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4. Mercury Stable Isotopes Reveal the Vertical Distribution and Trophic Ecology of Deep-Pelagic Organisms over the North-East Atlantic Ocean Continental Slope

Author

Médieu, Anaïs, Spitz, Jérôme, Point, David, Sonke, Jeroen E., Loutrage, Liz, Laffont, Laure, and Chouvelon, Tiphaine

Abstract

Deep-pelagic species are central to marine ecosystems and increasingly vulnerable to global change and human exploitation. To date, our understanding of these communities remains limited mainly due to the difficulty of observations, calling for complementary innovative tools to better characterize their ecology. We used mercury (Δ199Hg, δ202Hg, Δ201Hg, and Δ200Hg), carbon (δ13C), and nitrogen (δ15N) stable isotope compositions to segregate deep-pelagic species caught on the continental slope of the Bay of Biscay (NE Atlantic) according to their foraging depth and trophic ecology. Decreasing fish Δ199Hg values with corresponding depth estimates from the surface to down to 1,800 m confirmed that mercury isotopes are able to segregate deep species over a large vertical gradient according to their foraging depth. Results from isotopic compositions also identified different mercury sources, likely reflecting different trophic assemblages over the continental slope, in particular, the demersal influence for some species, compared to purely oceanic species. Overall, our results demonstrate how mercury stable isotopes can inform the vertical foraging habitat of little-known species and communities feeding in the deep.

Published
2024
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6. Stable Tuna Mercury Concentrations since 1971 Illustrate Marine Inertia and the Need for Strong Emission Reductions under the Minamata Convention

Author

Médieu, Anaïs, primary, Point, David, additional, Sonke, Jeroen E., additional, Angot, Hélène, additional, Allain, Valérie, additional, Bodin, Nathalie, additional, Adams, Douglas H., additional, Bignert, Anders, additional, Streets, David G., additional, Buchanan, Pearse B., additional, Heimbürger-Boavida, Lars-Eric, additional, Pethybridge, Heidi, additional, Gillikin, David P., additional, Ménard, Frédéric, additional, Choy, C. Anela, additional, Itai, Takaaki, additional, Bustamante, Paco, additional, Dhurmeea, Zahirah, additional, Ferriss, Bridget E., additional, Bourlès, Bernard, additional, Habasque, Jérémie, additional, Verheyden, Anouk, additional, Munaron, Jean-Marie, additional, Laffont, Laure, additional, Gauthier, Olivier, additional, and Lorrain, Anne, additional

Published
2024
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7. Otolith chemical fingerprints of skipjack tuna (Katsuwonus pelamis) in the Indian Ocean: First insights into stock structure delineation.

Author

Iraide Artetxe-Arrate, Igaratza Fraile, Jessica Farley, Audrey M Darnaude, Naomi Clear, Naiara Rodríguez-Ezpeleta, David L Dettman, Christophe Pécheyran, Iñigo Krug, Anaïs Médieu, Mohamed Ahusan, Craig Proctor, Asep Priatna, Pratiwi Lestari, Campbell Davies, Francis Marsac, and Hilario Murua

Subjects
Medicine, Science
Abstract

The chemical composition of otoliths (earbones) can provide valuable information about stock structure and connectivity patterns among marine fish. For that, chemical signatures must be sufficiently distinct to allow accurate classification of an unknown fish to their area of origin. Here we have examined the suitability of otolith microchemistry as a tool to better understand the spatial dynamics of skipjack tuna (Katsuwonus pelamis), a highly valuable commercial species for which uncertainties remain regarding its stock structure in the Indian Ocean. For this aim, we have compared the early life otolith chemical composition of young-of-the-year (

Published
2021
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8. Stable mercury concentrations in tunas from the global ocean arise question about monitoring the effectiveness of the Minamata Convention

Author

Médieu, Anaïs, primary, Point, David, additional, Sonke, Jeroen, additional, Buchanan, Pearse, additional, Bodin, Nathalie, additional, Adams, Douglas, additional, Bignert, Anders, additional, Streets, David, additional, Hélène, Angot, additional, Ménard, Frédéric, additional, Choy, C. Anela, additional, Allain, Valérie, additional, Itai, Takaaki, additional, Bustamante, Paco, additional, Ferriss, Bridget, additional, Bourlès, Bernard, additional, Habasque, Jérémie, additional, Gauthier, Olivier, additional, and Lorrain, Anne, additional

Published
2023
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9. Evidence that Pacific tuna mercury levels are driven by marine methylmercury production and anthropogenic inputs

Author

Médieu, Anais, Point, David, Itai, Takaaki, Angot, Hélène, Buchanan, Pearse J., Allain, Valerie, Fuller, Leanne, Griffiths, Shane, Gillikin, David P., Sonke, Jeroen E., Heimbürger-boavida, Lars-eric, Desgranges, Marie-maëlle, Menkes, Christophe E., Madigan, Daniel J., Brosset, Pablo, Gauthier, Olivier, Tagliabue, Alessandro, Bopp, Laurent, Verheyden, Anouk, Lorrain, Anne, Médieu, Anais, Point, David, Itai, Takaaki, Angot, Hélène, Buchanan, Pearse J., Allain, Valerie, Fuller, Leanne, Griffiths, Shane, Gillikin, David P., Sonke, Jeroen E., Heimbürger-boavida, Lars-eric, Desgranges, Marie-maëlle, Menkes, Christophe E., Madigan, Daniel J., Brosset, Pablo, Gauthier, Olivier, Tagliabue, Alessandro, Bopp, Laurent, Verheyden, Anouk, and Lorrain, Anne

Abstract

Pacific Ocean tuna is among the most-consumed seafood products but contains relatively high levels of the neurotoxin methylmercury. Limited observations suggest tuna mercury levels vary in space and time, yet the drivers are not well understood. Here, we map mercury concentrations in skipjack tuna across the Pacific Ocean and build generalized additive models to quantify the anthropogenic, ecological, and biogeochemical drivers. Skipjack mercury levels display a fivefold spatial gradient, with maximum concentrations in the northwest near Asia, intermediate values in the east, and the lowest levels in the west, southwest, and central Pacific. Large spatial differences can be explained by the depth of the seawater methylmercury peak near low-oxygen zones, leading to enhanced tuna mercury concentrations in regions where oxygen depletion is shallow. Despite this natural biogeochemical control, the mercury hotspot in tuna caught near Asia is explained by elevated atmospheric mercury concentrations and/or mercury river inputs to the coastal shelf. While we cannot ignore the legacy mercury contribution from other regions to the Pacific Ocean (e.g., North America and Europe), our results suggest that recent anthropogenic mercury release, which is currently largest in Asia, contributes directly to present-day human mercury exposure.

