In-line swimming dynamics revealed by fish interacting with a robotic mechanism

Abstract
Data availability
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Abstract

Schooling in fish is linked to a number of factors such as increased foraging success, predator avoidance, and social interactions. In addition, a prevailing hypothesis is that swimming in groups provides energetic benefits through hydrodynamic interactions. Thrust wakes are frequently occurring flow structures in fish schools as they are shed behind swimming fish. Despite increased flow speeds in these wakes, recent modeling work has suggested that swimming directly in-line behind an individual may lead to increased efficiency. However, only limited data are available on live fish interacting with thrust wakes. Here we designed a controlled experiment in which brook trout, Salvelinus fontinalis, interact with thrust wakes generated by a robotic mechanism that produces a fish-like wake. We show that trout swim in thrust wakes, reduce their tail-beat frequencies, and synchronize with the robotic flapping mechanism. Our flow and pressure field analysis revealed that the trout are interacting with oncoming vortices and that they exhibit reduced pressure drag at the head compared to swimming in isolation. Together, these experiments suggest that trout swim energetically more efficiently in thrust wakes and support the hypothesis that swimming in the wake of one another is an advantageous strategy to save energy in a school.

Data availability

Data that support the findings of this study are available on:https://doi.org/10.6084/m9.figshare.c.6093405https://gitlab.com/robintha/052-matlab-midline-annotationhttps://github.com/basilisklizard/fluid-structure-segmentation

The following data sets were generated

1. Thandiackal R
2. Lauder GV
(2022) Data and Movies - In-line swimming dynamics revealed by fish interacting with a robotic mechanism
figshare.

https://doi.org/10.6084/m9.figshare.c.6093405

Article and author information

Author details

Robin Thandiackal

Harvard University, Cambridge, United States

For correspondence
rthandiackal@fas.harvard.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-8201-4892
George Lauder

Harvard University, Cambridge, United States

For correspondence
glauder@oeb.harvard.edu

Competing interests
The authors declare that no competing interests exist.

Funding

National Science Foundation (EFRI-830881)

George Lauder

Office of Naval Research (N00014-18-1-2673)

George Lauder

Office of Naval Research (N00014-14-1-0533)

George Lauder

Office of Naval Research (N00014-21-1-2210)

George Lauder

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: All experiments were performed in accordance with Harvard animal care and use guidelines, IACUC protocol number 20-03-3 to George V. Lauder.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.