Article : 波左間海中公園

Hasama marine park

The diving point like an amusement park. It is located south end of Boso peninsula. Chiba Tateyama. The article linked is in Japanese.
I introduced that place detailed also in Guide Book “New 50 Best Dives in Japan” (in English). On sale at Amazon.com

Wide Angle : Purple sea pen ヤナギウミエラ

Virgularia gustaviana (Herklots, 1863)

Sea pen forest at Hasama

umi-era in Japanese

These rare sea lives that appear to be bird feathers stuck in the bottom of the sand is called a Sea pen. In Japanese, Umi-Era. The Umi means the sea. Era means gills. Sea pens belong to octocoralia, so-called soft coral, like a Sea Wip or tree coral. Ordinarily, this species is, during the day, it hides into the sand, and when it gets dark, it is appearing from the sand, and spreads its wings. However, in Hasama, even in the daytime, we can often see the mysterious sight of the numbers of Sea pens are standing like the forest. Hasama, Tateyama, Chiba, Japan. -18m.