Published
2022
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10. Investigating natal origins and trans-oceanic migrations in albacore tuna (Thunnus alalunga) from the southwest Indian Ocean using otolith chemistry

Author

Labonne, Maylis, Darnaude, Audrey M, Fily, Theotime, Petit, Cécile, Médieu, Anais, Pernak, Marianne, Nikolic, Natacha, Clear, Naomi, Farley, Jessica, Eveson, Paige, Davies, Campbell, Marsac, Francis, Labonne, Maylis, Darnaude, Audrey M, Fily, Theotime, Petit, Cécile, Médieu, Anais, Pernak, Marianne, Nikolic, Natacha, Clear, Naomi, Farley, Jessica, Eveson, Paige, Davies, Campbell, and Marsac, Francis

Abstract

Variation in otolith elemental fingerprints was investigated in albacore tunas (Thunnus alalunga) sampled in the southwest Indian Ocean (SWI) and along the Atlantic coast of South Africa (SA). A total of 72 otoliths were selected, from 46 adult fish captured around the Reunion Island (SWI) and 26 juvenile and sub-adults sampled at two locations off the South African coast (SA-N and SA-S, n = 13 per location). LA-ICP-MS was used to assess the signatures in 15 chemical elements at all otolith cores (to investigate potential differences in fish spawning origin among regions) and along all otolith edges (to characterize the chemical signatures of fish capture areas). Among the 15 chemical elements analysed, only Mg, P, Zn, Sr, Ba, B and Cu were above detection limits and significantly contributed to the variation in otolith composition. Based on differences in these elements, two groups of distinct multi-elemental signatures, denoting potentially discrete spawning origins (SpO), were identified at the otolith cores using hierarchical clustering based on Euclidian distances. Each of the two potential SpO contributed to the tuna sampled in all three areas, suggesting a common origin in some fish caught in the Atlantic and in the Indian Ocean and important trans-oceanic migrations between these two Oceans. The possible location of the two spawning areas is discussed based on the signatures recorded on the otolith edges before the final capture of the fish, in both oceans. This study was part of a collaborative project on the population structure of tuna, billfish and sharks of the Indian Ocean (PSTBS-IO).

Published
2022

11. Mercury concentrations in tuna blood and muscle mirror seawater methylmercury in the Western and Central Pacific Ocean

Author

Barbosa, Romina, Point, David, Médieu, Anais, Allain, Valerie, Gillikin, David P., Couturier, Lydie I.e., Munaron, Jean-marie, Roupsard, François, Lorrain, Anne, Barbosa, Romina, Point, David, Médieu, Anais, Allain, Valerie, Gillikin, David P., Couturier, Lydie I.e., Munaron, Jean-marie, Roupsard, François, and Lorrain, Anne

Abstract

Understanding the relationship between mercury in seafood and the distribution of oceanic methylmercury is key to understand human mercury exposure. Here, we determined mercury concentrations in muscle and blood of bigeye and yellowfin tunas from the Western and Central Pacific. Results showed similar latitudinal patterns in tuna blood and muscle, indicating that both tissues are good candidates for mercury monitoring. Complementary tuna species analyses indicated species- and tissue- specific mercury patterns, highlighting differences in physiologic processes of mercury uptake and accumulation associated with tuna vertical habitat. Tuna mercury content was correlated to ambient seawater methylmercury concentrations, with blood being enriched at a higher rate than muscle with increasing habitat depth. The consideration of a significant uptake of dissolved methylmercury from seawater in tuna, in addition to assimilation from food, might be interesting to test in models to represent the spatiotemporal evolutions of mercury in tuna under different mercury emission scenarios.

Published
2022
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12. Evidence that Pacific tuna mercury levels are driven by marine methylmercury production and anthropogenic inputs

Author

Anaïs Médieu, David Point, Takaaki Itai, Hélène Angot, Pearse J. Buchanan, Valérie Allain, Leanne Fuller, Shane Griffiths, David P. Gillikin, Jeroen E. Sonke, Lars-Eric Heimbürger-Boavida, Marie-Maëlle Desgranges, Christophe E. Menkes, Daniel J. Madigan, Pablo Brosset, Olivier Gauthier, Alessandro Tagliabue, Laurent Bopp, Anouk Verheyden, Anne Lorrain, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Department of Earth and Planetary Science [Tokyo], Graduate School of Science [Tokyo], The University of Tokyo (UTokyo)-The University of Tokyo (UTokyo), Extreme Environments Research Laboratory (EERL), Ecole Polytechnique Fédérale de Lausanne (EPFL), Department of Earth Ocean and Ecological Sciences [Liverpool], University of Liverpool, Communauté du Pacifique/Pacific Community, Inter-American Tropical Tuna Commission (IATTC), Union College, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), University of Windsor [Ca], Dynamique et durabilité des écosystèmes : de la source à l’océan (DECOD), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de Recherche pour le Développement (IRD), ANR-17-CE34-0010 MERTOX, ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), ANR-17-CE34-0010,MERTOX,Découvrir l'origine de la toxine methylmercure dans les écosystèmes marins(2017), Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Oceanic Fisheries Programme, INSU Division Technique de l'INSU [Site de Brest], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Windsor, Windsor, ON, N9B 3P4, Canada, Université de Brest (UBO), and PacificFundVACOPA Project (spatial VAriations of COntaminants levels in PAcificoceantrophic webs)

