Age and growth assessment of the near-threatened fish Rita rita (Siluriformes: Bagridae) in the Ganges basin
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| Autores: | , , |
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| Formato: | artículo original |
| Estado: | Versión publicada |
| Fecha de Publicación: | 2023 |
| Descripción: | Introduction: Rita rita is a freshwater catfish, facing threats of extinction mainly due to the loss of breeding and nursing grounds. To provide useful information to fisheries managers, the selection of the most suitable ageing structure for age and growth estimation is very crucial. Objective: To identify the best structure determining precise age estimate and to study growth in Rita rita. Methods: Ageing precision in the fish was assessed based on Average Percent Error (APE), Coefficient Variation (CV), and Percent Agreement (PA) between readers as well as between structures. A total of 390 fish samples were collected from the three rivers: Ganga, Yamuna and Ramganga from September 2018 to August 2019. The annulus formation was validated using MIA, and the VBGF equation was developed using length-at-age data from the structure giving a precise age estimate. Results: Vertebrae provided a precise age estimate in Rita rita as evidenced by the least average percentage of error (APE) and coefficient of variation (CV) values, and the highest percent agreement (PA) value. The Marginal Increment Analysis on vertebrae suggested that the growth band was annual and formed from May to September. The growth equations for the fish in the selected rivers were Lt = 90.19(1-e-0.145(t+0.51)) for River Ganga; Lt = 91.19 (1-e-0.14(t+0.59)) for River Yamuna and Lt = 89.63 (1-e-0.15(t+0.68)) for River Ramganga. Conclusion: The vertebrae may be used for precise age estimation in Rita rita VBGF equations showed moderate fish growth in all the rivers. In case of the non-availability of vertebrae for age estimation, we may prefer to use sectioned otoliths followed by whole otoliths and opercular bones. The use of pectoral spines should be avoided for age estimation, especially in older fish specimens. |
| País: | Portal de Revistas UCR |
| Institución: | Universidad de Costa Rica |
| Repositorio: | Portal de Revistas UCR |
| Lenguaje: | Inglés |
| OAI Identifier: | oai:portal.revistas.ucr.ac.cr:article/11369 |
| Acceso en línea: | https://revistas.ucr.ac.cr/index.php/rrbt/article/view/11369 |
| Palabra clave: | vertebrae otoliths ageing precision VBGF Marginal Increment Analysis vértebras otolitos precisión de la edad Análisis del Incremento Marginal |