INVESTIGADORES
THOMPSON Gustavo Ariel
congresos y reuniones científicas
Título:
Otolith perimeter as a tool in the identification of coexisting species of silversides in Argentina.
Autor/es:
MORAWICK, SANTIAGO; SOLIMANO, PATRICIO; THOMPSON, GUSTAVO; VOLPEDO, ALEJANDRA
Lugar:
Valparaiso
Reunión:
Simposio; 7th International Otolith Symposium; 2023
Institución organizadora:
Pontifica Universidad Catolica de Valparaiso
Resumen:
Argentina has one of the largest numbers of species of the genus Odontesthes that coexist in the world (Odontesthes argentinensis, O. platensis, O. smitti, O. nigricans, O. incisa, O. bonariensis and O. hatcheri). These species have an important ecological role in the trophic webs in the region. However, due to the number of species of the genus Odontesthes, many times the identification of otoliths in feces and stomach contents of ichthyophages is complex. The objective of this paper is to use otolith perimeter as a morphometric tool for the identification of seven species of silversides that coexist in marine and freshwater environments of Argentina. The sagittae otoliths were extracted from a total of 369 silversides, which were photographed under a stereoscopic magnifying glass and the images were processed using the ShapeR package of the R statistical software. The Wavelet coefficients (CW) and Fourier descriptors (DF) obtained were analyzed using multivariate methods. The results show that with CW the percentage of correctly classified silversides was 71.27%, while with DF it was 81.75% and using CW and DR together, 88.35% was obtained. The PERMANOVA analysis revealed that there are significant differences (p<0.0001) between the otolith perimeter of these species. The otoliths of O. platensis, O. argentinensis, O. smitti and O. bonariensis have elongated shapes, while those of O. nigricans and O. incisa are rounded. The greatest variations in shape are observed in the antero-posterior axis of the otolith (rostrum and antirostrum) and at the posterior end. The results found contribute to the identification of these species of silversides in dietary studies of trophic ecology of ichthyophages in the region.