PT  - JOURNAL ARTICLE
AU  - Cees J. Voesenek
AU  - Gen Li
AU  - Florian T. Muijres
AU  - Johan L. van Leeuwen
TI  - Fish larvae tackle the complex fluid-structure interactions of undulatory swimming with simple actuation
AID  - 10.1101/736587
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 736587
4099  - http://biorxiv.org/content/early/2019/08/15/736587.short
4100  - http://biorxiv.org/content/early/2019/08/15/736587.full
AB  - Most fish swim with body undulations that result from fluid-structure interactions between the fish’s internal tissues and the surrounding water. As just-hatched larvae can swim effectively without a fully-developed brain, we hypothesise that fish larvae tackle the underlying complex physics with simple actuation patterns. To address this hypothesis, we developed a dedicated experimental-numerical approach to calculate the lateral bending moment distributions, which represent the system’s net actuation. The bending moment varies over time and along the fish’s central axis due to muscle actions, passive tissues, inertia, and fluid dynamics. Our 3D analysis of a large dataset of swimming events of larvae from 3 to 12 days after fertilisation shows that these bending moment patterns are not only relatively simple but also strikingly similar throughout early development, and from fast starts to periodic swimming. This suggests also similar muscle activation patterns, allowing fish larvae to produce swimming movements relatively simply, yet effectively, while restructuring their neuromuscular control system.