Estimation of Japanese sandeel (Ammodytes personatus) distribution in the northern coast of Hokkaido, Japan, using a quantitative echo sounder - Safruddin, Kazuhiko Itaya, Keiji Maeda, Koki Abe, Ryuichi Matsukura, Hiroki Yasuma and Kazushi Miyashita (Asian Fisheries Acoustics Society, 2014)