Energy-saving in schooling Japanese mackerel (<i>Scomber japonicus</i>) and the effect of induced velocity of wake vortices

• Takagi Tsutomu

  Faculty of Fisheries Sciences, Hokkaido University

• Ito Shizuka

  Faculty of Agriculture, Kindai University

• Torisawa Shinsuke

  Faculty of Agriculture, Kindai University

• Inada Yoshinobu

  Faculty of Engineering, Tokai University

Abstract

A constrained swimming test showed that at fastest flow speeds, the tail-beat frequencies (TBF) of followers in a school of Japanese chub mackerels were significantly lower than those of the leading fish. The gross cost of transport (GCOT) of schooling fish was 4.8-6.6 J·kg^-1·m^-1, whereas that of solitary swimming fish was significantly larger (9.2-11.5 J·kg^-1·m^-1). To examine the association between the configuration of individuals in the school and energy-saving, the three-dimensional positions of individuals in a school were measured in a large tank. Although the school was not arranged in the diamond pattern known to be most effective for energy conservation, the TBF of the followers remarkably decreased when within the range of 1.4 BL (Body Length) from the leading fish in the school. The energy gain of schooling fish was greater than that derived from the potential-theory basis, implying a potential hydrodynamic synergy effect.

Journal

• Journal of Aero Aqua Bio-mechanisms

  Journal of Aero Aqua Bio-mechanisms 4 (1), 78-82, 2015

  Society of Aero Aqua Bio-mechanisms

Keywords

• school
• mackerel
• energy-saving
• cost of transport

Details

• CRID: 1390001205342048512
• NII Article ID: 130005109545
• DOI: 10.5226/jabmech.4.78
• ISSN: 21851522
• Web Site: https://www.jstage.jst.go.jp/article/jabmech/4/1/4_78/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed