Sado Wildlife in Focus | Swimming with Damselfish and Underwater Wonders

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Surrounded by the sea, Sado Island is a paradise for divers who can explore its waters all year round. Because it faces the Sea of Japan, you won't find the vividly colored tropical fish of warmer seas. But instead, you can get up close to the familiar species that often appear on Japanese dinner tables.

Normally, I spend my days photographing the crested ibis, a Special Natural Monument of Japan, but this time, I turned my camera toward the creatures beneath the waves.

It was mid-October when I visited Ogi Coast, on the island's southwest side. The air was starting to feel cool, but the sea was still a surprisingly warm 22°C. 

Guided by diving instructor Hiroyuki Koide from the diving service Freeway, I headed to a spot known for its schools of black damselfish. It didn't take long before we encountered a massive swarm.

Thousands of damselfish moved together as if forming a path through the water, swaying gently with the current. Even when divers approached, they didn't scatter. I couldn't help but want to follow their shimmering path deeper into the sea.

Divers' Favorite Spot

Damselfish grow to about ten centimeters (around 4 inches) long and live along Japan's coasts from Aomori to Kyushu, spending the winter in the Sea of Japan. They belong to the same family as the brilliantly blue damselfish found on tropical coral reefs, but those around Sado are darker and less colorful, with larger scales and a small, reflective spot behind their dorsal fin.

This dive spot is rich in life because the current hits the rocks, bringing with it a steady supply of plankton and other food. The damselfish, knowing divers pose no threat, show little fear of humans.

Because their meat has a strong odor, anglers often release them instead of eating them. In some regions, however, they're considered a delicacy. On Sado, humans are not among their predators.

Octopus Eggs and Rock Oysters

Among the rocky reefs, I also spotted what looked like clusters of sea anemones — but they were actually octopus eggs. Nearby, I found oysters clinging to the rocks.

A female octopus lays eggs only once in her lifetime, but I didn't manage to find the mother this time. Harvesting rock oysters here is prohibited, so I couldn't taste them — but I learned that wild-caught ones served at local restaurants are considered a delicacy.

Koide, who has been an instructor for 14 years, told me, "These small schools of fish will soon grow larger. Then yellowtail and amberjack will come to hunt them, and we'll start seeing some truly powerful scenes of predation."

While damselfish have nothing to fear from humans, the ocean is full of predators.

This dive site is also known for a submerged jizo stone statue. Including its pedestal, it stands about two meters tall and was placed there roughly 40 years ago to pray for safety at sea. Despite decades underwater, it remains in remarkably good condition, as if watching over divers and keeping them safe.

The rich, living waters around Sado Island are full of wonders waiting to be discovered.

Special thanks to: Diving Service Freeway.

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• Sado Wildlife in Focus | Autumn, When the Crested Ibis is Most Beautiful
• Sado Wildlife in Focus | Swallows, Our Lucky Feathered Neighbors

This is the 27th in the series Sado Wildlife in Focus by photojournalist Fumie Oyama.

Fumie Oyama is a two-time winner of the Japan Newspaper Publishers & Editors Association Award as a photographer for The Sankei Shimbun. After covering the reintroduction of the crested ibis to the wild for 11 years, Oyama left the company in 2020 to move to Sado Island. There, he continues to photograph the ibis and other wildlife while engaging in farming. He currently promotes the charms of Sado Island as a photojournalist. Follow Fumie Oyama on Instagram.

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