Yves Cherel

French National Centre for Scientific Research | CNRS · Centre d'Etudes Biologiques de Chizé (CNRS & La Rochelle Université)

Elasmobranchs, and particularly skates (Rajiforms), are commonly caught in fisheries worldwide as targeted catch or bycatch. Their life history traits make them particularly sensitive to elevated fishing mortality, especially in slow-growing deep-sea species. Knowledge of their ecology is key to ensure effective conservation and mitigation measures...

According to the principles of community ecology, sympatric species may suffer a selective pressure to decrease their niche overlap through mechanisms of niche partitioning. However, there is still a gap in knowledge of the main drivers influencing niche differentiation, particularly in communities composed by small-sized and inconspicuous species....

The present work explores for the first time the potential of formic acid on the extraction of tiemannite (HgSe) nanoparticles from seabird tissues, in particular giant petrels. Mercury (Hg) is considered one of the top ten chemicals of major public health concern. However, the fate and metabolic pathways of Hg in living organisms remain unknown. M...

Mercury (Hg) is a highly toxic metal that adversely impacts human and wildlife health. The amount of Hg released globally in the environment has increased steadily since the Industrial Revolution, resulting in growing contamination in biota. Seabirds have been extensively studied to monitor Hg contamination in the world's oceans. Multidecadal incre...

[This corrects the article DOI: 10.3389/fphys.2022.1038064.].

Non-conventional stable isotopes have received increasing attention in the past decade to investigate multi-level ecological connections from individuals to ecosystems. More recently, isotopes from trace and non-nutrient elements, potentially toxic (i.e., Hg), have also been recognized of great significance to discriminate sources, transports, and...

The use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960’s, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species le...

The subantarctic white-headed petrel is unique amongst Procellariidae by its biennial breeding frequency. Its food and feeding ecology is poorly known with limited available bio-logging data and no dietary and isotopic information. Our goal was to detail its prey species and isotopic niche at Kerguelen Islands, which is the most important breeding...

Seabirds play important roles as marine ecosystem sentinels. Studying their at-sea ecology is essential for understanding how environmental variability affects their populations. However, the at-sea ecology of small-sized temperate seabirds remains poorly studied. We explored the at-sea ecology of the Critically Endangered MacGillivray’s prion Pach...

Understanding the processes structuring communities is a fundamental goal in ecology and conservation biology. Seabirds are commonly used as sentinels of marine ecosystems, but there is a lack of quantitative information providing a synoptic view of their community structure and of its underlying mechanisms. We used stable isotope analysis of chick...

Penguins lost the ability to fly more than 60 million years ago, subsequently evolving a hyper-specialized marine body plan. Within the framework of a genome-scale, fossil-inclusive phylogeny, we identify key geological events that shaped penguin diversification and genomic signatures consistent with widespread refugia/recolonization during major c...

Niche theory predicts that to reduce competition for the same resource, sympatric ecologically similar species should exploit divergent niches and segregate in one or more dimensions. Seasonal variations in environmental conditions and energy requirements can influence the mechanisms and the degree of niche segregation. However, studies have overlo...

Mercury (Hg) is a toxic trace element widely distributed in the environment, which particularly accumulates in top predators, including seabirds. Among seabirds, large gulls (Larus sp) are generalist feeders, foraging in both terrestrial and marine habitats, making them relevant bioindicators of local coastal Hg contamination. In the present study,...

Coastal ecosystems are among the most diverse and productive systems on earth, but they are threatened by various anthropogenic pressures. To understand the magnitude of these constraints on biodiversity, it is essential to assess habitat use of coastal species, which can be challenging in the complex matrix of habitats in coastal environments. The...

Even in areas as remote as the Southern Ocean, marine organisms are exposed to contaminants that arrive through long-range atmospheric transport, such as mercury (Hg), a highly toxic metal. In previous studies in the Southern Ocean, inter-specific differences in Hg contamination in seabirds was generally related to their distribution and trophic po...

Seabirds are central place foragers, relying on prey that is patchily distributed and of variable predictability. Species travelling at a high energetic cost are more strongly dependent on spatially predictable prey. This is the case for diving petrels Pelecanoides spp., which are small Procellariiformes that feed by pursuit diving and travel by fl...

Beaks are among the few hard parts of coleoid cephalopods and are informative for species identification. Although mandible shape has been shown to be adaptive in many vertebrate taxa, it has been suggested that the shape of coleoid beaks does not bear any ecological signal. Yet, previous studies only explored beak shape in 2D and none have provide...

