Yoshio Misaki, chief fisherman of the Japanese trawler irradiated by a U.S. hydrogen bomb test in the Marshall Islands in 1954, died Thursday of pneumonia at a hospital in his hometown of Yaizu, Shizuoka Prefecture, his family said Friday. He was 90.

Misaki was one of the 23 crew members of the tuna fishing boat Fukuryu Maru No. 5, also known as the Lucky Dragon. The boat was sailing near the western Pacific archipelago when the United States set off a hydrogen bomb at Bikini Atoll on March 1, 1954.

Contaminated by debris from the test, the crew came down with acute radiation sickness that claimed chief radio operator Aikichi Kuboyama six months afterward at the age 40.

Misaki became an ardent supporter of nuclear disarmament and often gave talks about his experiences.

In 2011, he made his first visit to an exhibition hall in Tokyo where the Lucky Dragon is on display.