Research employing a biologging system on the Japanese lates fish in the Shimanto River has revealed some previously unknown behaviors. In order to continue to make use of the rich natural environment of the Shimanto river, the lates' habitat, appropriate mountain and forest management must be carried out not only by Kochi prefecture but in concert with the upstream Ehime prefecture. It is also essential to carry out monitoring of changes in seawater inflow due to riverbed shifts and the rise and fall of sandbars.