Subjects
Geologic Sediments, Asia, Food Chain, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], [SDE.MCG]Environmental Sciences/Global Changes, skipjack tuna, 010501 environmental sciences, 01 natural sciences, Sustainability Science, Methylation, atmospheric inputs, spatial modeling, biogeochemistry, Animals, Humans, Seawater, Water Pollutants, 14. Life underwater, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, Pacific Ocean, Ecology, Tuna, food and beverages, methylmercury, Methylmercury, Mercury, Biological Sciences, Methylmercury Compounds, Models, Theoretical, Europe, Seafood, 13. Climate action, North America, [SDE]Environmental Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, human activities, Environmental Sciences, Water Pollutants, Chemical, Environmental Monitoring
Abstract

Significance Humans are exposed to toxic methylmercury mainly by consuming marine fish. New environmental policies under the Minamata Convention rely on a yet-poorly-known understanding of how mercury emissions translate into fish methylmercury levels. Here, we provide the first detailed map of mercury concentrations from skipjack tuna across the Pacific. Our study shows that the natural functioning of the global ocean has an important influence on tuna mercury concentrations, specifically in relation to the depth at which methylmercury concentrations peak in the water column. However, mercury inputs originating from anthropogenic sources are also detectable, leading to enhanced tuna mercury levels in the northwestern Pacific Ocean that cannot be explained solely by oceanic processes., Pacific Ocean tuna is among the most-consumed seafood products but contains relatively high levels of the neurotoxin methylmercury. Limited observations suggest tuna mercury levels vary in space and time, yet the drivers are not well understood. Here, we map mercury concentrations in skipjack tuna across the Pacific Ocean and build generalized additive models to quantify the anthropogenic, ecological, and biogeochemical drivers. Skipjack mercury levels display a fivefold spatial gradient, with maximum concentrations in the northwest near Asia, intermediate values in the east, and the lowest levels in the west, southwest, and central Pacific. Large spatial differences can be explained by the depth of the seawater methylmercury peak near low-oxygen zones, leading to enhanced tuna mercury concentrations in regions where oxygen depletion is shallow. Despite this natural biogeochemical control, the mercury hotspot in tuna caught near Asia is explained by elevated atmospheric mercury concentrations and/or mercury river inputs to the coastal shelf. While we cannot ignore the legacy mercury contribution from other regions to the Pacific Ocean (e.g., North America and Europe), our results suggest that recent anthropogenic mercury release, which is currently largest in Asia, contributes directly to present-day human mercury exposure.

Published
2022
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13. Evidence that Pacific tuna mercury levels are driven by marine methylmercury production and anthropogenic inputs

Author

Médieu, Anaïs, primary, Point, David, additional, Itai, Takaaki, additional, Angot, Hélène, additional, Buchanan, Pearse J., additional, Allain, Valérie, additional, Fuller, Leanne, additional, Griffiths, Shane, additional, Gillikin, David P., additional, Sonke, Jeroen E., additional, Heimbürger-Boavida, Lars-Eric, additional, Desgranges, Marie-Maëlle, additional, Menkes, Christophe E., additional, Madigan, Daniel J., additional, Brosset, Pablo, additional, Gauthier, Olivier, additional, Tagliabue, Alessandro, additional, Bopp, Laurent, additional, Verheyden, Anouk, additional, and Lorrain, Anne, additional

Published
2022
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14. ENSO Climate Forcing of the Marine Mercury Cycle in the Peruvian Upwelling Zone Does Not Affect Methylmercury Levels of Marine Avian Top Predators

Author

Dimitri Gutiérrez, François Colas, Arnaud Bertrand, Amédée Roy, David Point, Anne Lorrain, Sophie Bertrand, Jeroen E. Sonke, Michelle Graco, J.M. Munaron, Anaïs Médieu, Daniel Grados, Marina Renedo, Alice Pietri, Yann Tremblay, Hervé Demarcq, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Universidad Peruana Cayetano Heredia (UPCH), Instituto del Mar del Peru (IMARPE), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), ANR-17-CE34-0010,MERTOX,Découvrir l'origine de la toxine methylmercure dans les écosystèmes marins(2017), and ANR-09-JCJC-0026,TOPINEME,Les prédateurs supérieurs comme indicateurs des dynamiques de l'écosystème marin exploité(2009)

Subjects
010504 meteorology & atmospheric sciences, Effects of global warming on oceans, [SDE.MCG]Environmental Sciences/Global Changes, Climate change, 010501 environmental sciences, Oxygen minimum zone, 01 natural sciences, Birds, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Peru, Environmental Chemistry, Animals, 14. Life underwater, Mercury cycle, 0105 earth and related environmental sciences, El Nino-Southern Oscillation, MIF, Biogeochemistry, General Chemistry, Mercury, Methylmercury Compounds, La Niña, Sea surface temperature, Oceanography, Hg stable isotopes, climate change, 13. Climate action, Upwelling, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ecology, Northern Humboldt current system, Water Pollutants, Chemical, Environmental Monitoring
Abstract

Publisher: American Chemical Society; International audience; Climate change is expected to affect marine mercury (Hg) biogeochemistry and biomagnification. Recent modeling work suggested that ocean warming increases methylmercury (MeHg) levels in fish. Here, we studied the influence of El Niño Southern Oscillations (ENSO) on Hg concentrations and stable isotopes in time series of seabird blood from the Peruvian upwelling and oxygen minimum zone. Between 2009 and 2016, La Niña (2011) and El Niño conditions (2015–2016) were accompanied by sea surface temperature anomalies up to 3 °C, oxycline depth change (20–100 m), and strong primary production gradients. Seabird Hg levels were stable and did not co-vary significantly with oceanographic parameters, nor with anchovy biomass, the primary dietary source to seabirds (90%). In contrast, seabird Δ$^{199}$Hg, proxy for marine photochemical MeHg breakdown, and δ$^{15}$N showed strong interannual variability (up to 0.8 and 3‰, respectively) and sharply decreased during El Niño. We suggest that lower Δ$^{199}$Hg during El Niño represents reduced MeHg photodegradation due to the deepening of the oxycline. This process was balanced by equally reduced Hg methylation due to reduced productivity, carbon export, and remineralization. The non-dependence of seabird MeHg levels on strong ENSO variability suggests that marine predator MeHg levels may not be as sensitive to climate change as is currently thought.

