Leave a Nest Co., Ltd., Daiken Corporation, and Taisei Namacon Co., Ltd. have begun field trials in the waters of Mitoyo City, Kagawa, to evaluate marine restoration materials under development. The trial is being conducted in cooperation with Mitoyo City and the Takuma Fisheries Cooperative Association, whose members have long worked in the area.
The materials are being developed from naturally derived resources as substrates that support the growth of seaweeds. Through development and future commercialization, the partners aim to contribute to the restoration and conservation of marine organisms and environments and to increase the richness of the ocean.
Background
According to the World Wide Fund for Nature (WWF), 69 percent of the world's biodiversity has been lost over the past 50 years, with the resulting economic loss estimated at 44 trillion US dollars. The decline of marine organisms is particularly serious: reports indicate that their abundance fell by half over the 42 years since 1970.
Coastal environments formed around seaweed beds and seagrass are important for maintaining marine biodiversity. They provide habitats for many marine organisms and are attracting attention as stores of carbon, known as blue carbon. At the same time, changes in nutrients flowing from land and rising seawater temperatures are steadily degrading these environments.
This initiative grew out of work begun in fiscal 2023 by Leave a Nest and Daiken to explore new businesses. While considering co-creation around manufacturing that regenerates and conserves the environment, the partners were joined in summer 2024 by Taisei Namacon, a regional company working on coastal restoration in Mitoyo. Together with the fishers of the Takuma Fisheries Cooperative Association and Mitoyo City, the team is now taking on the challenge of restoring the marine environment.
Field trial overview
Test materials developed by Daiken were installed in the waters of Mitoyo City on January 21, 2025. Multiple types with different structures and compositions were prepared, with the aim of identifying methods that are effective for seaweed growth. During the trial, Taisei Namacon will lead surveys of recovery trends and seaweed-bed formation and analyze the results toward the development of new materials that contribute to marine restoration.
The roles of the participating organizations are as follows: Leave a Nest plans and manages the field trial, Daiken develops the materials, and Taisei Namacon monitors the site after installation.
Comments from the participating organizations
Leave a Nest Co., Ltd.
For Leave a Nest, whose philosophy is to realize the development of science and technology and contribute to the Earth, this development and field trial are exactly the kind of activity that should be advanced through science and technology. Beyond this trial, we will continue to bring together knowledge and technologies from researchers and companies to enrich the ocean in Mitoyo and elsewhere.
Daiken Corporation
For Daiken, which has built its business around building materials, developing marine restoration materials is a first and a new challenge. This field trial was born from co-creation with Taisei Namacon and Leave a Nest and has begun with the cooperation of the Takuma Fisheries Cooperative Association and Mitoyo City. We will continue researching materials that have a positive effect on ecosystems and contribute to environmental restoration by applying the material-development technologies we have cultivated.
Taisei Namacon Co., Ltd.
As a regional company based on the Seto Inland Sea, we cannot ignore the recent deterioration of the marine environment. Although what a small and medium-sized company can do is limited, we were invited by Daiken and Leave a Nest to join this initiative. The deterioration of marine environments and changes in ecosystems are progressing around the world and may no longer be solvable by one organization alone. By combining unique technologies and skills with the wishes of people living in the region to restore the sea, we hope to find a way forward.
Mitoyo City
We are delighted that this initiative has begun to pass Mitoyo's rich marine environment on to the next generation. As seaweed beds decline and marine environments deteriorate, collaboration among local fishers and companies to develop and demonstrate new marine restoration materials is an important step toward protecting and recovering the richness of the sea. We hope the trial will lead to the recovery of marine organisms and environmental improvement and that the initiative will spread to coastal regions across Japan. Mitoyo City will continue to support the project in cooperation with all involved.
Takuma Fisheries Cooperative Association
We want to bring back the Seto Inland Sea that was once rich. With this wish, the Takuma Fisheries Cooperative Association joined the initiative to install trial materials for marine restoration in cooperation with companies, local government, and related organizations. We believe the initiative will support sustainable fisheries and contribute to conserving the local natural environment. We will continue working to pass the blessings of a rich sea on to the next generation.
Sources and terminology
1. WWF, Living Planet Report 2020.
2. World Economic Forum, The Future of Nature and Business (2020).
3. Living Blue Planet Report: Species, habitats and human well-being.
Contact
Leave a Nest Co., Ltd.
Contact: Satoshi Nishiyama, Yuzuru Kodama
TEL: +81-3-5227-4198
Daiken Corporation
Contact: Shigeki Ishiguro, Masaki Tsuji, R&D Center
TEL: +81-86-264-5671
Taisei Namacon Co., Ltd.
Contact: Junya Miyake
TEL: +81-875-83-3010