Objective In recent years, as the encroachment of non-native species continues to expand, the native Viviparidae populations have faced significant threats, immediate action is needed for genetic conservation and commercial cultivation. The challenge lies in the lack of distinct sexual dimorphism in the shells of these freshwater snails, which complicates the rapid and accurate determination of gender—a critical aspect of successful breeding programs. To address this issue, the study aims to develop a sophisticated morphometric discrimination model that can accurately assess the sex of both Cipangopaludina chinensis and Ellamya purificata. This will enable us to manage their population sex ratios more effectively and enhance their reproductive success, ultimately contributing to the preservation and sustainable use of these valuable aquatic resources.

Methods This study delves into the morphological characteristics and reproductive potential of two distinct species within the Viviparidae family. Through meticulous measurements of various physical attributes such as body mass, shell dimensions including height and width, the study have constructed robust discriminant models for distinguishing between males and females of both species. These models are based on variance analysis and Fisher’s stepwise discriminant method. Furthermore, to elucidate the correlation between varying sex ratios and fecundity in these Viviparidae species, the study had designed an experimental setup comprising three breeding cohorts with controlled sex ratios of 1.0∶1.0, 1.5∶1.0, and 2.0∶1.0, respectively. This approach allows the auther to systematically investigate how changes in the proportion of males to females impact the reproductive output of each species.

Results In the discriminative model of C. chinensis male snail: F₁=−1.967X₁+2.965X₂+2.756X₃−75.999; female snail: F₂=−2.256X₁+2.096X₂+ 4.091X₃−78.587; in the discriminative model of E. purificata, male snail: F₁=1.216X₂+3.315X₄+2.899X₆−64.443; female snail: F₂=2.435X₂+4.247X₄−0.547X₆−58.138. After a meticulous verification process through backtracking, it had been determined that the overall accuracy rate for distinguishing between male and female individuals of E. purificata standed at an impressive 95.9%. Similarly, the comprehensive accuracy rate for identifying the gender of C. chinensis individuals reached a commendable 94.5%. The detailed investigation into the fecundity dynamics within the Viviparidae family revealed intriguing variations not only among different species but also with respect to varying male-to-female ratios. Specifically, the study observed a gradual decline in the number of reproductive Viviparidae within the population of C. chinensis, whereas this figure remained comparatively steady for E. purificata. Notably, the reproductive potential of E. purificata outperformed that of C. chinensis, boasting a fecundity level approximately five to seven times higher. Optimal reproductive success was achieved with a sex ratio ranging from 1.0∶1.0 to 1.5∶1.0; however, once the sex ratio escalated to 2.0∶1.0, there was a marked reduction in fecundity capabilities.

Conclusion In this experiment, the discriminant models of different male and female individuals were obtained by detection and analysis, and the accuracy rate was over 94.0%. Through the fecundity test, it was found that the optimal sex ratio was between 1.0∶1.0 and 1.5∶1.0.

Significance The results provide important reference for artificial breeding and breeding of the two kinds of Viviparidae, and have important guiding significance for promoting the scientific development of freshwater Viviparidae artificial breeding industry.