Abstract: Pseudocrossocheilus tridentris, from the Labeoninae subfamily, is an indigenous fish species in China. In this study, 206 individuals of P. tridentris were collected during the spring, summer, and autumn of 2019 from Mabie River, a primary tributary of the Nanpanjiang River. We examined the sex ratios, gonad development, gonadosomatic index, size at sexual maturity, egg size, and fecundity of the species. The results showed that the ratio of male to female was close to 1∶1 (P>0.05). Matured females were consistently observed throughout the survey period. The majority (over 80%) reached sexual maturity from April to June, exhibiting a significantly higher gonadosomatic index compared to other sampling months (P<0.05). Logistic regression analysis revealed the sizes at first sexual maturity (SL₅₀) for females and males was 136.5 mm and 134.3 mm, respectively. The mean absolute fecundity and relative fecundity of P. tridentris was 1039 eggs per female and 18 eggs per gram, respectively. Absolute fecundity was positively correlated with body length and net weight. The frequency distributions of egg diameter for stages III, IV, and V showed unimodal patterns, suggesting a single-batch spawning strategy. P. tridentris is characterized as a typical opportunist, displaying sexual maturity at a small body size, relatively low absolute fecundity, and a single-batch spawning strategy. The results could provide foundational data for the conservation of P. tridentris and artificial reproduction efforts.

Key words: Pseudocrossocheilus tridentris, reproductive biology, fecundity, gonadosomatic index