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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Mar. Sci. | doi: 10.3389/fmars.2019.00728

Peeling the otolith of fish: optimal parameterization for micro-CT scanning

 Jonas E. Vasconcelos-Filho1, 2,  Felix S.L. Thomsen3, Borko Stosic1, 4, Antonio C. Antonino5, Daniel A. Duarte5, Richard J. Heck6,  Rosangela P. Lessa7, Francisco M. Santana8, Beatrice P. Ferreira2 and  Paulo J. Duarte-Neto1, 4*
  • 1Federal Rural University of Pernambuco, Brazil
  • 2Department of Oceanography, Federal University of Pernambuco, Brazil
  • 3Department of Electrical Engineering and Computers, National University of the South, Argentina
  • 4Department of Statistics and Informatics, Federal Rural University of Pernambuco, Brazil
  • 5Department of Nuclear Energy, Federal University of Pernambuco, Brazil
  • 6School of Environmental Sciences, University of Guelph, Canada
  • 7Department of Fisheries and Aquaculture, Federal Rural University of Pernambuco, Brazil
  • 8Academic Unit of Serra Talhada, Federal Rural University of Pernambuco, Brazil

In this paper, we aim to provide optimal parameters for micro-computed tomography scans of fish otoliths. We tested fifteen different combinations to sagittae. The images were scaled to Hounsfield units, and segmented in two distinct volumes-of-interest (external and internal). The strategy we applied, for identifying optimum scan settings for otoliths, included analyses of the sinogram, the distribution of the Hounsfield units and the signal-to-noise ratio. Based on these tests, the optimum sets of parameters for the acquisition of tomographic images of sagittal otoilths were 80 kV, 220 microA and 0.5 mm aluminum filter.The method allowed 3D shape analysis, internal and external density distribution, layer-by-layer density segmentation, and a potential objective method to count growth rings in otoliths. It was possible to compare mean densities between species, and we observed a significant difference among them. In addition, there are ontogenic changes, which could be increasing or decreasing the density. In this study, we applied tomography for several otolith analysis, that could be of great interest for future studies in diverse areas that use otoliths as the basic structure of analysis, or represents a new research line called eco-densitometry of otoliths, where tomography could be applied to explore the density within an ecological perspective.

Keywords: Eco-densitometry, fishery biology, Hounsfield Units (HU), Radiodensity, MeshLab, 3D otoliths

Received: 16 Aug 2019; Accepted: 08 Nov 2019.

Copyright: © 2019 Vasconcelos-Filho, Thomsen, Stosic, Antonino, Duarte, Heck, Lessa, Santana, Ferreira and Duarte-Neto. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Paulo J. Duarte-Neto, Federal Rural University of Pernambuco, Recife, Brazil, pjduarteneto@gmail.com