Effects of changes in seaweed bed vegetation associated with ocean warming on fish and fisheries

• Project/Area Number: 19K06209
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Kochi University
• Principal Investigator: Nakamura Yohei 高知大学, 教育研究部総合科学系黒潮圏科学部門, 教授 (60530483)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
• Keywords: 藻場 / 魚類 / 温暖化 / 魚類群集 / 地球温暖化

Outline of Research at the Start

西日本では，温暖化の影響を受けて1990年代以降に在来の温帯性海藻の消失や南方系海藻の定着が顕在化している。本研究では，藻場の消失や海藻構成種の変化が魚類群集構造に与える影響を経年観察データから探るとともに，漁獲対象魚種の変化も調べることで，温暖化に伴う藻場植生の変化が魚類と漁業に与える影響を明らかにする。

Outline of Final Research Achievements

This study clarified the effects of the loss of kelp beds and changes in the Sargassum species composition on fish community structure by comparing current and historical data in the Kochi Prefecture, western Japan. In addition, tank experiments revealed that some fish species prefer specific Sargassum species, indicating that change in Sargassum species composition is one factor that alters fish community structure. Furthermore, interviews with fishermen in Kochi Prefecture revealed that the decrease in seaweed beds had a negative impact on artisanal fisheries targeting reef squid and abalone.

Academic Significance and Societal Importance of the Research Achievements

温暖化研究は気候変動に伴う生態系やその関連サービスの変化を予測し，その変化に対する対策や適応策を提示することで社会的課題の解決策を生み出すことを主目的としている。しかし，海藻藻場と魚類群集のつながりの強さに関する国内外の研究がほとんどないため，藻場変化に伴う魚類群集の変化予測に不確実性が伴うことが欠点であった。本研究によって各魚種の藻場に対する依存度が明らかにされたことで，藻場変化による魚類群集の変化予測の精度は格段に向上すると考えられる。

Research Products

• [Journal Article] The value of ecosystem services in global marine kelp forests (2023)
  • Author(s): Aaron M. Eger, Ezequiel M. Marzinelli, Rodrigo Beas-Luna, et al.
  • Journal Title: Nature Communications Volume: 14 Issue: 1 Pages: 1894-1894
  • DOI: 10.1038/s41467-023-37385-0
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Differences in fish herbivory among tropical and temperate seaweeds and annual patterns in kelp consumption influence the tropicalisation of temperate reefs (2022)
  • Author(s): Verges A, Lanham BS, Kono M, Okumura S, Nakamura Y.
  • Journal Title: Scientific Reports Volume: 12 Issue: 1 Pages: 21202-21202
  • DOI: 10.1038/s41598-022-24666-9
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Homogenization and miniaturization of habitat structure in temperate marine forests (2021)
  • Author(s): Pessarodona A, Filbee-Dexter K, Alcoverro T, Boada J, Feehan C, Fredriksen S, Grace S, Nakamura Y, Narvaez C, Norderhaug KM, Wernberg T
  • Journal Title: Global Change Biology Volume: 27 Issue: 20 Pages: 5262-5275
  • DOI: 10.1111/gcb.15759
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Unpredictable extreme cold events: a threat to range-shifting tropical reef fishes in temperate waters (2019)
  • Author(s): Leriorato JC, Nakamura Y
  • Journal Title: Marine Biology Volume: 166 Issue: 8 Pages: 1-10
  • DOI: 10.1007/s00227-019-3557-6
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 四国西部におけるガラモ場の魚類群集構造の緯度間比較と魚類の海藻選好性 (2022)
  • Author(s): 土居真大・中村洋平
  • Organizer: 令和4年度日本水産学会中国・四国支部例会
• [Presentation] 土佐湾におけるガラモ場の海藻構成種の変化が魚類群集の構造に与える影響 (2022)
  • Author(s): 土居真大・中村洋平
  • Organizer: 令和4年度日本水産学会春季大会
• [Presentation] 土佐湾の流れ藻の海藻構成種とブリ稚魚数：10年前と現在の比較 (2022)
  • Author(s): 西脇宙生・中村洋平・田中幸記
  • Organizer: 令和4年度日本水産学会春季大会