A total of 61, 388 fish specimens, representing about 60 species, were collected by monthly seine-net (mesh size 0.8 mm) samplings at the seven tidelands in the inner Tokyo Bay, Pacific coast of central Japan, from April 1997 to March 1998. Two gobiid species, Acanthogobius flavimanus and Chaenogobius macrognathos, were the most abundant species, contributing 52.6 and 20.7% of the total number of fishes, followed by Chaenogobius castaneus (7.7%), Lateolabrax japonicus (6.3%) and Mugil cephalus cephalus (6.0%). Eight “estuarine” and 19 “marine” species, which occupying 99.4% of total number of fishes, were highly possibly c0onsidered to depend on tidelands for their considerable part of life history, because of the occurrence of some developmental stages. The diversity of fish community was higher in Obitsu River and Edo River than in other five sites, in the first two rivers, large tidelands having remained in spite of coastal construction since 1950's. The results of this study would indicate that the diversity of fish community at tidelands reflect more or less an impact of emvironmental changes by the reclamation of the inner Tokyo Bay.
