High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Daigo Fukury Maru was a Japanese tuna fishing boat, which was exposed to and contaminated by nuclear fallout from the United States' Castle Bravo thermonuclear device test on Bikini Atoll, on March 1, 1954. Kuboyama Aikichi, the boat's chief radioman, died less than seven months later, on September 23, 1954, suffering from acute radiation syndrome. He is considered the first victim of the hydrogen bomb of Operation Castle Bravo.