to provide references for the morpholog-ical germplasm criteria and phylogenesis study of the fish. The results showed that in countable characters, the O. obscura in the water system had dorsal fin (D) Ⅶ, Ⅰ-9-10, caudal fin (C) 14-15, anal fin (A)Ⅰ-7-8, ventral fin (V) Ⅰ-5, pectoral fin (P) 14-15 rays, longitudinal scales 36-41, transversal scales 14-18, scales on lateral sensory papillae line 28-30, gill rakes on first gill arch 9-11, and vertebras 2829. In measurable characters, the total length was 1,23 times of body width, and body length was 3.82 times of body width, 3.08 times of head length, 5.19 times of caudal peduncle length, 1.86 times of alimentary canal length, and 6.99 times of intestine length. The head length was 2.94 times of snout length, 6.09 times of eye diameter,3.86 times of interorbital distance, and 1.94 times of mouth breadth. Body length was 0.96 times of body breadth, and caudal peduncle length was 1.66 times of caudle peduncle width. The fatness index was 2.90. On average, the absolute fecundity, relative fecundity to body length, and relative fecundity to body mass were 3 288 eggs, 308.7 eggs·cm^-1, and 102.3 eggs·g^-1, and the maturity indices for female and male were 12.87% and 1.13%, respectively.

Key words: Changjiang River estuary, Adjacent sea areas, Red tides, Environmental characteristics