New article: Significant changes in seaweed community structure revealed by a nationwide long-term monitoring survey in Japan “Monitoring-Site 1000” over the past 15 years (2008–2022)

Please take a look at our new review article on the nationwide long-term monitoring program in Japan, “Monitoring-Site 1000,” which summarizes 15 years of surveys (2008–2022) and reveals significant changes in seaweed community structure, including the disappearance of kelp forests. Since the article is open access, anyone can download it from the website. The website also provides extensive supplementary materials, including many beautiful underwater photos taken during the surveys—please don’t miss them.

 

R. Terada, T. Abe, S. Akita, M. Kamiya, H. Kawai, A. Kurashima, C. Nagasato, Y. Sakanishi, H. Shimabukuro, H. Suzuki, J. Tanaka, S. Uwai, Y. Watanabe, R. Ueno, M. Aoki 2026. Significant changes in seaweed community structure revealed by a nationwide long-term monitoring survey in Japan “Monitoring-Site 1000” over the past 15 years (2008–2022).

Phycological Research 74 (1): 39–56 

 

https://doi.org/10.1111/pre.70019 (Online: 8 December 2025; Issue: January 2026)

https://onlinelibrary.wiley.com/doi/10.1111/pre.70019

https://doi.org/10.1111/pre.70019

 

New article: First record of Ulva kanagawae from Ogasawara Islands, Japan

Please take a look at our new article reporting the first record of Ulva kanagawae V. Carneiro, N. T. Martins & Cassano from Chichi-jima in the Ogasawara (Bonin) Islands, Japan. This alga was described as a new species in 2023, but the type locality was São Paulo, Brazil. Our finding represents the first record of this species from the Pacific Ocean. Because the biogeographic connection between Ogasawara and São Paulo remains unclear, we are very excited to see future records that may further clarify the distribution of this alga.

Kitayama, Suzuki, Terada 2025.
First record of Ulva kanagawae V.Carneiro, N.T.Martins & Cassano (Ulvales, Chlorophyta) from Japan.
Bulletin of the National Museum of Nature and Science. Series B, Botany 51 (4): 127–135
DOI: 10.50826/bnmnsbot.51.4_127

https://www.jstage.jst.go.jp/article/bnmnsbot/51/4/51_127/_article/-char/ja

Congratulations to Dr. Taiju Kitayama, National Museum of Nature and Science, on his great work!  

New article: Thorea okadae

Our new article, which elucidates the photosynthetic response of the freshwater red alga Thorea okadae to environmental gradients of temperature, irradiance, desiccation, and salinity, was recently published in the Journal of Applied Phycology. Thorea okadae is a freshwater red alga distributed in the southern and western parts of Japan and is listed as an endangered species by the Ministry of the Environment of Japan. We believe that the insights presented in the article will contribute to a better understanding of the conservation of this species.

Terada, Makino, & Nishihara 2025. The photosynthetic response of the freshwater red alga Thorea okadae to environmental gradients of temperature, irradiance, desiccation, and salinity: Adaptations to its stream habitat. Journal of Applied Phycology, 37. https://doi.org/10.1007/s10811-025-03528-7

https://link.springer.com/article/10.1007/s10811-025-03528-7 

Thorea okadae

Research voyage of the T/S Nansei-Maru, Kagoshima University

The Marine Botany Lab and Kagoshima City Aquarium participated in a research voyage aboard the T/S Nansei-Maru of Kagoshima University, conducting a deep subtidal algal survey off the coast of Tanegashima Island in the northern Ryukyu Islands. The weather and sea conditions were calm, and we successfully returned to Kagoshima today. This survey was conducted as part of a training voyage for university students in the Faculty of Fisheries.

 

Nationwide long-term monitoring of algal communities

As part of a collaboration between our lab and the algal lab at Kobe University, Professor Terada and an MSc student participated in field surveys for the nationwide long-term monitoring of algal communities, which was conducted by Kobe University. During two surveys—at Awajishima Island and Takeno—dense communities of Ecklonia and Sargassum spp. were confirmed.

Kobe University Marine Site at Awajishima Island

Ecklonia cava

Takeno Site

Sargassum spp.

 

論文：分布南限の褐藻アントクメ：消失したと思われていた鹿児島県馬毛島沖での再確認

研究室の新しい論文が植物研究雑誌より刊行されました。

 

寺田竜太 2024．分布南限の褐藻アントクメ：消失したと思われていた鹿児島県馬毛島沖での再確認．

植物研究雑誌99 (4): 273–279

DOI: 10.51033/jjapbot.ID0211（刊行日：2024年8月20日）

 

Ryuta Terada 2024. A brown alga, Ecklonia radicosa at the southernmost distributional limit in Japan: Reconfirmation of Ecklonia radicosa from Mageshima Island, Kagoshima, the southernmost distributional limit in Japan. 

