Hello everyone, I'm underwater photographer Shota Ishino. In the last episode, we explored the Shiretoko Peninsula at the far northeastern tip of Japan. Shiretoko sits at the southern end of the Sea of Okhotsk — the southernmost point that drift ice can reach. Drift ice is a spectacular phenomenon born from the enclosed nature of the Sea of Okhotsk, yet with climate change, there may come a day when it can no longer be seen. Shiretoko is one of the regions that embodies the rich diversity of Japan's natural environment.
In this episode, we turn our attention to one of the key ocean currents that makes Japan's abundant natural resources possible: the Kuroshio Current.
Yonaguni: The Japanese Island Closest to Taiwan
What I'd like to share with you this time is Yonaguni — Japan's westernmost island, just 111 km from Taiwan. On a clear day with good visibility, Taiwan is actually visible from Yonaguni. I find myself wondering: can our Taiwanese friends see Yonaguni from their side too?
The First Island in Japan to Greet the Kuroshio
Yonaguni is the very first point in Japan where the Kuroshio Current arrives. Originating from the Coral Triangle — the most biodiverse marine region on Earth — the Kuroshio passes through Taiwan and delivers an extraordinary wealth of marine life to Japan. My reason for visiting Yonaguni this time was to photograph the Hammerhead Shark aggregation.
From December through March each year, large schools of Hammerhead Sharks can be observed around Yonaguni. Places in the world where you have a high chance of encountering a school of Hammerhead Sharks underwater are extremely rare, which is exactly what makes Yonaguni a dream destination for divers. I visited at the end of March — near the tail end of the season — when luck can run thin, and on some days you might not spot a single one.
How to Dive at Yonaguni
Searching for Hammerhead Sharks at Yonaguni means drift diving. Diving here safely requires considerable dive experience; the currents are strong, and solid swimming ability is essential.
Your dive guide or assistant divemaster will carry a surface marker buoy (SMB) and dive alongside you, so always be careful not to get separated from your buddy.
Since you're diving in a natural habitat, there's no guarantee of seeing any particular species. However, an experienced dive guide who can read the currents will still give you a strong chance of encountering the Hammerhead Sharks.
The Allure of Hammerhead Sharks
The most captivating feature of the Hammerhead Shark is its distinctive silhouette. Its hammer-shaped head — the origin of the English name "Hammerhead Shark" — is precisely what fuels my desire to photograph them. Their gentle temperament is another draw, of course; if they were aggressive, I certainly wouldn't want to get anywhere near them.
At Yonaguni, it's sometimes possible to witness hundreds of Hammerhead Sharks swimming together in a formation that flows through the sea like a river — a sight known as the "Hammer River."
What Makes Yonaguni So Captivating
Yonaguni's appeal extends well beyond the Hammerhead Sharks. The rich layers of marine life delivered by the Kuroshio are a major highlight in their own right. During winter, most visiting divers come specifically for the Hammerhead Sharks, making it difficult to fit other dive sites into the schedule. Outside the Hammerhead season, however, Yonaguni offers a range of rare fish species well worth seeking out.
Schools of barracuda and large pelagics such as dogtooth tuna can be seen here, and with a little luck you might even cross paths with a sailfish or a Whale Shark.
Then there are the famous underwater ruins off Yonaguni — a remarkable natural wonder in their own right. There is truly something to discover at Yonaguni all year round.
The Gift of the Kuroshio
The thriving marine ecosystem around Yonaguni owes everything to the Kuroshio Current. Another great beneficiary of the current is the abundance of plankton it carries.
Plankton was one of the reasons I made the journey to Yonaguni. The season when Hammerhead Sharks can be observed happens to coincide with a period of prolific plankton blooms. As a result, just before wrapping up a Hammerhead dive, it's common to encounter a wonderful array of beautiful plankton during the safety stop.
There are many extraordinary planktonic species here that simply cannot be found elsewhere in Japan — creatures so small that even experienced divers find them difficult to spot. As a photographer, I strive to capture the beauty of these tiny organisms that underpin the entire marine ecosystem, and I firmly believe Yonaguni is one of the finest places in the world for plankton photography.
With that in mind, I have organised dive trips to Yonaguni with a specific focus on plankton. Below are some of the photographs I have taken of plankton here:
Bramidae Juvenile: Encountering a fish that hasn't yet been well documented is one of the most thrilling things that can happen on a dive.
My first-ever encounter with an extremely rare juvenile frogfish.
Juveniles of deep-sea squid are frequently encountered here, such as Leachia pacifica.
Juveniles of deep-sea fish are also commonly seen — among them, the oarfish.
Please join me in sharing the joy of discovering these tiny, mysterious creatures!
Further Reading
