While the city of Shima in Mie Prefecture has long been known for its tradition of ama female free divers, men have similarly been hunting the depths for abalone and other sea creatures without the assistance of breathing devices.

Among them is Yushi Ikeda, 30, who lives in the Azena district of Shima.

Ikeda said he began working as a free diver around the age of 18 because his mother was an ama.

Every day Ikeda dives in the sea with his 20-year-old wife, Mana, who just began her apprenticeship as an ama in April.

"It's a lot of fun. I also love the ocean, so this is my calling," he said.

According to the Toba Sea-Folk Museum in the adjacent city of Toba, there were some 320 male free divers in Mie Prefecture in 2014.

This compares with some 760 of their female counterparts.

Takuya Agata, a curator at the museum, said although male free divers also existed in the old days, only female divers were depicted in ukiyo-e prints during the Edo Period between the 17th and 19th centuries.

"The trend was the same in photography," he said.

"Artists of all ages and cultures have likely been inclined to prefer women, because they are prettier, as the subject of their works."