INFLUENCE OF EXTENSIVE HII RIVER MODIFICATION ON THE SPAWNING HABITAT OF ICE GOBY

Abstract

In Hii River modification (2010-2015), the nature oriented methods such as the slide down dredging which does not change the cross profile and gradient of the river, removal and decentralization of the weirs and returning coarse sediment components to the riverbed after the dredging were adapted. Though some reports showed the positive effects to fish habitats such as more fishes migrated to the upstream of the modified area，the effects of this modification was not assessed enough especially in the downstream and estuarine area. In this study, we focused on the Ice goby (Leucopsarion petersii) which specifically uses the cobble environment of the upper estuarine area as its spawning habitat．The influence of the river modification to the spawning habitat were investigated.