MIKURAJIMA, Tokyo--Dolphin-watching season has opened in waters off this island, home to at least 150 often-curious Indo-Pacific bottlenose dolphins.

Tour participants can observe the species underwater in calm waters around Mikurajima island, 200 kilometers south of Tokyo in the Izu island chain.

On a recent tour, dolphins showed interest in humans, looking into their cameras and swimming nearby. Calves born just this year were among a pod of dolphins observed.

Tour participants are supposed to abide by rules set to maintain good relations with the cetaceans, including not touching the marine mammals and not disturbing their movement.

According to the Mikurajima village’s tourist information center, about 150 Indo-Pacific bottlenose dolphins were confirmed to exist around the island last year. An average of 10 calves are born annually.

The dolphins attract people not only from Japan, but also from Taiwan and elsewhere overseas, according to the information center.

The season lasts through October.

Visitors to the island are advised to book lodgings in advance because the number of available rooms is limited.