Habitat-associated morphological divergence of the three-spined stickleback, Gasterosteus aculeatus populations was investigated in the southern Caspian Sea basin using landmark-based geometric morphometric method to understand the population structure of this invasive species. A total of 127 specimens were collected from three stations, including the Babol River estuary (center), Gomishan Wetland (east) and the Gisum Coast (west). The left side of each specimen was photographed and 23 landmarks-points were selected to extract body shape data. After generalized procrustes, the data analysis was analyzed using principal components analysis, multivariate analysis of variance/canonical variate analysis and cluster analysis. The results showed a significant difference in body shape between three studied populations (P < 0.001), that were related to the depth and length of the head, the body and caudal peduncle and the positions of the pectoral and ventral fins. Morphological differences of the studied populations can be considered as response to environmental characteristics of their habitats, showing G. aculeatus as a highly successful exotic species to expand its distribution area in the Caspian Sea.

三棘式棘背鱼Gasterosteus aculeatus的与生境相关的形态差异使用基于地标的几何形态计量学方法对里海南部盆地的种群进行了调查，以了解这种入侵物种的种群结构。从巴博尔河河口（中部），戈米山湿地（东部）和吉苏姆海岸（西部）三个站共采集了127个标本。拍摄每个标本的左侧，并选择23个界标点以提取身体形状数据。经过广义过程后，使用主成分分析，方差/标准变量分析和聚类分析进行数据分析。结果显示，三个研究人群的体形差异显着（P <0.001），这与头部，身体和尾柄的深度和长度以及胸鳍和腹鳍的位置有关。被研究种群的形态学差异可被视为对栖息地环境特征的反应，这表明刺G（G。aculeatus）是一种非常成功的外来物种，可以扩大其在里海的分布范围。