How many people rode the same boat as you on the way here? How many of those people got off at Chiburijima?
At present, the population of Chiburijima is about 600 people. During the Taishō Period (1912-1926), however, the population was as high as 2500 people. This fell to 1700 people with and increasing need to leave the island for work, and rose again during World War II (WWII) to 2300 people as Chiburijima served as a place for evacuees.
After the war ended, the need to leave the island for work was nevertheless prevalent, and there were fewer people who returned home to the island. This is why the population now stands at about 600 people, though Obon is still one holiday that will bring many people home and liven up the island.
During Obon, boats have no place to sit, and typical households grow 3 to 4 times larger, causing a huge ruckus when it is time to send people off. While the five-colored tape of the ships dance wildly in the wind, people crowd the port, waving to their departing family members until the steam whistle is no longer heard and the boat is no longer seen.
And thus Chiburijima returns to silence.