Blue whiting otoliths pair’s symmetry side effect

Otoliths are paired calcified structures located in the inner ear of the teleost fishes. Fisheries scientists have been using the otoliths for a variety of applications as fish ageing, species identification and also species interaction. The symmetry between left and right otoliths is considered species dependent. The application of analysis techniques on otoliths images has been increasing in recent years. The diagnosis on otoliths symmetry as a species characteristic is currently being done. It is expected that the otolith surface (distal versus proximal) used to collect images should have no influence on the symmetry results. The goal of this study is to investigate if the otolith position (distal versus proximal) when analyse images has influence in the diagnostic of the symmetry shape between the left and right otoliths. The results showed that the otolith face orientation should be taken into account during the otoliths images processing for symmetry shape analysis. On blue whiting the otolith images should always be obtained from the concave side, because for symmetry studies the position real matter