Morphological Difference Analysis of Triplophysa strauchii from Different Geographical Populations in Xinjiang, China

Spotted stone loach (Triplophysa strauchii), a common fish species in Xinjiang, China, is ecologically pivotal within the local ecosystem; regrettably, human-induced factors like habitat destruction, pollution, and overfishing have gravely imperiled its survival, and compounding this is the dearth of research on the morphological disparities among its geographically diverse populations. Thus, between April and October 2024, 198 specimens were procured from Sayram Lake, Khamusigou Reservoir, and Chaiwopu Lake using cage traps and gillnets; post-collection, an array of morphological metrics were meticulously measured, and then statistical methods such as one-way analysis of variance (ANOVA), principal component analysis (PCA), stepwise discriminant analysis, and cluster analysis were employed for comprehensive data interrogation. Findings show that, across all sampled populations, the mean values of the total length (X1), body length (X2), body height (X3), and body width (X4) of the Chaiwopu Lake population are significantly lower than those of the Sayram Lake population and the Khamusigou Reservoir population; except for head length, the Khamusigou Reservoir population has lower variability in other morphological traits compared to the others. Moreover, significant divergences were detected in multiple trait ratios among the populations; PCA yielded five principal components, cumulatively accounting for 77.45% of the total variance, spotlighting the key ratios; discriminant analysis further validated highly significant morphological distinctions (p < 0.01), with the Khamusigou Reservoir population having the highest discriminant accuracy; cluster analysis graphically showed the Sayram Lake and Chaiwopu Lake populations clustering together while the Khamusigou Reservoir population formed a separate cluster; and the Chaiwopu Lake population had the most pronounced divergence in morphological traits. This research not only provides novel perspectives on the adaptive evolutionary mechanisms of T. strauchii but also serves as a cornerstone for formulating evidence-based conservation and management strategies for this species.