Three-dimensional shape analysis of flexible pectoral fins in turn swimming motions of goby

Abstract

Gobies achieve hovering and agile swimming such as sudden turn from a stationary state, sudden acceleration, and sudden stop by using pectoral fins. The motion and deformation of their pectoral fins seems to be different from the conventional classification of swimming forms in fish. Understanding the swimming mechanism of a goby can inspire new fish-mimetic swimming robots fully utilizing pectoral fins. In this study, we attached fluorescent markers to a goby and recorded right turns with multiple video cameras, followed by three-dimensional motion analysis to quantify bending deformation of the pectoral fins during downstroke. As a result, it was found that the left pectoral fin notably bent, while the bending of the right pectoral fin was smaller than the left fin.