July 29, 2025

What kind of island is Kuroshima?

As we have announced
on our website, "Kuroshima Laboratory Report" ( Kuroshima Laboratory Report - Kinkai Yusen Co., Ltd. ) All employees who participated were asked to submit a training report after the training.
There were many excellent submissions, and we would like to introduce one of them here.

　

Introduction What kind of island is Kuroshima?

Kuroshima is an island in the Yaeyama Islands of Okinawa Prefecture. The Yaeyama Islands are a collective name for the islands located about 400 km southwest of the main island of Okinawa, and are made up of 32 islands of various sizes, centered around Ishigaki Island. Kuroshima is one of the islands in the Yaeyama Islands, and is famous as "an island with more cows than people," and is also known as "Heart Island" because of its heart-shaped shape. The island is rich in nature, with black cows grazing freely everywhere. Tourists get around by rental motorbike or bicycle. It is a small and quiet island.

Kuroshima Research Institute

Founded in 1975, Kuroshima Research Institute is one of Okinawa's oldest marine biology research institutes. It is a small aquarium and museum, exhibiting a variety of creatures including fish, coconut crabs, vipers, sea turtles, peacocks, chickens, and sharks. It is also an interesting research institute with a wide range of exhibits, including specimens of Kuroshima's animals, coral, and debris from space. Although it is primarily a facility for researching sea turtles, it is open to the public and has become a tourist spot on Kuroshima.

Coastal cleanup

We spent an hour cleaning up Nishinohama Beach. The beach looks clean in the photos, but there was a lot of trash lying around, with a variety of trash washed up, including plastic bottles, glass bottles, cans, styrofoam, and floats. Some of the bottle labels were written in Chinese and Korean, and many of them appeared to have washed up from overseas. Although we worked in the heat, we were able to experience firsthand the importance of beach cleaning in creating an environment where sea turtles can lay their eggs on the beach. We have also cleaned beaches in Tomakomai, but there was far more trash at Nishinohama Beach. 10 people, including staff, worked together and collected enough trash to fill the back of a light truck and make three trips there.

Night walk to find sea turtles laying eggs

After dinner, we headed out to the west beach at 8pm to witness sea turtles laying their eggs.

Sea turtle release

On our last day on Kuroshima, we witnessed the release of green sea turtles for research purposes at the research institute. Sea turtles are endangered, so it is essential to constantly keep track of and observe the number of individuals and their whereabouts. The research institute also conducts tagging surveys. Sea turtles that come ashore to lay eggs or that are caught in fishing activities are tagged. This makes it possible to study the movements and growth of tagged sea turtles the next time they are found. To date, the Kuroshima research institute has used 5,000 tags.

　

Kuroshima Optional Training

Ranch experience

On Kuroshima, where the number of cows outnumbers the number of people, more than 3,000 cows are raised. We had the opportunity to experience feeding the cows and observe artificial insemination in the cowshed. Artificial insemination of cows is done entirely by hand. The uterus of a female cow in heat is touched, checked for engorgement, and sperm is injected. Sperm collected from a high-quality brand cow is said to fetch up to 10,000 yen. A cattle auction is held every two months, and dairy farmers from all over the country visit to raise the cows in their respective regions, which then become Yamagata Beef, Kobe Beef, and Matsusaka Beef. As many as 150 cows are auctioned at one time. All the cows live freely and are raised with love from their owners.

Boarding the oceanographic research vessel AKARI

I went on a snorkeling tour aboard the AKARI. The waters around Kuroshima are very clear, and although I've been to the ocean in Okinawa several times, it was the first time I'd seen such clear water. I was also able to observe the fish that live on Kuroshima, and I'll never forget the view of Kuroshima while cruising on the donated AKARI boat.

The fish on display at the Kuroshima Research Institute are often caught by people aboard the AKARI or by diving off the west coast, and we are pleased that they are useful for research and investigation.

Visit to the Tsushima-Maru Memorial Museum

On the final day of the training, we visited the Tsushima Maru Memorial Museum and had the opportunity to speak with Mr. Teruya (85 years old), who was on board the Tsushima Maru, was involved in an accident, was rescued, and now gives lectures as a storyteller.

The Tsushima Maru was a cargo ship operated by the parent company, Nippon Yusen, carrying evacuees from Naha to Nagasaki during the Pacific War. It sank 11 minutes after being hit by a torpedo from the U.S. Navy's Bowfin at 10:21 PM on August 22, 1944.
Teruya, who was rescued, was four years old at the time. He was on board the ship with his mother and older sister when it was attacked and jumped into the sea to escape. His mother then went looking for his sister, who had strayed, and Teruya grabbed onto a soy sauce lid and was rescued 16 hours later. That was the last time he saw his mother. Despite being a young child, Teruya vividly described his emotions and what he saw at the time.
During the war, a strict order was issued to keep the accident secret, and despite the deaths of over half the evacuees, the survivors were unable to even mourn their loss.
The Tsushima Maru Memorial Museum displays photographs of the situation at the time and of those who died, and listening to the voices of their families and those who were rescued, I was reminded that war should never happen.

Conclusion

By participating in the Kuroshima training, I was able to learn about the ecology of sea turtles, which I had only seen at the aquarium, and the creatures that live on the island, a side of Kuroshima that tourists would not get to see, and the charms of Kuroshima, a place loved by sea turtles and cows. The island's residents were warm and welcoming, and I am very grateful to the Kuroshima Research Institute for providing this opportunity.
The climate, clouds, and ocean views were completely different from those in Hokkaido, where I live. Everything was fresh and stimulating, and I have come to love Kuroshima. I strongly want to continue contributing to activities to protect sea turtles as part of environmental conservation. This training was an extremely valuable opportunity that significantly changed my perspective and values ​​on Okinawa and Kuroshima.

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