Abstract: Gobiids are widespread invasive species, with many species from this group usually invade into the same ecosystem simultaneously. Understanding the mechanisms underlying the coexi-stence of different gobiid species in the sympatric habitats is a key issue in fish invasion ecology. Incorporating morphological analyses, spatial distribution survey, and trophic analyses, we examined the coexistence strategy of Mugilogobius myxodermus and related species (the earlier invaders) in Dianchi Lake, Yunnan, China. Our results showed significant differences in morphology and spatial distribution among the four invasive gobies species (i.e., M. myxodermus, Micropercops swinhonis, Rhinogobius giurinus and Rhinogobius cliffordpopei). The spatial niche index of M. myxodermus was the highest. Food composition between M. myxodermus and other gobies was significantly different, with the former mainly feeding on Chydorus ovalis and Cypris sp. The trophic diversity index of M. myxodermus was the highest. Overall, we found that morphological differences, spatial niche diffe-rentiation, and trophic niche differentiation contributed to the coexistence of the gobies in Dianchi Lake, which could help M. myxodermus reduce interspecific competition. Importantly, the feeding strategy is the key factor determining population size and habitas of M. myxodermus during their competition with the other gobies, and finally contributing to the dominant position in the study area.

Key words: invasive gobies, sympatric coexistence, morphological differentiation, feeding differentiation, spatial distribution