Fully-automated identification of fish species based on otolith contour: using short-time Fourier transform and discriminant analysis (STFT-DA)

Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia
Institute of Ocean & Earth Sciences, University of Malaya, Kuala Lumpur, Malaysia
DOI
10.7287/peerj.preprints.1517v1
Subject Areas
Aquaculture, Fisheries and Fish Science, Bioinformatics, Marine Biology, Taxonomy, Computational Science
Keywords
Automated taxon identification, Otolith shape analysis, Short-time Fourier transform, Discriminant analysis
Copyright
© 2015 Salimi et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Salimi N, Loh KH, Kaur Dhillon S, Chong VC. 2015. Fully-automated identification of fish species based on otolith contour: using short-time Fourier transform and discriminant analysis (STFT-DA) PeerJ PrePrints 3:e1517v1

Abstract

Background. Fish species may be identified based on their unique otolith shape or contour. Several pattern recognition methods have been proposed to classify fish species through morphological features of the otolith contours. However, there has been no fully-automated species identification model with the accuracy higher than 80%. The purpose of the current study is to develop a fully-automated model, based on the otolith contours, to identify the fish species with the high classification accuracy. Methods. Images of the right sagittal otoliths of 14 fish species from three families namely Sciaenidae, Ariidae, and Engraulidae were used to develop the proposed identification model. Short-time Fourier transform (STFT) was used, for the first time in the area of otolith shape analysis, to extract important features of the otolith contours. Discriminant Analysis (DA), as a classification technique, was used to train and test the model based on the extracted features. Results. Performance of the model was demonstrated using species from three families separately, as well as all species combined. Overall classification accuracy of the model was greater than 90% for all cases. In addition, effects of STFT variables on the performance of the identification model were explored in this study. Conclusions. Short-time Fourier transform could determine important features of the otolith outlines. The fully-automated model proposed in this study (STFT-DA) could predict species of an unknown specimen with acceptable identification accuracy. The current model has flexibility to be used for more species and families in future studies.

Author Comment

This article is currently being peer-reviewed in the journal PeerJ.

Supplemental Information

MATLAB scripts and function used for training and testing the model

DOI: 10.7287/peerj.preprints.1517v1/supp-1

otolith images of Arius maculatus species (Ariidae family) used to train and test the model

DOI: 10.7287/peerj.preprints.1517v1/supp-2

otolith images of Cryptarius truncatus species from Ariidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-3

otolith images of Hexanematichtys sagor species from Ariidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-4

otolith images of Nemapteryx caelata species from Ariidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-5

otolith images of Osteogeneiosus militaris species from Ariidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-6

otolith images of Plicofollis argyropleuron species from Ariidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-7

otolith images of Coilia dussumieri species from Engraulidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-8

otolith images of Setipinna taty species from Engraulidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-9

otolith images of Thryssa hamiltonii species from Engraulidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-10

otolith images of Dendrophysa russelli species from Sciaenidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-11

otolith images of Johnius belangerii species from Sciaenidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-12

otolith images of Johnius carouna species from Sciaenidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-13

otolith images of Otolithes ruber species from Sciaenidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-14

otolith images of Panna microdon species from Sciaenidae family

DOI: 10.7287/peerj.preprints.1517v1/supp-15