Otolith shape as a stock discrimination tool for ling (Genypterus blacodes) in the fjords of Chilean Patagonia |
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| Authors: | Rodrigo Wiff Andrés Flores Angel M Segura Mauricio A Barrientos Vilma Ojeda |
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| Institution: | 1. Center of Applied Ecology and Sustainability (CAPES-UC), Departamento de Ecología, Pontificia Universidad Católica de Chile, Santiago, Chile rodrigo.wiff@gmail.com;3. Escuela de Ciencias del Mar, Facultad de Ciencias del Mar y Geografía, Pontificia Universidad Católica de Valparaíso (PUCV), Valparaíso, Chile;4. Modelización y análisis de recursos naturales (MAREN), CURE, Universidad de la Republica, Rocha, Uruguay;5. Instituto de Matemáticas, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile;6. División de Investigación pesquera, Instituto de Fomento Pesquero (IFOP), Valparaíso, Chile |
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| Abstract: | ABSTRACT Genypterus blacodes, in terms of its fishing history and local economic importance, is an emblematic species harvested in Chilean Patagonia (41°00’–57°00’S). Most of the current fisheries and biological knowledge of this species come from the open ocean, whereas information about the species in fjords and inner channels is fragmentary. In 2018, two research surveys targeting G. blacodes were conducted in the fjords and inner channels of Chilean Patagonia. A total of 253 pairs of sagittal otoliths were sampled at three different localities, and their contours were modelled using wavelet analysis as a tool for stock discrimination. Contours were compared using canonical analysis, and classification was performed using linear discriminant and Random Forest analyses. The results indicated that the wavelet method is efficient in modelling otolith contours, and the discriminant analyses showed differences among fishing grounds across the latitudinal gradient, thus confirming the hypothesis that G. blacodes conform to at least two separate stock units in Chilean Patagonia. Fishing grounds that were closer in space showed higher levels of misclassification. The discussion focuses on how environmental variables and the geography of fjords shape stock differences and how this information can be used for the sustainable management of G. blacodes. |
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| Keywords: | Wavelet transform Patagonia ling morphometry sagittal otolith |
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