In April 2025, 7-Eleven stores across Aomori and Miyagi prefectures offered a limited-edition Uni Miso Onigiri made with premium steamed sea urchin from Kita-Sanriku Factory Ltd..

Kita-Sanriku Factory is tackling the issue of “Isoyake”—the degradation of coastal marine ecosystems—through its regenerative aquaculture technology for sea urchins. Its sustainably farmed sea urchin was selected as the key ingredient for the miso blend used in the new onigiri developed in partnership with Seven-Eleven Japan Co. The product was available at approximately 100 Seven-Eleven stores in Aomori and Miyagi prefectures (as of February 2025) for a limited time from 1st April 2025. By increasing the consumption of sea urchin which is one of the causes of “Iso-yake”, we can help restore seaweed-rich coastal ecosystems.

“Sea Urchin Miso Onigiri,” A Taste of Sanriku that burts with flavor 

This product uses Northern Sea Urchin carefully cultivated by fishermen in the town of Hirono, Iwate prefecture. Juvenile urchins are released into the sea and later transferred to a coastal Sea Urchin Ranch®, where they are fed a rich diet of kelp. Once matured, the sea urchins are steamed to concentrate their umami flavor. The resulting “steamed sea urchin” is then combined with Sendai miso, a rice miso that has been aged for a long time, to create the perfect combination of salty, sweet, and savory flavors.  Wrapped in rice from the Tohoku region, this onigiri offers a delicious way to “taste Tohoku” and enjoy the essence of the Sanriku seashore in every bite.

Product name: “Uni (sea urchin) miso rice ball using steamed sea urchin from Hirono Town” 

Price: 320 yen (345.6 yen including tax)

Eating is the Answer to “Iso-yake”s. Initiatives to Enrich the World’s Oceans 

In recent years, “Iso-yake,” or the drying up of coastal seaweed beds where marine plants once thrived, has become a serious problem. One of the causes is overgrazing by marine organisms such as sea urchins, which consume all the seaweed.In areas where these seaweed beds have already disappeared, the remaining “skinny sea urchins” on the seafloor are considered unmarketable and often discarded due to their poor quality and lack of commercial value. Along with the depletion of seaweed beds, the catch of sea urchin as a commodity is also declining, creating a vicious cycle.

Kita-Sanriku Factory has succeeded in improving the quality of sea urchin, which has lost its economic value due to rocky shore depletion, using proprietary technology established in collaboration with Hokkaido University, etc. In June 2025, a large-scale land-based aquaculture facility will be constructed to establish a highly efficient production system. Our goal is to enrich the world’s oceans byt ackling climate change with cutting-edge Japanese technology while providing a delicious experience unparalleled anywhere in the world.

We believe that creating a sustainable cycle of “eating sea urchin” → “decreasing the number of sea urchins in the sea” → “increasing seaweed” → “ensuring biodiversity in the sea” is essential to bringing life back to our oceans. We will accelerate this cycle, and at the same time, we will provide a tasty solution to the global issue of “Iso-yake”.

About Seven-Eleven Japan Co. 

Seven-Eleven Japan is the franchise chain headquarters for the Seven-Eleven convenience store chain, which operates more than 21,000 stores nationwide. The company offers a wide range of products and services, including mid-sized meals such as rice balls, boxed lunches, and prepared foods, as well as daily necessities and government services. With a focus on being a “close and convenient” presence in customers’ daily lives, Seven-Eleven Japan continues to evolve as a reliable and accessible neighborhood store.

About Kita-Sanriku Factory

Kita-Sanriku Factory is a leading company developing high-quality sea urchin brands in the town of Hirono, Iwate Prefecture, home to the world’s only “Sea Urchin Farm ®︎”. With the mission of “Enriching the world’s oceans from Kita Sanriku,” the company is leveraging its expertise in raising high-quality sea urchins to connect with the world through its new “sea urchin regenerative aquaculture system” technology and promote initiatives to create a sustainable future for the marine industry. We established an Australian corporation in 2023 and are expanding our business both domestically and internationally.

Yanmar Holdings Co., Ltd., and Kita-Sanriku Factory Co., Ltd. launched a full-scale pilot project on April 1, 2025, to develop a land-based sea urchin aquaculture system aimed at addressing “Isoyake”, or coastal ocean desertification.

The project is part of the Japan’s Small Business Innovation and Research (SBIR) program, which was selected by the Ministry of Agriculture, Forestry and Fisheries in October 2024. The project, with a total budget of 920 million yen, will focus on scalable, short-term aquaculture technology for deployment both in Japan and overseas.

The two companies will construct a large-scale land-based aquaculture facility in Hirono, Iwate Prefecture, with completion scheduled for autumn 2025. The facility will showcase UNI-VERSE systems®, an aquaculture solution designed to accelerate sea urchin growth and improve quality. The goal is to demonstrate efficient breeding systems capable of producing high-quality sea urchins for both local markets and export.

Tackling Isoyake with Regenerative Aquaculture

Isoyake, or coastal ocean desertification, a growing environmental issue characterized by the loss of seaweed beds along Japan’s coastal areas. In response to the threat of ocean desertification, which is partially attributed to overgrazing of seaweed by marine organisms such as sea urchins, Kita-Sanriku Factory has started an initiative called “Sea Urchin Regeneration and Cultivation”. This project aims to transform undernourished sea urchins – previously discarded as having no commercial value – into premium seafood products. By feeding the sea urchins for a short period of time, the company was able to greatly improve the size, color, and quality, and succeeded in realizing a taste comparable to that of the natural product. This advancement also enables year-round shipping, including the winter months when sea urchin are typically not available. It is also expected that the land-based aquaculture system will allow seaweed beds to recover, alleviating the problem of Isoyake.

