New paper out in PNAS! Convergence of undulatory swimming kinematics of fishes
Many fishes swim primarily through undulation of their body and caudal fin (BCF) and have been historically divided into 4 major kinematic modes based on their morphology: (a) anguilliform (eel), (b) sub-carangiform (trout), (c) carangiform (mackerel), (d) thunniform (tuna). Figure below from Lindsey (1978) shows these classic modes, where head oscillation decreases from eel to tuna.
In our paper, we analyzed the kinematics of undulatory swimming in 43 fishes (+ amphioxus) across speeds. Despite the morphological diversity of fishes used in our study, we found that fishes share major kinematic features during steady swimming and are placed on a continuum rather than in discrete categories. Even when we analyzed the kinematics of the four representative species for these swimming modes, we found significant overlap. We propose a unifying model that can describe most of the diversity found in BCF 2D undulatory swimming and here is a new view of BCF swimming (B shows the midline kinematics!):
In this study we combined experiments, video analyses, morphological measurements of specimens from the Harvard Museum of Comparative Zoology, and biomechanical modeling.
It’s been a wonderful collaboration with a dream team from Stockholm University, Harvard, University of Florida, Yale and the USGS Conte Lab (MA, USA).
Here is the paper: