El Niño – Southern Oscillation drives variations in growth and otolith chemistry in a top predatory fish
Sclerochronological approaches using fish otoliths provide a powerful and cost-effective means to evaluate fish responses to environmental variations in regions where there is a paucity of long-term data. We hypothesised that the dynamism in the environmental conditions associated with El Niño South...
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| Autores principales: | , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Elsevier
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/9ce7020727bb434db628311392668f66 |
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| Sumario: | Sclerochronological approaches using fish otoliths provide a powerful and cost-effective means to evaluate fish responses to environmental variations in regions where there is a paucity of long-term data. We hypothesised that the dynamism in the environmental conditions associated with El Niño Southern Oscillation (ENSO) events in the Southern Atlantic Ocean would likely influence growth patterns and chemical records in fish otoliths. Hence, we developed a 46-year otolith increment-based growth chronology, and otolith chemical chronologies of Sr:Ca and Ba:Ca for an iconic top predatory fish, the dusky grouper Epinephelus marginatus collected off the southern coast of Brazil. Using a set of increasingly complex mixed-effects linear models, our biochronological approach revealed the influence of intrinsic and large-scale environmental drivers on growth and otolith chemical composition of dusky grouper. In particular, the intensity of the Multivariate ENSO index (a measure of the status of ENSO and El Niño or La Niña conditions) was negatively associated with growth, with rapid drops in average growth evident in very strong El Niño events (1992–93, 1997–98, or 2015–16). Similar negative relationships between ENSO and Ba:Ca composition reflected variations in environmental histories of dusky groupers, a species that is mostly sedentary in coastal reefs, whilst no environmental effects were detected for Sr:Ca. Overall, identifying the drivers that underlie variations in fish growth is a crucial challenge for any conservation or fisheries interest species as population dynamics, persistence and sustainable harvesting are tightly linked to individual growth. The development of chemical chronologies provided insight towards relating otolith elemental variation to environmental conditions at multidecadal scales, encouraging further evaluations of individual and population-level fluctuations of otolith chemistry and environmental reconstructions. |
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