Análise multifractal do contorno de otólitos como indicador do metabolismo de peixes

Abstract

The otoliths have the property of storing ecological and biological information related to the life history of fish species. Frequently called "black box" of fishes, their richness of information has attracted more and more attention from researchers. Besides the natural biological growth, otoliths also undergo changes in their shape caused by the environment and the habit of fishes. In this sense, it is expected that the complexity of the otolith shape, at a given instant of time, may reveal to us diverse characteristics related to fish metabolism, in particular, characteristics intrinsic to the time of capture. In this work, a study of the otolith contour fluctuations of five distinct species, namely: Mugil curema, Haemulon plumierii, Hyporhampus unifasciatus, Ocyurus chrysurus and Epinephelus marginatus, was performed using the “Traveling Observer” Multifractal Detrended Fluctuation Analysis (MF-DFA) applied to an angular series composed of the distances of the center of mass of this structure to each point that compose its contour. Based on this analysis, correlations of the multifractal complexity parameter 𝛼0 with biological characteristics of the studied species were observed, in particular, the evidence of length of first sexual maturation (𝐿50), migration and approximate correlations of this parameter with the von Bertalanffy growth parameters.