Cephalopods are an important component of Southern Ocean food webs, but aspects of their trophic ecology remain unresolved. Here, we used archived squid (order Teuthida) beaks, collected from stomach contents of predators at Macquarie and Kerguelen Islands, to investigate the trophic structure within an assemblage of pelagic squids ( Alluroteuthis...

Individual heterogeneity in foraging behaviour determines how individuals and populations respond to changes in the availability and distribution of resources. Antarctic krill Euphausia superba is a pivotal species in Southern Ocean food webs and an important target for Southern Ocean fisheries. Changes in its abundance could dramatically impact ma...

Per and polyfluoroalkyl substances (PFASs) are found in Antarctic wildlife, with high levels in the avian top predator south polar skua (Catharacta maccormicki). As increasing PFAS concentrations were found in the south polar skua during the breeding season in Antarctica, we hypothesised that available prey during the breeding period contributes si...

Mercury contamination is a major threat to the global environment, and is still increasing in some regions despite international regulations. The methylated form of mercury is hazardous to biota, yet its sublethal effects are difficult to detect in wildlife. Body condition can vary in response to stressors, but previous studies have shown mixed eff...

Mesopelagic communities are characterized by a large biomass of diverse macrozooplankton and micronekton (MM) performing diel vertical migration (DVM) connecting the surface to the deeper ocean and contributing to biogeochemical fluxes. In the Southern Ocean, a prominent High Nutrient Low Chlorophyll (HNLC) and low carbon export region, the contrib...

In the comments reported by A. Manceau [1], relating to our recent paper on mercury (Hg) species-specific isotopic characterization in giant petrel tissues [2] two critical questions were raised. Firstly, according to A. Manceau, our method of extraction and isolation of nanoparticles was not able to efficiently isolate mercury selenide nanoparticl...

Little is known on the food and feeding ecology of the soft-plumaged petrel Pterodroma mollis, which is the single gadfly petrel Pterodroma spp. with a circumpolar breeding distribution within the Southern Ocean. Our primary goal was to describe its diet at Kerguelen Islands, which is the southernmost breeding locality of the species. Soft-plumaged...

Antarctic marine ecosystems are often considered to be pristine environments, yet wildlife in the polar regions may still be exposed to high levels of environmental contaminants. Here, we measured total mercury (THg) concentrations in blood samples from adult brown skuas Stercorarius antarcticus lonnbergi (n = 82) from three breeding colonies south...

The New Zealand huia (Heteralocha acutirostris) had the most extreme bill sexual dimorphism among modern birds. Given the quick extinction of the species, the cause of the dimorphism could only be hypothesised to reflect different trophic niches and reduce male/female competition. We tested that hypothesis by combining museum specimens, geometric m...

Sexual segregation is common in many species and has been attributed to intra-specific competition, sex-specific differences in foraging efficiency or in activity budgets and habitat choice. However, very few studies have simultaneously quantified sex-specific foraging strategies, at sea distribution, habitat use, and trophic ecology. Moreover, the...

Interspecific introgression can occur between species that evolve rapidly within an adaptive radiation. Pachyptila petrels differ in bill size and are characterised by incomplete reproductive isolation, leading to interspecific gene flow. Salvin’s prion ( Pachyptila salvini ), whose bill width is intermediate between broad-billed ( P. vittata ) and...

Ecologists working with stable isotopes have to deal with complex datasets includ-ingtemporalandspatialreplication,which makes the analysis and the representa-tion of patterns of change challenging, especially at high resolution. Due to the lackof a commonly accepted conceptual framework in stable isotope ecology, the analy-sis and the graphical re...

Understanding the movements of animals that spend much of their life at sea is difficult but important for effective conservation. Determining the at-sea distributions of Macaroni (Eudyptes chrysolophus) and Royal (Eudyptes schlegeli) Penguins poses particular challenges, including their occurrence in remote locations and difficulties in species id...

Niche theory predicts that to reduce competition for the same resource, sympatric ecologically similar species should exploit divergent niches and segregate in one or more dimensions. Seasonal variations in environmental conditions and energy requirements can influence the mechanisms and the degree of niche segregation. However, studies have overlo...