Published
2021
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16. Lipid-free tuna muscle samples are suitable for total mercury analysis

Author

Fany Sardenne, Hervé Le Delliou, Chloé Pazart, Anne Lorrain, David Point, Nathalie Bodin, and Anaïs Médieu

Subjects
0106 biological sciences, chemistry.chemical_element, Aquatic Science, Oceanography, 010603 evolutionary biology, 01 natural sciences, chemistry.chemical_compound, Animals, Humans, Yellowfin, Fat content, Methylmercury, Skipjack, Delipidation, δ13C, Tuna, 010604 marine biology & hydrobiology, Flesh, Muscles, food and beverages, General Medicine, δ15N, Mercury, Methylmercury Compounds, Pollution, Lipids, Mercury (element), chemistry, Bioaccumulation, Environmental chemistry, Bigeye, human activities
Abstract

Tropical tunas are largely consumed worldwide, providing major nutritional benefits to humans, but also representing the main exposure to methylmercury, a potent neurotoxin that biomagnifies along food webs. The combination of ecological tracers (nitrogen and carbon stable isotopes, δ15N and δ13C) to mercury concentrations in tunas is scarce yet crucial to better characterize the influence of tuna foraging ecology on mercury exposure and bioaccumulation. Given the difficulties to get modern and historical tuna samples, analyses have to be done on available and unique samples. However, δ13C values are often analysed on lipid-free samples to avoid bias related to lipid content. While lipid extraction with non-polar solvents is known to have no effect on δ15N values, its impact on mercury concentrations is still unclear. We used white muscle tissues of three tropical tuna species to evaluate the efficiency and repeatability of different lipid extraction protocols commonly used in δ13C and δ15N analysis. Dichloromethane was more efficient than cyclohexane in extracting lipids in tuna muscle, while the automated method appeared more efficient but as repeatable as the manual method. Lipid extraction with dichloromethane had no effect on mercury concentrations. This may result from i) the affinity of methylmercury to proteins in tuna flesh, ii) the low lipid content in tropical tuna muscle samples, and iii) the non-polar nature of dichloromethane. Our study suggests that lipid-free samples, usually prepared for tropical tuna foraging ecology research, can be used equivalently to bulk samples to document in parallel mercury concentrations at a global scale.

Published
2021

17. ENSO Climate Forcing of the Marine Mercury Cycle in the Peruvian Upwelling Zone Does Not Affect Methylmercury Levels of Marine Avian Top Predators

Author

Renedo, Marina, primary, Point, David, additional, Sonke, Jeroen E., additional, Lorrain, Anne, additional, Demarcq, Hervé, additional, Graco, Michelle, additional, Grados, Daniel, additional, Gutiérrez, Dimitri, additional, Médieu, Anaïs, additional, Munaron, Jean Marie, additional, Pietri, Alice, additional, Colas, François, additional, Tremblay, Yann, additional, Roy, Amédée, additional, Bertrand, Arnaud, additional, and Bertrand, Sophie Lanco, additional

Published
2021
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18. Mercury concentrations in tuna blood and muscle mirror seawater methylmercury in the Western and Central Pacific Ocean

Author

Romina V. Barbosa, David Point, Anaïs Médieu, Valérie Allain, David P. Gillikin, Lydie I.E. Couturier, Jean-Marie Munaron, François Roupsard, Anne Lorrain, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Pacific community (SPC), and ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)

Subjects
Pacific Ocean, Tuna, Muscles, Methylmercury, Mercury, Methylmercury Compounds, Aquatic Science, Oceanography, Pollution, White muscle, Tunas, Blood, Vertical habitat, [SDE]Environmental Sciences, Animals, Humans, Seawater
Abstract

International audience; Understanding the relationship between mercury in seafood and the distribution of oceanic methylmercury is key to understand human mercury exposure. Here, we determined mercury concentrations in muscle and blood of bigeye and yellowfin tunas from the Western and Central Pacific. Results showed similar latitudinal patterns in tuna blood and muscle, indicating that both tissues are good candidates for mercury monitoring. Complementary tuna species analyses indicated species- and tissue- specific mercury patterns, highlighting differences in physiologic processes of mercury uptake and accumulation associated with tuna vertical habitat. Tuna mercury content was correlated to ambient seawater methylmercury concentrations, with blood being enriched at a higher rate than muscle with increasing habitat depth. The consideration of a significant uptake of dissolved methylmercury from seawater in tuna, in addition to assimilation from food, might be interesting to test in models to represent the spatiotemporal evolutions of mercury in tuna under different mercury emission scenarios.