This system was developed over more than seven years in collaboration with Associate Professor Ura and his team at Hokkaido University. The sea urchin feed “Hagukumutane®” and the structure of the fish tank and water tank are patented technologies of the Kita-Sanriku Factory.

■ Yanmar Holdings’ Aquaculture-Related Technologies for Sustainable Fisheries

The Yanmar Group brings extensive expertise in land-based aquaculture systems, including fish tanks, automated tank washers, and shellfish seed technologies. The company’s advanced fluid analysis and automatic cleaning technologies will help optimize environmental controls in the new aquaculture system. Together with Kita-Sanriku Factory, Yanmar aims to refine the UNI-VERSE systems® technology to enable the efficient and sustainable production of high-quality sea urchins for export.

■Global Reach and Export Plans

While international demand for Japanese sea urchins is increasing, securing a high-quality supply has become more difficult due to a rise in the number of “skinny” sea urchins with extremely small gonads, the edible part of sea urchins. The regenerative aquaculture model developed by Kita-Sanriku Factory, in collaboration with the Graduate School of Fisheries Science of Hokkaido University and other research institutions, aims to address this supply gap and promote sustainable practices worldwide.

Kita-Sanriku Factory plans to export UNI-VERSE systems® sea urchins to the EU, the U.S., Dubai, Thailand, and other countries around the world. In 2025, the company will exhibit at four major seafood fairs in the world in Barcelona, Boston, Dubai, and Bangkok, establishing a global commercial distribution network.

About Yanmar

Founded in Osaka in 1912, Yanmar was the first industrial machinery manufacturer in the world to successfully commercialize a compact diesel engine in 1933. In the fields of “land,” “sea,” and “city,” Yanmar is globally expanding its business in agriculture, construction machinery, marine, energy systems, and other fields, centered on engines and other powertrains. Aiming to be an environmentally burden-free and GHG-free company, we provide solutions that create value for our customers. Based on Yanmar’s “HANASAKA” values, which nurture the future, we will realize “A SUSTAINABLE FUTURE” as our brand statement.

For more information, please visit Yanmar’s website at https://www.yanmar.com/jp/about

About Kita-Sanriku Factory

Kita-Sanriku Factory is a leading company developing high-quality sea urchin brands in the town of Hirono, Iwate Prefecture, home to the world’s only “Sea Urchin Farm ®︎”. With the mission of “Enriching the world’s oceans from Kita Sanriku,” the company is leveraging its expertise in raising high-quality sea urchins to connect with the world through its new “sea urchin regenerative aquaculture system” technology and promote initiatives to create a sustainable future for the marine industry. We established an Australian corporation in 2023 and are expanding our business both domestically and internationally.

U R L ：https://kitasanrikufactory.co.jp

In April 2025, KSF Australia Pty Ltd, the Australian subsidiary of Kita-Sanriku Factory Inc., commenced a land-based aquaculture trial with Deakin Marine Research and Innovation Centre, Victoria’s leading marine research institution at Deakin University. The trial uses the Australian “HAGUKUMU-TANE®”, a formulated feed for sea urchins originally co-developed with Associate Prof Ura Kazuhiro of the Graduate School of Fisheries Science at Hokkaido University.

The trial is being conducted at the Deakin Queenscliff Marine Science Centre, located along the coast of Port Phillip Bay in Victoria, Australia. The feed “HAGUKUMU-TANE®,” has been produced using locally sourced Australian ingredients. The trial aims to evaluate its efficacy in the roe enhancement and the quality improvement of malnourished sea urchins.

In recent years, the population of the purple sea urchin (Heliocidaris erythrogramma), a species native to Australia, has dramatically increased in Port Phillip Bay. A 2019/2020 survey estimated that approximately 125 million individuals (around 9,700 tonnes) inhabit the bay*¹. Furthermore, it is reported that at least 60% of reefs in the bay have been impacted by urchin barrens, where overgrazing by sea urchins has led to ecological degradation*². Several areas have already reported the loss of over 90% of their seaweed beds*³, highlighting the urgent need for countermeasures.

To address this issue, KSF Australia established a consortium in 2023 in collaboration with Deakin University, The Nature Conservancy, an international environmental NGO, and Yumbah Aquaculture, Australia’s largest shellfish aquaculture company specialising in abalone, oysters and mussels. This joint experiment is being carried out under the framework of the consortium. We will continue to work collaboratively to establish a new business model that contributes to marine ecosystem restoration and enhances the value of sea urchin resources from urchin barrens, through sustainable and regenerative aquaculture practices in Australia.

*¹Graham, T., Carnell, P., Warren-Myers, F., Morris, R., Swearer, S. (2021) Port Phillip Bay Sea Urchin Survey 2019/2020. Melbourne and Deakin University report.
*²Johnson, C. R., Swearer, S., Ling. S., Reeves, S., Kriegisch, N., Treml, EA., et al. (2015). The Reef Ecosystem Evaluation Framework: Managing for Resilience in Temperate Environments. University of Tasmania. Report. https://hdl.handle.net/102.100.100/495679
*³Carnell, P. E., & Keough, M. J. (2019). Reconstructing historical marine populations reveals major decline of a kelp forest ecosystem in Australia. Estuaries and Coasts, 42(3), 765-778.