Underwater microphones detect dolphins in Sea of Japan bays about once every ten days

When residents of two coastal communities along the Sea of Japan reported observing dolphins in nearby waters, it caught the attention of some scientists. The marine environment has been changing rapidly in the Sea of Japan, which is partially enclosed by the Japanese archipelago and the Eurasian continent and connected to the ocean through shallow straits. Though dolphin sightings and bycatch records have been reported along the coast, basic ecological information on small odontocetes, such as dolphins and porpoises, has remained limited.