Published
2022
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19. Otolith chemical fingerprints of skipjack tuna (Katsuwonus pelamis) in the Indian Ocean: First insights into stock structure delineation

Author

Audrey M. Darnaude, Pratiwi Lestari, Campbell R. Davies, David L. Dettman, Jessica H. Farley, Naiara Rodríguez-Ezpeleta, Iraide Artetxe-Arrate, Igaratza Fraile, Naomi P. Clear, Craig Proctor, Anaïs Médieu, Iñigo Krug, Francis Marsac, Asep Priatna, Christophe Pécheyran, Mohamed Ahusan, Hilario Murua, AZTI - Tecnalia, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Skipjack tuna, Composite Particles, Atmospheric Science, Monsoons, 01 natural sciences, Otolith, Analytical Chemistry, Isotopes, Oceans, Medicine and Health Sciences, Marine Fish, Indian Ocean, Skipjack, Climatology, Multidisciplinary, δ13C, biology, Physics, Stable Isotopes, Eukaryota, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Chemistry, Oceanography, medicine.anatomical_structure, Osteichthyes, Inner Ear, Vertebrates, Physical Sciences, Medicine, Anatomy, Research Article, Atoms, δ18O, Fish Biology, Science, Marine Biology, Monsoon, 010603 evolutionary biology, Otolithic Membrane, Bodies of water, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, medicine, Fish Physiology, Animals, Animal Physiology, 14. Life underwater, Particle Physics, Tuna, 010604 marine biology & hydrobiology, Trace element, Organisms, Biology and Life Sciences, biology.organism_classification, Vertebrate Physiology, Trace Elements, Marine and aquatic sciences, Earth sciences, Fish, [CHIM.POLY]Chemical Sciences/Polymers, Ears, Head, Zoology
Abstract

The chemical composition of otoliths (earbones) can provide valuable information about stock structure and connectivity patterns among marine fish. For that, chemical signatures must be sufficiently distinct to allow accurate classification of an unknown fish to their area of origin. Here we have examined the suitability of otolith microchemistry as a tool to better understand the spatial dynamics of skipjack tuna (Katsuwonus pelamis), a highly valuable commercial species for which uncertainties remain regarding its stock structure in the Indian Ocean. For this aim, we have compared the early life otolith chemical composition of young-of-the-year (13C, δ18O) signatures were used, from individuals captured in 2018 and 2019. Otolith Sr:Ca, Ba:Ca, Mg:Ca and δ18O significantly differed among fish from different nurseries, but, in general, the chemical signatures of the three nursery areas largely overlapped. Multivariate analyses of otolith chemical signatures revealed low geographic separation among Central and Eastern nurseries, achieving a maximum overall random forest cross validated classification success of 51%. Cohort effect on otolith trace element signatures was also detected, indicating that variations in chemical signatures associated with seasonal changes in oceanographic conditions must be well understood, particularly for species with several reproductive peaks throughout the year. Otolith microchemistry in conjunction with other techniques (e.g., genetics, particle tracking) should be further investigated to resolve skipjack stock structure, which will ultimately contribute to the sustainable management of this stock in the Indian Ocean.

Published
2021
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20. Investigating natal origin and trans-oceanic migrations of Albacore tuna (Thunnus alalunga) from the West Indian Ocean using otolith chemistry

Author

Labonne, Maylis, Darnaude, Audrey, Petit, Cécile, Médieu, Anais, Pernak, Marianne, Nikolic, Natacha, Clear, Naomi, Eveson, J, Farley, Jessica, Marsac, Francis, Davies, Campbell, and Labonne, Maylis

Subjects
[SDV] Life Sciences [q-bio], [CHIM] Chemical Sciences
Abstract

Natal origin of 92 Albacore tuna (Thunnus alalunga) from the West Indian Ocean was investigated using trace elements in otoliths. Otoliths were collected from (i) 46 juveniles caught in 2 locations in South Africa (SA-North and SA-South) in 2018 and Tasmania (SWTS) in 2019, which are both known to be nurseries areas for the species, and (ii) 46 older fish caught in the Reunion island (SWI) during 3 sampling events in 2018. Otolithsconcentrations in seven chemical elements (B, Mg, P, Cu, Zn, Sr and Ba) were analysed by LA-ICP-MS at two points, near the core and at the edge, providing an elemental signal from the material deposited while the fish were close to their spawning grounds and from material deposited while they were in (or close) to their capture areas, respectively. Core and edge signatures for the same otolith were significantly different for most elements.At the edge, PCA identified different signatures (in Sr, Ba, and B) between the 3 main capture areas. Multi-elemental signatures for the Reunion samples were stable over the 3 sampling events. Those for South Africa samples split into 2 groups, the group of juveniles sampled in the Atlantic (SA- North) exhibiting signatures in B statistically different from those of all the juveniles from the Indian Ocean (SA-South and SWTS).The PCA on core signatures (from West Indian ocean and Atlantic ocean samples) identified some variation in spawning origin according to fish capture location. Based on the most relevant number of clusters, 2 putative spawning origins (SpO) with distinct chemical signatures in B and P were identified. All two SpO apparently contribute to the 3 sampling events investigated, but in varied proportions. Interestingly, although someoverlap was found between SA-North and SA-South signatures, the two juvenile sampling locations mostly had different spawning origin. SpO-2 was identified as the main spawning source for the albacore analysed (52%), principally in SA-S (76%), SWI-May18 (62%) and SWI-Dec18 (70%). SpO-1 apparently provides 47% of the fishsampled, principally in SA-N (69%) and SWI-Feb18 (85%). The samples collected do not allow to prove that these different spawning origins correspond to spatially discrete zones in the Indian or Atlantic Ocean. Nonetheless, these results bring evidence for trans-oceanic migrations in T. alalunga, which has strong implications for the management of its stocks

Published
2021

21. Otolith chemical fingerprints of skipjack tuna (Katsuwonus pelamis) in the Indian Ocean: First insights into stock structure delineation

Author

Artetxe-arrate, Iraide, Fraile, Igaratza, Farley, Jessica, Darnaude, Audrey M., Clear, Naomi, Rodríguez-ezpeleta, Naiara, Dettman, David L., Pécheyran, Christophe, Krug, Iñigo, Médieu, Anais, Ahusan, Mohamed, Proctor, Craig, Priatna, Asep, Lestari, Pratiwi, Davies, Campbell, Marsac, Francis, Murua, Hilario, Artetxe-arrate, Iraide, Fraile, Igaratza, Farley, Jessica, Darnaude, Audrey M., Clear, Naomi, Rodríguez-ezpeleta, Naiara, Dettman, David L., Pécheyran, Christophe, Krug, Iñigo, Médieu, Anais, Ahusan, Mohamed, Proctor, Craig, Priatna, Asep, Lestari, Pratiwi, Davies, Campbell, Marsac, Francis, and Murua, Hilario

