Document Type

Article

Publication Date

2-2019

DOI

10.1242/jeb.200634

Publication Title

Journal of Experimental Biology

Volume

222

Issue

3

Pages

jeb.200634 (16 pp.)

Abstract

Squid, which swim using a coupled fin/jet system powered by muscular hydrostats, pose unique challenges for the study of locomotion. The high flexibility of the fins and complex flow fields generated by distinct propulsion systems require innovative techniques for locomotive assessment. For this study, we used proper orthogonal decomposition (POD) to decouple components of the fin motions and defocusing digital particle tracking velocimetry (DDPTV) to quantify the resultant 3D flow fields. Kinematic footage and DDPTV data were collected from brief squid, Lolliguncula brevis [3.1–6.5 cm dorsal mantle length (DML)], swimming freely in a water tunnel at speeds of 0.39–7.20 DML s−1. Both flap and wave components were present in all fin motions, but the relative importance of the wave components was higher for arms-first swimming than for tail-first swimming and for slower versus higher speed swimming. When prominent wave components were present, more complex interconnected vortex ring wakes were observed, while fin movements dominated by flapping resulted in more spatially separated vortex ring patterns. Although the jet often produced the majority of the thrust for steady rectilinear swimming, our results demonstrated that the fins can contribute more thrust than the jet at times, consistently produce comparable levels of lift to the jet during arms-first swimming, and can boost overall propulsive efficiency. By producing significant drag signatures, the fins can also aid in stabilization and maneuvering. Clearly, fins play multiple roles in squid locomotion, and when coupled with the jet, allow squid to perform a range of swimming behaviors integral to their ecological success.

Comments

This project was supported by the National Science Foundation (IOS 1115110 and IOS 1557669 to I.K.B., P.S.K. and J.T.T.).

There was an error published in Journal of Experimental Biology (2018) 221, jeb176750 (doi:10.1242/jeb.176750).

Rights

Open access article

© 2019. Published by The Company of Biologists Ltd

Original Publication Citation

Bartol, I. K., Krueger, P. S., York, C. A., & Thompson, J. T. (2019). New approaches for assessing squid fin motions: Coupling proper orthogonal decomposition with volumetric particle tracking velocimetry (Vol 221, jeb176750, 2018). Journal of Experimental Biology, 222(3), jeb.200634. doi:10.1242/jeb.200634

ORCID

0000-0001-9006-8727 (Bartol)

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