We are conducting a diving survey on Oshima
Kojima Island, an uninhabited island near the entrance to the Tsushima Warm
Current in the Tsugaru Strait, which separates Hokkaido and Aomori Prefectures.
Toward the end of the survey, a large school of bluefin tuna suddenly appeared.
It is rare to see schools of tuna in the wild, so this is a valuable image. In
addition to this, sharks sometimes “accompany” the group.
Nudibranchs, corals, and other benthic
animals also appear in this video. In addition, sea squirts are collected in
underwater caves. This sea squirt has been found to contain a component related
to the prevention of Alzheimer’s disease.