Round goby (Neogobius melanostomus) is a benthic freshwater fish native to the Ponto-Caspian region in Europe that was first recorded in the Laurentian Great Lakes basin in 1990 in the St. Clair River in Sarnia, Ontario. It has since become one of the major invasive species of the Great Lakes. The mechanisms through which round goby has become a successful invader are poorly understood. It has been hypothesized that phenotypic plasticity of species may influence their establishment, spread, and impact. If a species is phenotypically plastic, it could more easily adapt to a variety of environments. We examine whether phenotypic variation is present in round goby in the Laurentian Great Lakes and whether morphological variation in dorsal and lateral shape is related to habitat type and time since invasion. Morphological variation in preserved round goby specimens was analyzed for dorsal and lateral shape differences between lake, large river, and river habitats, waterbody of origin (Erie, Huron, Michigan, Ontario, Simcoe) and time since initial invasion (i.e., early, mid, recent) using a Procrustes ANOVA and visualized using a principal component analysis. There is significant variation in body shape among lake and river populations, which may be due to differences in water flows between these habitats. Lake specimens have an overall deeper body shape, whereas river specimens have an overall shallow body shape and large river specimens are intermediate in shape. The results of this study help better understand what morphological mechanisms facilitate invasions and provide valuable information for management decisions related to spread of round goby in the Great Lakes basin.

圆形虾虎鱼（Neogobius melanostomus) 是一种原产于欧洲蓬托-里海地区的底栖淡水鱼，于 1990 年在安大略省萨尼亚的圣克莱尔河的劳伦大湖盆地首次被记录。它已成为五大湖的主要入侵物种之一。人们对圆形虾虎鱼成为成功入侵者的机制知之甚少。据推测，物种的表型可塑性可能会影响它们的建立、传播和影响。如果一个物种在表型上是可塑性的，它就可以更容易地适应各种环境。我们检查了劳伦大湖的圆形虾虎鱼中是否存在表型变异，以及背侧和侧向形状的形态变异是否与栖息地类型和入侵时间有关。针对湖泊、大河和河流栖息地、起源水体（伊利、休伦、密歇根、安大略、西姆科）和自初次入侵以来的时间（即早期、中期，最近）使用 Procrustes 方差分析并使用主成分分析进行可视化。湖泊和河流种群之间的体型存在显着差异，这可能是由于这些栖息地之间的水流量不同。湖泊标本整体体形较深，而河流标本整体体形较浅，大河流标本体形中等。