Feeding ecology and trophic adaptability of the mudskipper Scartelaos histophorus in south-western Vietnam

Context Feeding ecology provides insights into trophic strategies and ecological adaptability in estuarine fishes. Aims This study examined the feeding ecology of Scartelaos histophorus in relation to sex, season, region and month. Methods In total, 1436 individuals were collected across seasons and regions. Relative gut length (RGL) and stomach content analyses were used to evaluate feeding habits and dietary variation. Key results Mean RGL was 0.98 ± 0.01 s.e. and differed significantly among sex, season, region and month. Females showed higher RGL values than did males, whereas elevated values occurred during the wet season and in the northern Hau River region. Dietary analysis showed that 46.8% of individuals contained food, with Acetes spp. dominating the diet (80.09% of total biovolume). Secondary prey included insects, small fish and Uca sp. PERMANOVA detected no significant differences in diet composition among sex, season or region. Conclusions Scartelaos histophorus is a generalist carnivore occupying an intermediate trophic niche. Despite spatiotemporal variation in feeding patterns, the species exhibits notable ecological plasticity in response to prey availability and environmental conditions. Implications These findings provide a basis for future studies of trophic ecology and adaptation in estuarine ecosystems.