Abstract

The chemical composition of otoliths (earbones) can provide valuable information about stock structure and connectivity patterns among marine fish. For that, chemical signatures must be sufficiently distinct to allow accurate classification of an unknown fish to their area of origin. Here we have examined the suitability of otolith microchemistry as a tool to better understand the spatial dynamics of skipjack tuna (Katsuwonus pelamis), a highly valuable commercial species for which uncertainties remain regarding its stock structure in the Indian Ocean. For this aim, we have compared the early life otolith chemical composition of young-of-the-year (<6 months) skipjack tuna captured from the three main nursery areas of the equatorial Indian Ocean (West, Central and East). Elemental (Li:Ca, Sr:Ca, Ba:Ca, Mg:Ca and Mn:Ca) and stable isotopic (δ13C, δ18O) signatures were used, from individuals captured in 2018 and 2019. Otolith Sr:Ca, Ba:Ca, Mg:Ca and δ18O significantly differed among fish from different nurseries, but, in general, the chemical signatures of the three nursery areas largely overlapped. Multivariate analyses of otolith chemical signatures revealed low geographic separation among Central and Eastern nurseries, achieving a maximum overall random forest cross validated classification success of 51%. Cohort effect on otolith trace element signatures was also detected, indicating that variations in chemical signatures associated with seasonal changes in oceanographic conditions must be well understood, particularly for species with several reproductive peaks throughout the year. Otolith microchemistry in conjunction with other techniques (e.g., genetics, particle tracking) should be further investigated to resolve skipjack stock structure, which will ultimately contribute to the sustainable management of this stock in the Indian Ocean.

Published
2021
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22. Benefit-risk associated with the consumption of fish bycatch from tropical tuna fisheries

Author

Rona Arrisol, Antoine Bideau, Emmanuel Chassot, François Le Loc'h, Nathalie Bodin, Fany Sardenne, Marisa Antha, Jean-Marie Munaron, Anaïs Médieu, Fabienne Le Grand, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Seychelles Fishing Authority (SFA) (SFA), Université des Seychelles, Institut de Recherche pour le Développement (IRD), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Health, Toxicology and Mutagenesis, 010501 environmental sciences, Toxicology, 01 natural sciences, Pelagic fish, Hazard quotient, Western Indian ocean, selenium, Child, trace-elements, Fishes, health, General Medicine, Pollution, Eicosapentaenoic acid, methyl mercury, Docosahexaenoic acid, Child, Preschool, IRD, Adult, Fisheries, chemistry.chemical_element, Biology, Diversity of fish, long-chain, Risk Assessment, Animals, Humans, 14. Life underwater, UBO, 0105 earth and related environmental sciences, ciguatera, Tuna, ACL, toxicity, Pelagic zone, food security, Mercury, Contaminant, essential fatty-acids, Mercury (element), Bycatch, Fishery, chemistry, Seafood, DISCOVERY, mercury concentrations, Sharks, Polyunsaturated fatty acids, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

WOS:000593966600014; International audience; Mercury, omega-3 (docosahexaenoic acid, DHA and eicosapentaenoic acid, EPA) and macronutrients (fat and proteins) were quantified on a wet weight (ww) basis in 20 species of fish taken as bycatch in tropical tuna fisheries. Based on a hazard quotient taking into account mercury and omega-3 contents, a benefit-risk assessment for the consumption of these pelagic species was conducted for three people categories: young children, children and adults. All fish bycatch were found to be an excellent source of proteins (min -max = 14.4-25.2 g/100 g fillet), had low omega-6/omega-3 ratios (\textless1, except for silky shark), and had mercury content below the safety limits defined by sanitary agencies. Silky shark and Istiophoridae had the highest mercury contents (min -max = 0.029-0.317 ppm ww). Omega-3 contents were the lowest in silky shark (0.2 0.2 mg/100 g fillet) and the highest in striped marlin (3.6 +/- 3.2 g/ 100 g fillet). Billfishes (Istiophoridae, including striped marlin), minor tunas (Scombridae), and Carangidae had the highest omega-3 contents (min -max = 0.68-7.28 g/100 g fillet). The highest hazard quotient values obtained for silky shark and great barracuda reflected a lower nutritional benefit (i.e., low omega-3 source) than risk (i.e., mercury exposure), making them not advisable for consumption. Eight species had low hazard quotients, and among them cottonmouth jack and flat needlefish were found of high health interest (high protein, moderate fat contents, and low omega-6/omega-3 ratio). A daily serving portion of 85-200 g (according to people category) can be recommended for these species. Batfish, and to a lower extent pompano dolphinfish and brassy chub, can also be consumed safely and would provide greater health benefits than risks. These results advocate for a better access of these species to local populations. (C) 2020 Elsevier Ltd. All rights reserved.

Published
2020
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23. Otolith microchemistry suggests probable population structuring in the Indian Ocean for the broadbill swordfish Xiphias gladius

Author

Darnaude, Audrey M, Labonne, Maylis, Petit, Cécile, Médieu, Anais, Pernak, Marianne, Nikolic, Natacha, Artetxe-arrate, Iraide, Clear, Naomi, Farley, Jessica, Eveson, Paige, Lozano-montes, Hector, Davies, Campbell, and Marsac, Francis

