Johann Mourier

Université de Montpellier | UM1 · UMR MARBEC

The occurrence and seasonality of the Critically Endangered great hammerhead shark, Sphyrna mokarran , is data deficient in the Central Pacific region. Using photo-identification and laser-photogrammetry, we describe the seasonal population of great hammerhead sharks in the Tiputa pass (Rangiroa atoll) and Tuheiava pass (Tikehau atoll) in the Tuamo...

A perennial criticism of provisioning ecotourism is that it alters the natural behavior and ecology of the target species by providing an artifcial food source. Here we evaluate its impact on the long-term site fdelity patterns of tiger sharks in French Polynesia. We hypothesized that a signifcant impact of provisioning would lead to (1) increases...

Observers of the Polynesian Shark Observatory (ORP), a citizen science network organized mainly through the Polynesian dive centers, collected an unprecedented amount of data from more than 13,916 dives spanning 43% of the islands of French Polynesia between July 8, 2011, and April 11, 2018. The objective for this type of data collection, which is...

Acoustic telemetry has helped overcome many of the challenges faced when studying the movement ecology of aquatic species, allowing to obtain unprecedented amounts of data. This has made it into one of the most widely used methods nowadays. Many ways to analyse acoustic telemetry data have been made available and deciding on how to analyse the data...

Designing appropriate management plans requires knowledge of both the dispersal ability and what has shaped the current distribution of the species under consideration. Here, we investigated the evolutionary history of the endangered gray reef shark (Carcharhinus amblyrhynchos) across its range by sequencing thousands of RADseq loci in 173 individu...

Recent acoustic telemetry positioning systems are able to reconstruct the positions and trajectories of organisms at a scale of a few centimeters to a few meters. However, they present several logistical constraints including receiver maintenance, calibration procedures and limited access to real-time data. We present here a novel, easy-to-deploy,...

Designing appropriate management plans requires knowledge of both the dispersal ability and what has shaped the current distribution of the species under consideration. Here we investigated the evolutionary history of the endangered grey reef shark ( Carcharhinus amblyrhynchos ) across its range by sequencing thousands of RAD-seq loci in 173 indivi...

Knowledge of the drivers of fine-scale spatial ecology in wide-ranging marine species is vital to understand population structuring and conserve threatened species. Movements and habitat use are likely to be strongly influenced by social relationships between individuals, and social units within animal populations may be subject to distinct selecti...

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first globa...

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first globa...

As marine stocks and biodiversity are rapidly declining, the release of hatchery-reared individuals into the wild is a species conservation measure aiming at replenishing stocks of freshwater, anadromous and marine fish species. The aim of this study is to assess for the first time the post-release exploration behaviours, survival and dispersal in...

Social and non-social animals can aggregate at a specific site for various reasons such as reproduction, feeding, or other synchronized patterns of movements. While shark aggregations are well documented, mixed-species aggregations are less studied and therefore poorly understood. To overcome this, a combination of acoustic telemetry and social net...

Social foraging, where animals forage in groups, takes many forms but is less studied in marine predators as measuring social associations in the wild is challenging. We used biologging (activity, cameras and telemetry receivers) sensors to measure social associations and simultaneous behaviour, in white sharks (Carcharodon carcharias) off Guadalup...

Despite our critical dependence on aquatic wildlife, we lack a complete understanding of the drivers of population stability and structure for most fish species. Social network analysis has been increasingly used to investigate animal societies as it explicitly links individual decision-making to population-level processes and demography. While the...

The tourism activities linked to artificial provisioning of blacktip reef sharks (Carcharhinus melanopterus) and pink whiprays (Pateobatis fai) on a specific site in French Polynesia were suddenly and completely stopped due to a COVID-19 lockdown that lasted 6 weeks from March 20 until April 30, 2020. Using both drone footage and underwater countin...

• Knowledge about spatial and temporal variability in the distribution and abundance of predators is necessary to adapt measures to mitigate human–wildlife interactions. • Acoustic telemetry and network analyses were used to investigate the spatial ecology of bull sharks, the species responsible for most shark bites in Reunion Island, one of the wo...

Examining the movement ecology of mesopredators is fundamental to developing an understanding of their biology, ecology and behaviour, as well as the communities and ecosystems they influence. The limited research on the residency and movements of benthic marine mesopredators has primarily used visual tags, which do not allow for the efficient and...

An animal's energy landscape considers the power requirements associated with residing in or moving through habitats. Within marine environments, these landscapes can be dynamic as water currents will influence animal power requirements and can change rapidly over diel and tidal cycles. In channels and along slopes with strong currents, updraft zon...

Temperature and oxygen limit the distribution of marine ectotherms. Haematological traits underlying blood-oxygen carrying capacity are thought to be correlated with thermal tolerance in certain fishes, and this relationship is hypothesised to be explained by oxygen supply capacity. We tested this hypothesis using reef shark neonates as experimenta...

Over the past decade, drones have become a popular tool for wildlife management and research. Drones have shown significant value for animals that were often difficult or dangerous to study using traditional survey methods. In the past five years drone technology has become commonplace for shark research with their use above, and more recently, bel...

