ABOUT A CHANGE OF THE CREATURE COMPOSITION AFTER THE HARBOR CONSTRUCTION IN THE SANDY BEACH COAST : EXAMPLE OF SHICHIRI-NAGAHAMA PORT

Abstract

 In "Shichiri-Nagahama Port", the erosion of the sandy beach is remarkable in the area along the shore of the northeast side. Block of the drift sand by the harbor construction is considered as one of the factors. Therefore I divided it into 3 domains of A - C for approximately 3km of the area along the shore of the northeast side of "Shichiri-Nagahama Port" where the erosion of the sandy beach was remarkable and investigated it. As a result of survey of bathymetry from 2011 through 2014 and creature investigation of 2014, remarkable sedimentation (4.23m) was confirmed in the A domain nearest the harbor, and it was thought that a stable sandy area was formed because Nitidotellina hokkaidoensis or Paralichthyidae were confirmed a lot. It was thought that in late years the erosion of the sandy beach was stopping because with a little amount of change from 2011 in the B domain of the sea cliff, and a beachline was stabilized. On the other hand, in the C domain that was far from the harbor most, as for the remarkable erosion, it was thought that it was unstable environment although I was not seen because there was little number of the confirmation of the creature.