Abstract

Variation in otolith elemental fingerprints was investigated in the broadbill swordfish (Xiphias gladius) to complement genetic data obtained by next generation sequencing in the framework of a collaborative project on population stock structure of tuna, billfish and sharks of the Indian Ocean (PSTBS-IO). Swordfish specimens for this work were sampled in the southwest (SWI), west central (WCI) and southeast (SEI) regions of the Indian Ocean. A total of 70 otoliths (30 from SWI and 20 from each WCI and SEI) were selected and the elemental signatures of their cores were analysed by LA-ICP-MS to investigate potential differences in spawning origin among regions. Among the 15 chemical elements analysed, only Mg, P, Sr, Ba and B were above detection limits and significantly contributed to the variation in otolith core composition. Based on differences in these five elements, three groups of distinct multi-elemental signatures, denoting potentially discrete spawning origins (SpO), were identified using hierarchical clustering based on Euclidian distances. All SpO identified apparently contributed to the swordfish stocks of the three regions sampled, but in different proportions. SpO-1 was the most common spawning source among the fish sampled (49%); it probably corresponds to the swordfish spawning ground located between northeast Australia and Indonesia. SpO-3 was found to provide 34% of the total fish analysed, but mainly in SWI (53%) and WCI (35%). It could correspond to the spawning grounds reported for the species in the central and southwestern Indian Ocean. Lastly, SpO-2, which contributed to only 17% of the total fish analysed (mainly in SEI and WCI), may correspond to the spawning ground previously reported in the northwestern Indian Ocean, off the Somalian coast. Although our results show mixed origins in the fish sampled at each sampling location, the contrast in otolith core fingerprints between SWI and SEI otoliths suggests differences in main spawning origin, at least for the swordfish captured in these two regions of the Indian Ocean. Additional analyses are needed to consolidate these results, as well as information on the spatiotemporal distribution of chemical tracers in the water masses of the Indian Ocean to assign regions to otolith elemental signatures.

Published
2020

24. Benefit-risk associated with the consumption of fish bycatch from tropical tuna fisheries

Author

Sardenne, Fany, Bodin, Nathalie, Médieu, Anais, Antha, Marisa, Arrisol, Rona, Le Grand, Fabienne, Bideau, Antoine, Munaron, Jean-marie, Le Loc’h, François, Chassot, Emmanuel, Sardenne, Fany, Bodin, Nathalie, Médieu, Anais, Antha, Marisa, Arrisol, Rona, Le Grand, Fabienne, Bideau, Antoine, Munaron, Jean-marie, Le Loc’h, François, and Chassot, Emmanuel

Abstract

Mercury, omega-3 (docosahexaenoic acid, DHA and eicosapentaenoic acid, EPA) and macronutrients (fat and proteins) were quantified on a wet weight (ww) basis in 20 species of fish taken as bycatch in tropical tuna fisheries. Based on a hazard quotient taking into account mercury and omega-3 contents, a benefit-risk assessment for the consumption of these pelagic species was conducted for three people categories: young children, children and adults. All fish bycatch were found to be an excellent source of proteins (min‒max = 14.4‒25.2 g/100g fillet), had low omega-6/omega-3 ratios (<1, except for silky shark), and had mercury content below the safety limits defined by sanitary agencies. Silky shark and Istiophoridae had the highest mercury contents (min‒max = 0.029‒0.317 ppm ww). Omega-3 contents were the lowest in silky shark (0.2±0.2 mg/100g fillet) and the highest in striped marlin (3.6±3.2 g/100g fillet). Billfishes (Istiophoridae, including striped marlin), minor tunas (Scombridae), and Carangidae had the highest omega-3 contents (min‒max = 0.68‒7.28 g/100g fillet). The highest hazard quotient values obtained for silky shark and great barracuda reflected a lower nutritional benefit (i.e., low omega-3 source) than risk (i.e., mercury exposure), making them not advisable for consumption. Eight species had low hazard quotients, and among them cottonmouth jack and flat needlefish were found of high health interest (high protein, moderate fat contents, and low omega-6/omega-3 ratio). A daily serving portion of 85‒200 g (according to people category) can be recommended for these species. Batfish, and to a lower extent pompano dolphinfish and brassy chub, can also be consumed safely and would provide greater health benefits than risks. These results advocate for a better access of these species to local populations.

Published
2020
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25. Otolith chemical fingerprints of skipjack tuna (Katsuwonus pelamis) in the Indian Ocean: First insights into stock structure delineation

Author

Artetxe-Arrate, Iraide, primary, Fraile, Igaratza, additional, Farley, Jessica, additional, Darnaude, Audrey M., additional, Clear, Naomi, additional, Rodríguez-Ezpeleta, Naiara, additional, Dettman, David L., additional, Pécheyran, Christophe, additional, Krug, Iñigo, additional, Médieu, Anaïs, additional, Ahusan, Mohamed, additional, Proctor, Craig, additional, Priatna, Asep, additional, Lestari, Pratiwi, additional, Davies, Campbell, additional, Marsac, Francis, additional, and Murua, Hilario, additional

Published
2021
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26. Mercury concentrations in Pacific Ocean tunas are driven by both anthropogenic and natural factors

Author

Médieu, Anaïs, primary, Point, David, additional, Itai, Takaaki, additional, Angot, Hélène, additional, Buchanan, Pearse, additional, Allain, Valérie, additional, Griffiths, Shane, additional, Fuller, Leanne, additional, Gillikin, David, additional, Sonke, Jeroen, additional, Heimbuerger-Boavida, Lars-Eric, additional, Menkes, Christophe, additional, Madigan, Daniel, additional, Tagliabue, Alessandro, additional, Bopp, Laurent, additional, Verheyden, Anouk, additional, and Lorrain, Anne, additional

Published
2021
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28. Stable mercury concentrations of tropical tuna in the south western Pacific ocean: An 18-year monitoring study

Author

Olivier Gauthier, Aurore Receveur, Christopher J. Somes, Christophe E. Menkès, Anaïs Médieu, David Point, David P. Gillikin, Jeremy Collin, Valerie Allain, Anne Lorrain, Heidi Pethybridge, Andrew T. Revill, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Pacific community (SPC), CSIRO Marine and Atmosphere Research [Hobart], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Union College, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Funding was provided by the Pacific Fund VACOPA project and ANR-17-CE34-0010 MERTOX from the French Agence Nationale de la Recherche. The U.S. National Science Foundation funded Union College’s isotope ratio mass spectrometer and peripherals (NSF-MRI #1229258)., ANR-17-CE34-0010,MERTOX,Découvrir l'origine de la toxine methylmercure dans les écosystèmes marins(2017), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC)