Tiemannite (HgSe) is considered the end-product of methylmercury (MeHg) demethylation in vertebrates. The biomineralization of HgSe nanoparticles (NPs) is understood to be an efficient MeHg detoxification mechanism; however, the process has not yet been fully elucidated. In order to contribute to the understanding of complex Hg metabolism and HgSe...

To comprehensively assess the impacts of agricultural practices on biodiversity in complex landscapes mixing both agricultural habitats and remnants of other (presumably more favorable) types of habitats, a prerequisite is to evaluate to which extent agricultural habitats are actually used by a given species. Here, we tested whether the stable isot...

A prerequisite for environmental and toxicological applications of mercury (Hg) stable isotopes in wildlife and humans is quantifying the isotopic fractionation of biological reactions. Here, we measured stable Hg isotope values of relevant tissues of giant petrels (Macronectes spp.). Isotopic data were interpreted with published HR-XANES spectrosc...

The reproductive success of birds is strongly driven by environmental conditions at different time scales. Thus, during periods of low food availability, breeding success is constrained by the ability of adults to adapt their foraging effort and feeding behaviour to maintain regular incubation shifts and chick provisioning. However, while large sea...

Oceanic frontal zones have been shown to deeply influence the distribution of primary producers and, at the other extreme of the trophic web, top predators. However, the relationship between these structures and intermediate trophic levels is much more obscure. In this paper we address this knowledge gap by comparing acoustic measurements of mesope...

For top consumers in marine environments, trophic discrimination factors (∆¹³C and ∆¹⁵N) between food and consumers’ tissues are expected to be similar among related species. However, few studies conducted in the laboratory indicate a large variability among species, which should be potentially higher in free-ranging animals. Here, we test for diff...

The Kerguelen Plateau is a region of natural iron fertilization in the Southern Ocean, within the typically iron limited High Nutrient Low Chlorophyll (HNLC) waters of the eastward flowing Antarctic Circumpolar Current. Between 26 February and 19 March 2018, the MOBYDICK expedition investigated pelagic ecosystem dynamics in the Kerguelen Island reg...

Marine litter has become a global issue with ‘garbage patches’ documented in all ocean gyres. The Pacific and Atlantic garbage patches have been well described, but there are few empirical data for the Indian Ocean. In the austral summer 2019–2020, we conducted an at-sea survey of macro-litter in the rarely investigated south-west Indian Ocean. Ove...

Cephalopods are an important component of Southern Ocean food webs but studies analysing their habitat and trophic ecology are scarce. Here, we use the Antarctic toothfish Dissostichus mawsoni as a biological sampler of the Southern Ocean's cephalopods in the Ross, Amundsen, and D'Urville Seas. Ten cephalopod taxa were identified in the diet of the...

Vertical distribution and size-dependent migrations of the pelagic tunicate Salpa thompsoni were studied during late summer to early autumn (26th February – 15th March 2018) at contrasting hydrological stations over the Kerguelen Plateau (Southern Indian Ocean). Vertical migrators, such as S. thompsoni, have potentially significant impacts on the b...

A new record of a rare deep-water scorpionfish Ectreposebastes niger (Fourmanoir, 1971), is described from the south-western Indian Ocean. This is the ninth record in the Indian Ocean and the first documented record of this species in the waters of Reunion Island. It is also the first record of this species in the Indian Ocean since 1982. Its conge...

• Technical advances in 3D imaging have contributed to quantifying and understanding biological variability and complexity. However, small, dry‐sensitive objects are not easy to reconstruct using common and easily available techniques such as photogrammetry, surface scanning, or micro‐CT scanning. Here, we use cephalopod beaks as an example as thei...

The research in Southern Ocean cephalopods is always an ongoing work. There were three main reasons to publish an updated book on beaks from Southern Ocean cephalopods: Firstly, our motivation is that the guide is used in the future without providing confusion on species taxonomy, Secondly, various mistakes on the original printed version of this b...

Cephalopods play a major role in marine ecosystems, yet very little is known about the dynamics of their habitat use and trophic ecology across the stages of their life cycle, particularly in the Southern Ocean. Here, we used stable isotope analyses of δ13C (a proxy for foraging habitat) and δ15N (a proxy for trophic position) to investigate the ha...

This study aimed to obtain the first estimates of S. thompsoni population dynamics and growth rates over the Kerguelen Plateau (Southern Indian Ocean). Micronekton, including salps, were repeatedly sampled during late summer to early autumn (26th February – 15th March 2018) at contrasting hydrological stations on the Kerguelen Plateau in the southe...