The Journal of Japanese Botany 99 (4): 273–279

DOI: 10.51033/jjapbot.ID0211 (Issue: 20 August 2024)

 

https://www.jstage.jst.go.jp/article/jjapbot/99/4/99_ID0211/_article/-char/ja

 

褐藻アントクメEcklonia radicosa（コンブ目）の標本や記録における分布南限は，種子島の西方に位置する馬毛島沖ですが，1971年の標本以降生育が確認されないままでいました。本種は馬毛島周辺海域から消失した可能性が考えられてきましたが，2023年10月7日の調査航海で実施したドレッジ調査において，本種の生育が改めて確認されました。

 

植物研究雑誌の論文のダウンロードは，刊行から2年間は雑誌購読者に限られています（2年以上を経たものはオープンアクセス）。論文に関心のある方は，お気軽に我々にお問い合わせください。なお，植物研究雑誌は2025年の刊行100周年に併せ，電子媒体のみによる完全オープンアクセスに移行するそうです。

The Takeno and Awajishima surveys

We participated in field surveys for the nationwide long-term monitoring project known as 'Monitoring Site 1000,' conducted at Takeno in Toyooka City, facing the Sea of Japan, and at Awajishima Island in Sumoto City, facing the Pacific Ocean, both located in Hyogo Prefecture.

 

 

These surveys were conducted by the Kobe University Research Center of Seto Inland Seas (KURCIS), and phycologists from the Japan Fisheries Research and Education Agency, as well as those from our laboratory, were invited as specialists.
 

Sargassum horneri at Nagashima Island, Kagoshima

Introducing amazing photos of the fucoid forest, Sargassum hornei, found only during this period at Nagashima Island, Kagoshima, Japan. The photos were taken during the April Nagashima survey.

 

論文：鹿児島湾のアマモ場が2006年と比べて1/10に減少

近年，日本各地で藻場の衰退や消失が報告されています。私たちの研究室が2021年に鹿児島湾の海草藻場（アマモ場）を広域調査した結果，2006年と比べて約10分の1に減少していることが明らかになりました。

新北成実，寺田竜太．2023．鹿児島湾のアマモ場：2021年の分布状況と長期的な衰退．

日本水産学会誌

DOI: 10.2331/suisan.23-00020

https://doi.org/10.2331/suisan.23-00020

無料でダウンロードできます。

 

鹿児島湾のアマモ場（鹿児島市）

 

New article: Density regulation of aquaculture production and its effects on commercial profit and quality as food in the cosmopolitan edible seaweed Undaria pinnatifida

Please take a look at our new article, which discusses the regulation of aquaculture production density and its impact on commercial profitability and food quality of the cosmopolitan edible seaweed, Undaria pinnatifida.

Yoichi Sato, Takayuki Fujiwara, Hikaru Endo 2023. Density regulation of aquaculture production and its effects on commercial profit and quality as food in the cosmopolitan edible seaweed Undaria pinnatifida. Frontiers in Marine Science 10: 1085054 DOI: 10.3389/fmars.2023.1085054

https://www.frontiersin.org/articles/10.3389/fmars.2023.1085054/full

 

論文：海草ウミショウブEnhalus acoroidesの光合成活性の日周変化

熱帯性の海産顕花植物であるウミショウブEnhalus acoroidesの光合成活性の日周変化を測定した論文が出ました。

島田菜摘，Gregory N. Nishihara，寺田竜太．2022．自然光下の測定によるウミショウブの光合成光化学効率の日変化．水産増殖70 (3): 277–280

Natsumi Shimada, Gregory N. Nishihara, Ryuta Terada. 2022. Diurnal change of the photochemical efficiency in a seagrass, Enhalus acoroides, based on the measurement under incident sunlight. Aquaculture Science 70 (3): 277–280

https://researchmap.jp/ryuta-terada/published_papers/41188424

Enhalus acoroides

New article: Sargassum macrocarpum

Our new and last article in 2022 was out online. Please check out the following article featuring “the effect of temperature, light-spectrum, desiccation, and salinity gradients on the photosynthetic performance of a subtidal brown alga, Sargassum macrocarpum from Japan.

Ito, Yoshioka, Shimabukuro, Nishihara, Endo, Terada 2023. The effect of temperature, light-spectrum, desiccation, and salinity gradients on the photosynthetic performance of a subtidal brown alga, Sargassum macrocarpum from Japan. Phycological Research DOI: 10.1111/pre.12508

https://onlinelibrary.wiley.com/doi/full/10.1111/pre.12508

Sargassum macrocarpum

論文：アマモZostera marinaの分布南限個体群の光合成における温度や光の影響

鹿児島湾に生育する海産顕花植物アマモZostera marinaの分布南限個体群の光合成における温度や光の影響に関する論文が刊行されました。

 

島田菜摘，畳谷伊織，Gregory N. Nishihara，寺田竜太．2022．

鹿児島産一年生アマモZostera marina実生の光合成に対する温度や光の影響．

日本水産学会誌88 (6): 早期公開（2022年11月11日）

DOI: 10.2331/suisan.22-00011

 

Natsumi Shimada, Iori Tatamidai, Gregory N. Nishihara, Ryuta Terada. 2022.

