Compliments of Professor Masashi Yamaguchi
The time when the pictures were taken was quite interesting, as a mass-mortality of T. gigas had taken place (detailed account was reported by Rick Braley) and we found a lot of large dead clams scattered in the lagoon at Lizard Island.
The boys in the pictures are: Masaru (age 11 at that time) with a pair of goggles and Takashi Yamaguchi (13 years old) with his face mask. They are both big boys now.
I have my own web pages on various aspects on giant clams, though texts only in Japanese, with many photographs in my home page.