Research on the habitat environment, ecology, and taxonomy of the endangered mollusks,Onchidium sp. A

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06184
• 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: Ehime University
• Principal Investigator: Takagi Motohiro 愛媛大学, 南予水産研究センター, 教授 (70335892)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ドロアワモチ / Onchidium sp. A / 絶滅危惧貝類 / 保全 / 生態

Outline of Final Research Achievements

The Doroawamochi (Onchidium sp. A) was uncovered on the dried tidal flats during April to November. Feeding behavior was observed after the tidal flats began to dry out, and the observed number of individuals tended to be the highest within 2 hours before and after the lowest tide. Similar activities were observed at low tide at night. The number of appearing individuals decreased in rainy weather. Internal morphology of Doro-awamochi and Jacoten-awamochi revealed no differences in the way the intestinal tract, the male reproductive organs, and the radula. When breeding of Onchidium sp. A was attempted, the production of egg masses was confirmed. The egg size was about 160 μm, the number of eggs in the egg mass was estimated to be about 7800, and the hatched larvae were of the veliger type.

Free Research Field

水圏生産科学

Academic Significance and Societal Importance of the Research Achievements

腹足綱収眼目アワモチ科貝類のドロアワモチは内湾の干潟の一部に生息し、干潮時には干潟を匍匐、表面のデトリタス等を摂食し、満潮時には砂泥中に潜り込むとされる。本種は環境省または各自治体のレッドデータブック等に絶滅危惧種として記載されている。絶滅危惧種の保全において、保全対象種についての基礎的情報となる生息環境および生態の把握が重要であるが、ドロアワモチについては生息適地の環境や生態に関する研究は行われていない。本研究では、ドロアワモチ生息地における生態・飼育観察および形態学的・遺伝学的解析を行い、ドロアワモチの生態の解明および種の確定にむけた作業を行った。