Predicted Recruitment Levels of Japanese Sand Lances Based on the Physiological Factors of Estivation and Reproductive Skips

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K15325
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Aquatic life science
• Research Institution: Kitasato University
• Principal Investigator: AMIYA NORIKO 北里大学, 海洋生命科学部, 講師 (20588503)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: 繁殖スキップ

Outline of Final Research Achievements

The Japanese sand lance, genus Ammodytes, catch has decreased in recent years, and the introduction of effective resource management plans is becoming a pressing issue. This study focused on the estivation that is vital to the Ammodytes’s maturation and its “reproductive skips,” where reproduction is postponed for the year due to an organism’s nutritional status. The study then attempted to establish a method for predicting resource dynamics using physiological factors as indices. The study suggests that the age of maturity of Ammodytes inhabiting the Japanese coast varies widely over their ocean habitat; that they undergo reproductive skips influenced by water temperature; and that this influence varies by region. It is therefore clear that in order to introduce an effective resource management plan, the differences in reproductive ecology by ocean region must be examined in detail, and plans targeting the Ammodytes inhabiting each region must be formulated.

Free Research Field

魚類生理学

Academic Significance and Societal Importance of the Research Achievements

繁殖スキップに関する研究は，生殖腺の観察による成熟度合の確認に留まっている．そのため，動態予測で重要な“いつ，どのような条件で”個体が繁殖スキップを決定するかは不明である．
繁殖を促進するべきか否の判断は，魚類だけではなく，生物の生活史において，種の存続に重要な決断である．したがって，本研究により解明される，生理学的指標を用いた繁殖スキップ発生メカニズムの解明は，あらゆる生物にとって重要な，生存と繁殖のトレードオフ，つまり，“繁殖コストの発生機構の解明”にも繋がる可能性を秘めている.