ダム堆砂の干潟生物に対する基盤材料としての評価　─アサリ、チゴガニ、コアマモを対象として─

抄録

To elucidate possibility of using sedimentary soil at reservoirs as a tidal flat substratum material of a river mouth or coastal region, habitat assessment was conducted on short necked clam (Ruditapes philippinarum), fiddler crab (Ilyoplax pusillus) and slender eelgrass (Zostera japonica) which are the representative organisms in tidal flats. Experiments of the habitat assessment were performed indoor using 30-100L tanks in which water temperature, tide level and cycle, light intensity as well as wave were controlled. Burrow ability, survival rate and condition factor of the short necked clams which were reared at the sedimentary soil substratum for 90 days showed no distinct difference from these parameters of those at natural tidal flat substratum. With respect to the fiddler crab, its activity patterns such as sand dumpling and burrow hole creating were no different between the sedimentary soil substratum and the natural tidal flat substratum. Moreover, the survival rate and fresh weight increase rate for 90 days rearing were almost similar between both substrata. Survival rate and growth conditions of the slender eelgrass which was transplanted to the sedimentary soil substratum showed better result compared with the natural tidal flat substratum. By these experiment results, we suggested that the sedimentary soil at reservoirs could be an adequate substratum material for habitat of the organisms.