Samples of were collected from the northern South China Sea from July 2014 to May 2015. Biocharacters such as fork length (FL), body weight (BW), maturity stage, and otolith daily incrementation were measured and compared to understand the differences between the two species. Differences in the FL and BW of between females and males were significant (K, and were 109-310 mm and 117-283 mm, 13-358 g and 20-297 g, 76-558 d and 73-526 d, 278 mm and 276 mm, 1.30 and 1.30, -0.07 a and -0.08 a, respectively. The youngest age group of female at maturity stage Ⅲ was 350-400 d, and the hatching of female and male samples primarily occurred in March, July, and September to October. The FL range, BW range, otolith age, S. undosquamis were 105-269 mm and 95-264 mm, 11-220 g and 8-228 g, 79-486 d and 84-488 d, 269 mm and 265 mm, 1.29 and 1.29, -0.06 a and -0.06 a, respectively. The youngest age group of female at maturity stage Ⅲ was 200-250 d, and the hatching of female and male samples primarily occurred from June to November. For decades, the size and age of maturity of have been decreasing. Taken together, a policy that decreases fishing pressure could help to achieve the sustained development of the fishery resources of in the South China Sea.