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Le Croizier G, Lorrain A, Sonke JE, Hoyos-Padilla EM, Galván-Magaña F, Santana-Morales O, Aquino-Baleytó M, Becerril-García EE, Muntaner-López G, Ketchum J, Block B, Carlisle A, Jorgensen SJ, Besnard L, Jung A, Schaal G, Point D. The Twilight Zone as a Major Foraging Habitat and Mercury Source for the Great White Shark. Environ Sci Technol 2020; 54:15872-15882. [PMID: 33238094 DOI: 10.1021/acs.est.0c05621] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The twilight zone contains the largest biomass of the world's ocean. Identifying its role in the trophic supply and contaminant exposure of marine megafauna constitutes a critical challenge in the context of global change. The white shark (Carcharodon carcharias) is a threatened species with some of the highest concentrations of neurotoxin methylmercury (MeHg) among marine top predators. Large white sharks migrate seasonally from coastal habitats, where they primarily forage on pinnipeds, to oceanic offshore habitats. Tagging studies suggest that while offshore, white sharks may forage at depth on mesopelagic species, yet no biochemical evidence exists. Here, we used mercury isotopic composition to assess the dietary origin of MeHg contamination in white sharks from the Northeast Pacific Ocean. We estimated that a minimum of 72% of the MeHg accumulated by white sharks originates from the consumption of mesopelagic prey, while a maximum of 25% derives from pinnipeds. In addition to highlighting the potential of mercury isotopes to decipher the complex ecological cycle of marine predators, our study provides evidence that the twilight zone constitutes a crucial foraging habitat for these large predators, which had been suspected for over a decade. Climate change is predicted to expand the production of mesopelagic MeHg and modify the mesopelagic biomass globally. Considering the pivotal role of the twilight zone is therefore essential to better predict both MeHg exposure and trophic supply to white sharks, and effectively protect these key vulnerable predators.
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Affiliation(s)
- Gaël Le Croizier
- UMR Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées (OMP), 14 avenue Edouard Belin, 31400 Toulouse, France
| | - Anne Lorrain
- Univ Brest, CNRS, Ifremer, LEMAR, 29280 Plouzané, France
| | - Jeroen E Sonke
- UMR Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées (OMP), 14 avenue Edouard Belin, 31400 Toulouse, France
| | - E Mauricio Hoyos-Padilla
- Pelagios-Kakunjá A.C., Sinaloa 1540, Col. Las Garzas, 23070 La Paz, Baja California Sur, México
- Fins Attached: Marine Research and Conservation, 19675 Still Glen Drive, Colorado Springs, Colorado 80908, United States
| | - Felipe Galván-Magaña
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. IPN s/n., 23096 La Paz, Baja California Sur, México
| | | | - Marc Aquino-Baleytó
- Pelagios-Kakunjá A.C., Sinaloa 1540, Col. Las Garzas, 23070 La Paz, Baja California Sur, México
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. IPN s/n., 23096 La Paz, Baja California Sur, México
| | - Edgar E Becerril-García
- Pelagios-Kakunjá A.C., Sinaloa 1540, Col. Las Garzas, 23070 La Paz, Baja California Sur, México
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. IPN s/n., 23096 La Paz, Baja California Sur, México
| | - Gádor Muntaner-López
- Pelagios-Kakunjá A.C., Sinaloa 1540, Col. Las Garzas, 23070 La Paz, Baja California Sur, México
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. IPN s/n., 23096 La Paz, Baja California Sur, México
| | - James Ketchum
- Pelagios-Kakunjá A.C., Sinaloa 1540, Col. Las Garzas, 23070 La Paz, Baja California Sur, México
| | - Barbara Block
- Hopkins Marine Station, Stanford University, Pacific Grove, California 93950, United States
| | - Aaron Carlisle
- School of Marine Science and Policy, University of Delaware, Lewes, Delaware 19958, United States
| | - Salvador J Jorgensen
- Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Lucien Besnard
- Univ Brest, CNRS, Ifremer, LEMAR, 29280 Plouzané, France
| | - Armelle Jung
- Des Requins et Des Hommes (DRDH), BLP/Technopole Brest-Iroise, 15 rue Dumont d'Urville, Plouzané 29860, France
| | | | - David Point
- UMR Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées (OMP), 14 avenue Edouard Belin, 31400 Toulouse, France
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Little M, Hagar H, Zivot C, Dodd W, Skinner K, Kenny TA, Caughey A, Gaupholm J, Lemire M. Drivers and health implications of the dietary transition among Inuit in the Canadian Arctic: a scoping review. Public Health Nutr 2021; 24:2650-68. [PMID: 32914743 DOI: 10.1017/S1368980020002402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The current study undertook a systematic scoping review on the drivers and implications of dietary changes among Inuit in the Canadian Arctic. DESIGN A keyword search of peer-reviewed articles was performed using PubMed, Web of Science, CINAHL, Academic Search Premier, Circumpolar Health Bibliographic Database and High North Research Documents. Eligibility criteria included all full-text articles of any design reporting on research on food consumption, nutrient intake, dietary adequacy, dietary change, food security, nutrition-related chronic diseases or traditional food harvesting and consumption among Inuit populations residing in Canada. Articles reporting on in vivo and in vitro experiments or on health impacts of environmental contaminants were excluded. RESULTS A total of 162 studies were included. Studies indicated declining country food (CF) consumption in favour of market food (MF). Drivers of this transition include colonial processes, poverty and socio-economic factors, changing food preferences and knowledge, and climate change. Health implications of the dietary transition are complex. Micro-nutrient deficiencies and dietary inadequacy are serious concerns and likely exacerbated by increased consumption of non-nutrient dense MF. Food insecurity, overweight, obesity and related cardiometabolic health outcomes are growing public health concerns. Meanwhile, declining CF consumption is entangled with shifting culture and traditional knowledge, with potential implications for psychological, spiritual, social and cultural health and well-being. CONCLUSIONS By exploring and synthesising published literature, this review provides insight into the complex factors influencing Inuit diet and health. Findings may be informative for future research, decision-making and intersectoral actions around risk assessment, food policy and innovative community programmes.
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