Effects of inhibition of zoospore dispersal by marine bivalve farming on the formation of marine forests

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05744
• 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: Tohoku University
• Principal Investigator: Aoki Masakazu 東北大学, 農学研究科, 教授 (70251014)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 海中林 / 遺伝構造解析 / メタ個体群 / コンブ目褐藻類 / 近交弱勢 / 養殖筏 / 遊走子 / 遺伝的隔離

Outline of Final Research Achievements

The marine forest of the brown alga Eisenia bicyclis consists of a metapopulation structure with patchy populations as the unit. Isolation by distance between local communities separated by water masses is thought to be linked by low-frequency migratory exchanges of zoospores. In this study, we focused on the possibility that water filtering activity by bivalve molluscs on aquaculture rafts in the bay may prevent migratory exchanges of zoospores between local population patches. The results of genetic structure analysis by SNP detection of E. bicyclis communities at 10 sites in Shizugawa Bay and 8 sites in Onagawa Bay, where large-scale bivalve aquaculture is conducted, were compared with the distribution of bivalve aquaculture rafts in the respective areas. The results suggest that the presence of culture rafts causes genetic isolation and prevents zoospore dispersal despite the short distance between the sites of local population.

Free Research Field

水圏植物生態学

Academic Significance and Societal Importance of the Research Achievements

本研究における遺伝子解析の結果から、二枚貝類の養殖場における濾過摂食活動が褐藻アラメの遊走子分散を妨害することによってアラメの藻場形成に影響を与える可能性が示唆された。これまで、二貝類の養殖業と藻場・海中林の造成事業は、水産学の中でも、別個の学問分野として研究が行われてきた。この両者をつなぎ、その相互影響について検討する必要のあることが、本研究により示された。ここで得られた遺伝子交流の情報をもとに、アラメの局所個体群間の遊走子の交流が可能となるような『遊走子の道』を二貝類養殖場に確保することも可能となるはずである。