Study on trophic cascade and establishment of macroalgal beds resilient to ocean warming

2016 Fiscal Year Final Research Report

• Project/Area Number: 26450251
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Fisheries Research and Education Agency
• Principal Investigator: Kawmata Shigeru 国立研究開発法人水産研究・教育機構, 水産工学研究所, グループ長 (50372066)
• Research Collaborator: TAINO SEIYA 高知県水産試験場, 主任研究員 ; TANKA KOUKI 高知大学, 技術職員
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 栄養カスケード / 藻場 / 磯焼け / 禁漁区 / 海洋保護区 / 捕食 / イセエビ / ウニ

Outline of Final Research Achievements

Macroalgal beds have been shifted to sea urchin-dominated barrens around the world. Numerous overseas studies have described that such phase shifts are primarily attributed to overfishing sea-urchin predators. We presented the first case study in Japan, demonstrating the importance of predator-sea urchin-macroalgae trophic cascade in maintaining macroalgal beds on Kochi coast in which marked ocean warming has occurred. Field studies in a fisheries protected area (FPA) and its adjacent control fishing area (FA) showed that, the Japanese spiny lobster was abundant and sea urchin density was reduced by its predation especially near its shelters in the FPA, while sea urchins were highly abundant due to lower predation pressure in the FA. Laboratory studies showed that predation by lobsters on sea urchins differed with size of sea urchins relative to lobsters and with urchin species. Findings of the selective predation agreed with species and size compositions of sea urchins in the field.

Free Research Field

岩礁生態