Yakushima: Japan’s First Natural World Heritage Site

Descending through the clear blue water towards a huge rocky boulder, my guide leads me towards a photogenic pygmy seahorse. Clinging to a branch of coral and swaying to and fro in the gentle current, it’s a shy and elusive creature that turns its back to me before deciding otherwise. Doubt and disbelief turn to excitement as it turns to face me and I keep watching, determined to make the most of the little time I have there. Nearby is an area of whip coral playing host to a few gobies and gorgonian pandalid shrimp while further up in the shallows shoaling fish, from marauding sea goldies to patrolling square-spot fairy basslets, are resident in huge numbers.

BIODIVERSITY, LAND AND SEA
The gateway to this scene is Yakushima, a humid subtropical island in the East China Sea in southern Japan’s Kagoshima Prefecture. But despite its prolific marine life, Yakushima is not exactly known as a diving destination. More commonly, visitors go to soak up the atmosphere of the ancient forest, see the giant Yaku cedar “Jomon-sugi” (said to be 7,200 years old) or experience the many hiking trails. Add to this is a huge amount of rain; at 40,000–10,000mm a year, Yakushima may have extremely high precipitation, but this creates a warm and rich natural environment that’s a stunning shade of green with pristine forests and vegetation. It’s precisely these features that led to the island becoming one of Japan’s first natural World Heritage Sites back in 1993.

CRITTER-CARRYING CURRENTS
But underneath this warm, temperate ecosystem lies another world that’s just as rich and varied. The seas off Yakushima are blessed with the warm Kuroshio Current that travels from east of the Philippines to the Pacific coast of southern Japan, heading past Yakushima and north towards the Pacific. As it passes Yakushima, it funnels water rich with nutrients, plankton and schools of reef fish from further south, promoting healthy growth and unique and varied marine life. The flow rate and direction change according to the season, winds and water temperature; this is another reason for the island’s rich underwater diversity. Yakushima is also at the biogeographic boundary between the tropical and temperate regions, and all the climatic zones of the Japanese islands are concentrated there. Despite this, the diving here is yet to be fully discovered, but for those who do encounter it, a treasure trove of life awaits.

Cuttlefish laying their eggs in Yukushima’s clear waters (Photo by Shigeru Haruzaki)

SITES AND HIGHLIGHTS
Yakushima’s main dive sites lie along the north coast. The area is a world of sandy carpets, rocky gardens, boulders and reefs that are jam-packed and vibrant with reef fish species such as damsels, butterflies, angels and more. Described as Japan’s premier nesting site for turtles, it’s also no surprise to occasionally encounter one or two disappearing into the blue when diving here. Gliding lazily by or 1. sniffing around in the organic detritus, the turtles are so relaxed around divers that they are more than happy to nestle into the rocks close by or put on a show of graceful floating. The north coast is also home to signature species like jawfish, brightly-coloured nudibranchs flourishing over the rocks, and yellow-spotted scorpionfish, while other treats lie in store: the ubiquitous lionfish, and Moorish idols hiding in the alcoves.

One of Yakushima’s most popular dive sites is “Zero-sen” in an area called Isso along the north coast, no more than five minutes by boat from the mainland. It’s the final resting place of a Mitsubishi A6M zero, a long-range fighter aircraft operated by the Japanese Imperial Navy from 1940–1945. Dropping into the water, the scene seems a little monotonous with a carpet of white sand that spreads out for miles. But then a dark cluster emerges, and, descending to about 20 metres, it soon becomes clear that this is the front part of the aircraft, a safe haven for the many small fish species that dart out of harm’s way as divers approach. There are also huge numbers of sponges, from barrel sponges to the encrusting varieties, and a couple of territorial moray eels that curiously poke their heads out from within the wreckage. Communities of slender sweepers and black spot cardinalfish share their home with white socks shrimps and some ever-present cleaner shrimps.

NAVIGATOR

Getting there:

From Tokyo’s Haneda airport, fly with Japan Airlines to Kagoshima city and change for another flight to Yakushima. The journey from Tokyo to Yakushima is just over three hours. High speed jetfoil boats also operate daily between Kagoshima and Yakushima, departing every one to three hours.

Best time to dive:

Between July and November. Water temperatures range from 26°C to 29°C in July to 23°C to 25°C in November. Visibility can be around 20 to 30 metres.

Don’t dive without:

A camera. There is a staggering range of marine life to photograph!

Essential training:

Open Water is okay, but Advanced is recommended. Most dives can reach 20 metres or more.

Arriving:

Most visitors are permitted to stay in Japan for up to 90 days for tourism. Check with your local embassy.

For more information:

www.yesyakushima.com
www.yakumonkey.com

Dive with:

Yakushima Diving Service Mori to Umi

Currency:

Yen (JPY)
USD

Time zone:

UCT/GMT +9

Languages:

Japanese (some English is spoken on the island too)

Read the rest of this article in Issue 3/2015, AA No.82 of Scuba Diver magazine by subscribing here or check out all of our publications here.