The present work resolved the long-standing taxonomic problem associated with the enigmatic ?Mastigoteuthis B Clarke, 1980, by demonstrating that these lower beaks correspond to those of the large deep-sea chiroteuthid Asperoteuthis acanthoderma (Lu, 1977). A review of the existing literature listed 22 specimens of A. acanthoderma, but synonymizing...

The sperm whale is the largest toothed whale that feeds almost exclusively on oceanic cephalopods. Since it was actively hunted commercially, considerably more is known about its food than for many other large marine apex predators. However, the use of those unique dietary information is today hampered by out-of-date cephalopod taxonomy. Here, the...

In vivo and in vitro evidence for detoxification of methylmercury (MeHg) as insoluble mercury selenide (HgSe) underlies the central paradigm that mercury exposure is not or little hazardous when tissue Se is in molar excess (Se:Hg > 1). However, this hypothesis overlooks the binding of Hg to selenoproteins, which lowers the amount of bioavailable S...

Methylmercury (MeHg) is considered the most neurotoxic chemical form of mercury. MeHg is produced in aquatic ecosystems from deposited inorganic mercury (iHg), and subsequently bioaccumulates and biomagnifies through the food chain. This causes large predators in the marine environment to injest and accumulate large quantities of this element mainl...

Mercury (Hg) is an environmental contaminant which, at high concentrations, can negatively influence avian physiology and demography. Albatrosses (Diomedeidae) have higher Hg burdens than all other avian families. Here, we measure total Hg (THg) concentrations of body feathers from adult grey-headed albatrosses ( Thalassarche chrysostoma ) at South...

Capital breeders accumulate nutrients prior to egg development, then use these stores to support offspring development. In contrast, income breeders rely on local nutrients consumed contemporaneously with offspring development. Understanding such nutrient allocations is critical to assessing life-history strategies and habitat use. Despite the cont...

Mercury (Hg) is a very toxic metal and its impact on Human health and wildlife is a major concern. On the global scale, the amount of Hg released in the environment has steadily increased since the Industrial Revolution. From both natural and human sources, Hg disperses all over the globe and deposits even in remote areas such as polar oceans. Beca...

This review presents an innovative approach to investigate the teuthofauna from the Southern Ocean by combining two complementary data sets, the literature on cephalopod taxonomy and biogeography, together with predator dietary investigations. Sixty squids were recorded south of the Subtropical Front, including one circumpolar Antarctic (Psychroteu...

The non-breeding period plays a major role in seabird survival and population dynamics. However, our understanding of the migratory behaviour, moulting and feeding strategies of non-breeding seabirds is still very limited, especially for small-sized species. The present study investigated the post-breeding behaviour of three distant populations (Ke...

To mediate competition, similar sympatric species are assumed to use different resources, or the same but geographically separated resources. The two giant petrels (Macronectes spp.) are intriguing in that they are morphologically similar seabirds with overlapping diets and distributions. To better understand the mechanisms allowing their coexisten...

Changes in the foraging environment and at-sea distribution of southern elephant seals from Kerguelen Islands were investigated over a decade (2004–2018) using tracking, weaning mass, and blood δ ¹³ C values. Females showed either a sub-Antarctic or an Antarctic foraging strategy, and no significant shift in their at-sea distribution was detected b...

The non‐breeding period is critical for restoration of body condition and self‐maintenance in albatrosses, yet detailed information on diet and distribution during this stage of the annual cycle is lacking for many species. Here, we use stable isotope values of body feathers (δ13C, δ15N) to infer habitat use and trophic level of non‐breeding adult...

Trace metals such as Cu, Hg, and Zn have been widely investigated in marine ecotoxicological studies considering their bioaccumulation, transfer along trophic webs, and the risks they pose to ecosystems and human health. Comparatively, Li has received little attention, although this element is increasingly used in the high-tech, ceramics/glass, and...

Individual heterogeneity in diet and foraging behaviour is common in wild animal populations, and can be a strong determinant of how populations respond to environmental changes. Within populations, variation in foraging behaviour and the occurrence of individual tactics in relation to resources distribution can help explain differences in individu...

Seabirds accumulate significant amounts of mercury (Hg) due to their long-life span together with their medium to high trophic position in marine food webs. Hg speciation and Hg isotopic analy