Swimming behavior of zooplankton and its dietary value for fish larvae

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H03862
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Nagasaki University
• Principal Investigator: HAGIWARA Atsushi 長崎大学, 水産・環境科学総合研究科(水産), 教授 (50208419)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 養殖 / 種苗生産 / 餌料生物 / ワムシ類 / カイアシ類 / 遊泳行動 / 生理活性物質 / 仔魚

Outline of Final Research Achievements

I conducted a study to improve the health of fish larvae by feeding rotifers with higher activity in their swimming behavior. Using fish waste from Chub mackerel as a food source (FWD), the highest density of rotifers reached to 1190 individuals/mL, and the DHA and EPA contents met the essential levels for the larvae without nutritional enrichment. The density was further increased by adding commercial probiotics, and stable culture was possible by suppressing the increase of free ammonia and harmful bacteria. The average swimming speed of the larvae increased by 25-58%, and the growth of the Japanese whiting larvae tended to be faster when they were fed with FWD-cultured rotifers.

Free Research Field

水産増殖学

Academic Significance and Societal Importance of the Research Achievements

本研究を通じて、栄養状態が良いワムシは、悪環境からの逃避の際に、通常とは異なる大変活発な行動を示すことが明らかになってきた。カイアシ類やミジンコのように、ワムシも不規則で複雑な遊泳行動を示すようにでき、天然餌料に匹敵する餌料価値を付加することが可能と考えられる。世界人口の増加と食料不足が顕在化し、栄養価に優れた魚介類養殖への期待が高まっている。途上国を中心として海面養殖への期待は大きいが、稚魚の生産コストが高いため、普及が遅れている。本研究の経過で付随的に開発に成功したワムシの低コスト培養技術は、途上国の海水養殖の普及に大きく役立つものである。