Mudskippers are the most abundant vertebrate on both tropical and subtropical tidal mudflat that significant influence the stable of the food web in estuary ecosystem. To live on the border of land and sea, they are sensitive to human activity and the environment change. Hence, mudskippers can be considered as bioindicators of wetlands.

Research of mudskippers in Taiwan focused on physiology and morphology. Studies of ecology and habitat preference are rare, and most of the experiments were done in the laboratory. The factors that influence the distribution of mudskippers in the field are still unclear. This study focuses on how environmental factors, including temperature, salinity, tidal level and sediment in Tamsui estuary, affect the distribution of mudskippers in the field.

Three species of mudskippers were recorded in our study site. Boleophthalmus pectinirostris and Scartelaos histophorus were active near the riverbank. In contrast, Periophthalmus modestus was found closer to land.

Nowadays, wetlands are destructed and disappeared abruptly. How to monitor and evaluate the wetland ecosystem is now in urgent. This study provides a preliminary research for mudskipper as a bioindicator of wetland environmental change.