Dynamical analysis reveals individuality of locomotion in goldfish

Abstract

Goldfish swimming was analysed quantitatively to determine if it exhibits distinctive individual spatiotemporal patterns. Due to the inherent variability in fish locomotion, this hypothesis was tested using five nonlinear measures, complemented by mean velocity. A library was constructed of 75 trajectories, each of 5·min duration, acquired from five fish swimming in a constant and relatively homogeneous environment. Three nonlinear measures, the 'characteristic fractal dimension' and 'Richardson dimension', both quantifying the degree to which a trajectory departs from a straight line, and 'relative dispersion', characterizing the variance as a function of the duration, have coefficients of variation less than 7%, in contrast to mean velocity (30%). A discriminant analysis, or classification system, based on all six measures revealed that trajectories are indeed highly individualistic, with the probability that any two trajectories generated from different fish are equivalent being less than 1%. That is, the combination of these measures allows a given trajectory to be assigned to its source with a high degree of confidence. The Richardson dimension and the 'Hurst exponent', which quantifies persistence, were the most effective measures.

Variation of Linear and Nonlinear Parameters in the Swim Strokes According to the Level of Expertise

“…Therefore as far as one is concerned, the dv is a linear parameter that is sensitive to the expertise level in swimming. That said, the selection of multiple nonlinear measures including linear parameters enhances the behavioral discriminations, allowing a better understanding of different motor behaviors, and should not be disregarded (Neumeister et al, 2004).…”

“…The more classical and more mainstream procedures may not be sensitive and insightful enough. Under this framework, it is advised that the selection of a couple of nonlinear measures concurrent to a linear parameter (e.g., for this case the dv) can have a more comprehensive understanding of the different motor behaviors (Neumeister, Cellucci, Rapp, Korn, & Faber, 2004). Yet, only a few papers can be found in the literature reporting nonlinear parameters in sportsmen or sports techniques.…”

Quantitative characterization of animal behavior following blast exposure

“…Quantitative characterization of animal locomotion does not need to be limited to measures derived from symbolic dynamics. A nonlinear analysis of fish movement using the characteristic fractal dimension, the Richardson dimension, the Hurst coefficient, and relative dispersion in addition to Lempel-Ziv complexity has been published by Neumeister et al (2004).…”

The changes in fractal dimension after a maximal exertion in swimming

“…Comparing human swimming with other animals more adapted to aquatic environment, it is easy to follow that the fractal properties would be rather different. Gold fish show an FD of 1.62 [11]. Animals that are more adapted to aquatic environment may be prone to have a lower FD.…”