Survey site (IMAGE) Hokkaido University Caption The tributary of the Ito River in Hakodate, Hokkaido, where the field survey was carried out (Photo: Ryota Hasegawa). Credit Ryota Hasegawa Usage Restrictions This image is copyrighted but may be used to report on this press rleease if credited as instructed. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.