Development of an Acoustic Biomass Estimation Method and Spatiotemporal Distribution Variation of Myctophid fishes in the Temperate Zone of Japan

2024 Fiscal Year Final Research Report

• Project/Area Number: 20K06200
• 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: Hokkaido University
• Principal Investigator: Hiroki Yasuma 北海道大学, 水産科学研究院, 教授 (50517331)
• Co-Investigator(Kenkyū-buntansha): 木村 暢夫 北海道大学, 水産科学研究院, 教授 (50186326) ; 前川 和義 北海道大学, 水産科学研究院, 助教 (80250504) ; 高橋 勇樹 北海道大学, 水産科学研究院, 准教授 (00761701)
• Project Period (FY): 2020-04-01 – 2025-03-31
• Keywords: ハダカイワシ類 / 計量魚群探知機 / 中深層性魚類 / 生物量推定

Outline of Final Research Achievements

The objective of this project was to enable biomass estimation of the dominant mesopelagic fish group in the temperate Pacific Ocean in Japan using acoustic techniques, and to determine the composition and biomass of the dominant fish species using acoustic-trawl surveys. In particular, the southeastern Hokkaido and Kagoshima Bay areas were used as model areas for this project. The target strength of dominant species was estimated and applied to acoustic surveys in the field to estimate species composition, distribution density in relation to geographical conditions, biomass, and the scale of diurnal vertical migration in the area. To enable wider application, biological samples obtained in the Emperor Seasan area were used as a supplement to clarify the scale factor of acoustic reflections.

Free Research Field

水中音響計測

Academic Significance and Societal Importance of the Research Achievements

外洋で最も生物量の多い魚類群であるハダカイワシ類の定量情報は、海洋生態系の深い理解に欠かせないものである。本研究では海洋環境の変化に応じ、優占種の魚種組成や空間分布、生物量が年単位で大きく変動することを示した。有用魚種の資源変動を説明する上での一要因として、重要な餌生物である中深層性魚類の資源量変動やその機構を明示したことは、大変意義深い。