MEPS 575:137-152 (2017)  -  DOI:

Using otolith organic matter to detect diet shifts in Bardiella chrysoura, during a period of environmental changes

C. Sirot1,*, P. Grønkjær2, J. Brøgger Pedersen2, J. Panfili1, M. Zetina-Rejon3, A. Tripp-Valdez3, J. Ramos-Miranda4, D. Flores-Hernandez4, A. Sosa-Lopez4, A. M. Darnaude1

1Center for Marine Biodiversity, Exploitation & Conservation, UMR MARBEC, Bat. 24 - CC093, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
2Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
3Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN), Politécnico Nacional, El Conchalito, 23096 La Paz, Baja California Sur, Mexico
4Centro de Ecologia, Pesqueria y Oceanografia de Golfo de Mexico (EPOMEX), Universidad Autonoma de Campeche, 24030 Campeche, Mexico
*Corresponding author:

ABSTRACT: Accurate knowledge on fish trophic ecology and its modifications is crucial for understanding the impact of global change on ecosystems. In this context, we investigated the value of the δ13C and δ15N of otolith soluble organic matter (SOM) for identifying temporal diet shifts in American silver perch Bairdiella chrysoura over a 30-yr period characterized by strong changes in its population size and habitats within the Terminos Lagoon (Mexico). We first compared the otolith SOM isotopic signatures from present-day adults to those of muscle and the main local prey. Our results suggest that otolith SOM can be confidently extracted and analyzed for both present and past otoliths of this species. The mean otolith SOM signatures obtained (-15.92 ± 1.35‰ for δ13C and 9.38 ± 0.93‰ for δ15N) were consistent with those of the diet as 85% of the individual signatures were included within the prey isotopic niche area. Moreover, this study supports a trophic enrichment factor between diet and otolith (TEFdiet-otolith) close to 0 for δ15N, while for δ13C, the TEFotolith-muscle of +0.02‰ warrants further investigation. Then, we compared past and contemporary otolith SOM signatures to investigate temporal diet shifts in B. chrysoura. This showed that δ13C and δ15N differed significantly between the past and present period even if the temporal shift remained relatively small (respectively +1.17‰ and –0.55‰). The present study substantiates the use of otolith SOM δ13C and δ15N as a proxy of fish present and past trophic position, opening the possibility for major progress in studies of temporal changes in food web ecology.

KEY WORDS: Trophic ecology · Stable isotope analysis · Coastal ecosystem · Bairdiella chrysoura · Terminos Lagoon

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Cite this article as: Sirot C, Grønkjær P, Pedersen JB, Panfili J and others (2017) Using otolith organic matter to detect diet shifts in Bardiella chrysoura, during a period of environmental changes. Mar Ecol Prog Ser 575:137-152.

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