Elucidation of food resources for the conservation of endangered freshwater bivalves (Unionoida)

2016 Fiscal Year Final Research Report

• Project/Area Number: 25290084
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Conservation of biological resources
• Research Institution: Center for Environmental Science in Saitama
• Principal Investigator: Tanaka Hitoshi 埼玉県環境科学国際センター, 水環境担当, 担当部長 (40415378)
• Co-Investigator(Kenkyū-buntansha): 田中 大祐 富山大学, 理工学研究部(理学), 教授 (40360804) ; 酒徳 昭宏 富山大学, 理工学研究部(理学), 助教 (20713142)
• Co-Investigator(Renkei-kenkyūsha): NISHIMURA OSAMU 東北大学, 大学院工学研究科, 教授 (80208214) ; FUJIBAYASHI MEGUMU 秋田県立大学, 生物資源科学部, 助教 (70552397) ; KAWACHI MASABOBU 国立環境研究所, 生物・生態系環境研究センター, 室長 (80311322)
• Research Collaborator: NISHIO MASAKI 氷見市教育委員会, 主任学芸員
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: イシガイ類 / 希少淡水二枚貝 / 餌資源 / 遺伝子解析 / 必須脂肪酸 / 生息環境 / タナゴ類 / 人工飼料

Outline of Final Research Achievements

Freshwater bivalves (Unionoida) help maintain river ecosystems by acting as host shells for Japanese bitterlings and purifying water by removing suspended matter. Habitats and populations of bivalves have decreased throughout Japan, making protection measures urgent.
Surveys of rivers with high densities of Unio douglasiae nipponensis showed that the microalgae they feed on were in sufficient supply during the warm water period, which marks the bivalve growing season. Analysis of essential fatty acids, that cannot be synthesized in the body and originate from the natural diet, showed that U. douglasiae nipponensis assimilate green algae and diatoms as well as bacteria. Based on these results, we conducted feeding experiments on U. douglasiae nipponensis using cultured and commercial algae, and achieved successful long-term breeding.

Free Research Field

環境生物学