Subjects
Skipjack tuna, Health, Toxicology and Mutagenesis, Biomagnification, 0208 environmental biotechnology, Bigeye tuna, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Yellowfin tuna, chemistry.chemical_compound, subtropical gyre, SUD, Methylmercury, Trophic level, fixation, biology, New Caledonia-Fiji region, General Medicine, Pollution, nitrogen deposition, bioaccumulation, in-situ, Environmental chemistry, IRD, Environmental Monitoring, Food Chain, Environmental Engineering, Oceans and Seas, Stable isotope data, trophic position, thunnus-albacares, Phytoplankton, Animals, Environmental Chemistry, 14. Life underwater, UBO, 0105 earth and related environmental sciences, Pacific Ocean, Tuna, ACL, yellowfin tuna, Public Health, Environmental and Occupational Health, atmospheric mercury, risk-assessment, Mercury, General Chemistry, biology.organism_classification, 020801 environmental engineering, chemistry, 13. Climate action, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Water Pollutants, Chemical
Abstract

WOS:000595802200153; International audience; Global anthropogenic mercury (Hg) emissions to the atmosphere since industrialization are widely considered to be responsible for a significant increase in surface ocean Hg concentrations. Still unclear is how those inputs are converted into toxic methylmercury (MeHg) then transferred and biomagnified in oceanic food webs. We used a unique long-term and continuous dataset to explore the temporal Hg trend and variability of three tropical tuna species (yellowfin, bigeye, and skipjack) from the southwestern Pacific Ocean between 2001 and 2018 (n - 590). Temporal trends of muscle nitrogen (delta N-15) and carbon (delta C-13) stable isotope ratios, amino acid (AA) delta N-15 values and oceanographic variables were also investigated to examine the potential influence of trophic, biogeochemical and physical processes on the temporal variability of tuna Hg concentrations. For the three species, we detected significant inter-annual variability but no significant long-term trend for Hg concentrations. Inter-annual variability was related to the variability in tuna sampled lengths among years and to tuna muscle delta N-15 and delta C-13 values. Complementary AA- and model-estimated phytoplankton delta N-15 values suggested the influence of baseline processes with enhanced tuna Hg concentrations observed when dinitrogen fixers prevail, possibly fuelling baseline Hg methylation and/or MeHg bioavailability at the base of the food web. Our results show that MeHg trends in top predators do not necessary capture the increasing Hg concentrations in surface waters suspected at the global oceanic scale due to the complex and variable processes governing Hg deposition, methylation, bioavailability and biomagnification. This illustrates the need for long-term standardized monitoring programs of marine biota worldwide. (C) 2020 Elsevier Ltd. All rights reserved.

Published
2021
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29. Benchmarking Different Treatment Methods for Organic Municipal Solid Waste

Author

Rutz, D., Mergner, R., Janssen, R., Bojan Ribić, Kostic, R., Hadžić, A., Mijić, G., Pukšec, T., Duić, N., Zweiler, R., Doczekal, C., Novakovits, P., Gruevska, A., Antevski, G., Chaloski, M., Mitkovski, D., Petrusevski, K., Cvetkovska, E., Guevara, L. C. L., Rodríguez-Acuña, R., García, A., Médieu, A., and Kazeroni, M.

Subjects
Anaerobic digestion, Beverage industry, Biogas, Biomethane, Catering services, Food industry, Food waste, Municipal solid waste, Source separated waste, Biomass
Abstract

In the EU around 40% of bio-waste (organic fractions of municipal solid waste including food waste) still goes to landfills. In some Member States this waste is almost completely landfilled. An estimation is that about one-third of Europe`s 2020 targets for renewable energy in transport could be met by using biogas produced from bio-waste (including food waste), and around 2% of the EU`s overall renewable energy target could be met if all bio-waste were turned into energy.Modern and environmentally friendly waste management is still not introduced in many European cities and regions. This problem is tackled by the Bin2Grid project which promotes the “food waste to biomethane” concept in four large European cities in order to serve as flagship examples for other cities.The objective of the Bin2Grid project is to support biomethane production and its use in transport by using segregated food waste from the food and beverage industry, catering sector, and from households(MSW) as feedstock. Focus of the Bin2Grid project is on the development of value chain concepts for four European cities: Zagreb (Croatia), Skopje (Macedonia), Malaga (Spain), and Paris (France). The Bin2Grid project highlights the multiple environmental benefits of source-separate waste collection and conversion of that feedstock into biomethane, in comparison to other treatment methods (landfilling, incineration, MBT, composting). A Benchmark Tool was developed by the project and is presented in this paper., Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 204-209

Published
2017
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30. Struggling at the Borders of the City: Environmental Justice and Water Access in the Southern Zone of Cochabamba, Bolivia

Author

Aurore Médieu and Rocio Bustamante

Subjects
Environmental justice, Health, Toxicology and Mutagenesis, Geography, Planning and Development, Management, Monitoring, Policy and Law, Livelihood, Agrarian society, Harm, Geography, Agricultural land, Environmental protection, Urbanization, Dumping, Element (criminal law), Environmental planning
Abstract

In the periphery of the city of Cochabamba, many communities are struggling to retain a diversity of options for their livelihoods and are resisting the illegal urbanization of agricultural land as well as the pollution generated by the dumping of most of the city's waste in the area. The struggle is aimed not only at maintaining the agrarian characteristics of the area and reversing environmental harm but also at drafting municipal plans of an alternative vision of the city that goes beyond an urban metropolis built only of cement and bricks. An important element for the realization of that vision is access to sufficient and clean water needed to carry out domestic and productive activities in better conditions.

Published
2012
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