The effect of temperature and light on the photosynthesis of annual Zostera marina seedlings from Kagoshima, Japan.

Nippon Suisan Gakkaishi 88 (6):

DOI: 10.2331/suisan.22-00011

 

https://www.jstage.jst.go.jp/article/suisan/advpub/0/advpub_22-00011/_article/-char/ja

 

 

T/S Nansei-Maru Tokara Islands Survey: Gaja-jima Island

 As the second research voyage of the T/S Nansei-Maru for our lab in May, we conducted the Tokara Islands survey featuring an uninhabited island, Gaja-jima island, northern Ryukyu Archipelago. This is the collaboration survey of the Marine Ecology, Ichthyology, and Marine Botany labs at Kagoshima University.

Underwater view of the off of Gaja-jima Island

Gaja-jima Island

Kogaja-jima Island

Gaja-jima Island

Caulerpa filicoides

T/S Nansei-Maru, Kagoshima University

A view of Yakushima-Island, from T/S Nansei-Maru

 

Sargassum horneri and Ecklonia aridoca in Nagashima island

Introducing some nature photos of seaweed communities from the field survey in Nagashima Island, Kagoshima. Spring has sprung! 

Sargassum horneri 

Ecklonia aridoca

Sargassum horneri

Sargassum horneri

Ecklonia aridoca

 

Annual kelp survey

Prof Ryuta Terada (Marine Botany Lab) attended an annual survey for the long-term monitoring of kelp assemblages in Muroran, Hokkaido, Japan. It was conducted in collaboration with the Hokkaido University Muroran Marine Station and our lab.

Saccharina japonica

Study site

Alaria crassifolia

The last survey of 2017

Temperate Sargassum forest @ Takeno, Hyogo Prefecture, Japan (23 Dec 2017)
It was the last field survey in 2017. Wishing you a festive holiday season and a very happy new year.

種子島沖の調査航海

鹿児島大学水産学部附属練習船南星丸に乗船し，種子島の沖合で調査をおこないました。海藻類の調査は海岸線に近い場所が一般的ですが，南西諸島の周辺は透明度が高く，水深40m付近でも海藻が多く生育しています。調査では，水深40m付近の海藻をドレッジで採集したり，採泥器で微細藻類を採取しました。また，CTDを使って水中の光量と温度を測定しました。毎年実施している本調査から，以下の論文が最近公表されています。

Horiguchi, T., Moriya, R., Pinto, S. K., Terada, R. 2017. Pyramidodinium spinulosum sp. nov. (Dinophyceae), a sand-dwelling non-motile dinoflagellate from the seafloor (36 m deep) off Mageshima Island, Kagoshima, Japan. Phycological Research 65(4): DOI: 10.1111/pre.12183
http://onlinelibrary.wiley.com/d…/10.1111/pre.12183/abstract

Borlongan, I. A., Nishihara, G. N., Shimada, S., Terada, R. 2017. Photosynthetic performance of the red alga Solieria pacifica (Solieriaceae) from two different depths in the sublittoral waters of Kagoshima, Japan. Journal of Applied Phycology DOI: 10.1007/s10811-017-1209-0
https://link.springer.com/article/10.1007/s10811-017-1209-0

ドレッジの様子

神戸大，福井県立大，水産大学校，瀬戸内海区水産研究所，鹿児島大が淡路島と竹野で共同調査を実施

神戸大，福井県立大，水産大学校，瀬戸内海区水産研究所，鹿児島大の藻類研究者が合同で海藻生育調査を兵庫県の淡路島と竹野で行いました。環境省のモニタリング調査です。

アカモク

カジメ

タマハハキモク

New article! E ucheuma denticulatum and K appaphycus alvarezii from Sulawesi Utara, Indonesia

New paper was out from Phycological Research - Check it out !
Congratulation to Iris and co-authors on this excellent article!

Iris Ann G. Borlongan, Grevo S. Gerung, Gregory N. Nishihara, Ryuta Terada
Light and temperature effects on photosynthetic activity of E ucheuma denticulatum and K appaphycus alvarezii (brown and green color morphotypes) from Sulawesi Utara, Indonesia
Phycological Research DOI: 10.1111/pre.12155

http://onlinelibrary.wiley.com/doi/10.1111/pre.12155/full