Le requin occupe une place à part dans l'imaginaire collectif : celle de prédateur absolu et de tueur qui règne sur les océans. De nombreux clichés nourris par des siècles d'ignorance, relayés par les médias et alimentés par des films comme Les Dents de lamer, de S. Spielberg, ont parachevé la réputation de ces animaux. Pourtant, les morsures sur l...

Background Understanding movement patterns of a species is vital for optimising conservation and management strategies. This information is often difficult to obtain in the marine realm for species that regularly occur at depth. The common sawshark (Pristiophorus cirratus) is a small, benthic-associated elasmobranch species that occurs from shallow...

Sharks play important functional roles in coral reef ecosystems. Studying reef shark populations' spatial ecology also contributes important data for effective conservation planning. The purpose of this study was to define the home range of neonatal blacktip reef sharks (Carcharhinus melanopterus) around Moorea, French Polynesia, and compare estima...

Anthropogenic ocean acidification (OA) is a threat to coral reef fishes, but few studies have investigated responses of high-trophic-level predators, including sharks. We tested the effects of 72-hr exposure to OA-relevant elevated partial pressures of carbon dioxide (pCO2) on oxygen uptake rates, acid–base status, and haematology of newborn tropic...

Social predation allows groups of predators to search for, pursue, and capture prey with greater efficiency than using solitary hunting. During ~3,000 hours of underwater observations of nocturnal shark foraging activity, we report for the first time a heterospecific association between two shark species, with the nature of the interaction ranging...

While the negative effects of consumptive pressures on marine predators are well established, the effects of increasing non-consumptive activities such as wildlife tourism are still understudied. As such, the long-term effects of the provision of bait on shark behaviour are still unclear. Here, we assessed the effects of provi-sioning using a Contr...

Social foraging allows groups of predators to search for, pursue, and capture prey with greater efficiency than using solitary hunting. It can vary in complexity and take many forms ranging from cooperative hunting, to social information sharing and local enhancement (Lang and Farine 2017). Theoretical and empirical studies support the advantages o...

Background Understanding movement patterns of a species is vital for optimising conservation and management strategies. This information is often difficult to obtain in the marine realm for species that regularly occur at depth. The common sawshark (Pristiophorus cirratus) is a small, benthic associated elasmobranch species that occurs from shallow...

Background Understanding movement patterns of a species is vital for optimising conservation and management strategies. This information is often difficult to obtain in the marine realm for species that regularly occur at depth. The common sawshark (Pristiophorus cirratus) is a small, benthic associated elasmobranch species that occurs from shallow...

Globally, the frequency of shark bites is rising, resulting in an increasing demand for shark deterrents and measures to lessen the impact of shark bites on humans. Most existing shark protection measures are designed to reduce the probability of a bite, but fabrics that minimise injuries when a shark bite occurs can also be used as mitigation devi...

Genetic relatedness in animal societies is often a factor that drives the structure of social groups. In the marine world, most studies which have investigated this question have focused on marine mammals such as whales and dolphins. For sharks, recent studies have demonstrated preferential associations among individuals from which social communiti...

In French Polynesia, both currently recognized manta ray species, Mobula alfredi and M. birostris, are observed. Despite being an important cultural asset and generating significant economic benefits through manta ray watching tourism, published data on the ecology and threats to these species in the region are scarce. Based on an 18-year dataset o...

This erratum has been initiated as many corrections which were submitted during proofing were overlooked by vendor.

The role of relatedness in animal societies has received important consideration as a process driving social groups. In the marine world, most studies which have investigated this question have focused on marine mammals such as whales and dolphins. For sharks, recent studies have demonstrated preferential associations among individuals from which s...

Groups or aggregations of animals can result from individuals being attracted to a common resource or because of synchronised patterns of daily or seasonal activity. Although mostly solitary throughout its distribution, white sharks (Carcharodon carcharias) seasonally aggregate at a number of sites worldwide to feed on calorie-rich pinnipeds. At th...

Conservation science is crucial to global conservation efforts, and often involves projects where foreign scientists visit a host country to conduct research. Science can significantly contribute to conservation efforts in host countries. However, poorly conceived and implemented projects can lead to poor conservation outcomes, cause negative impac...

1. Animal movement patterns are increasingly analysed as spatial networks. Currently, structures of complex movements are typically represented as a single-layer (or monoplex) network. However, aggregating individual movements, to generate population-level inferences, considerably reduces information on how individual or species variability influen...

Abstract Distinguishing the factors that influence activity within a species advances understanding of their behavior and ecology. Continuous observation in the marine environment is not feasible but biotelemetry devices provide an opportunity for detailed analysis of movements and activity patterns. This study investigated the detail that calibrat...

The emergence of DNA barcoding and metabarcoding opened new ways to study biological diversity, however, the completion of DNA barcode libraries is fundamental for such approaches to succeed. This dataset is a DNA barcode reference library (fragment of Cytochrome Oxydase I gene) for 2,190 specimens representing at least 540 species of shore fishes...

Many species of groupers form transient fish spawning aggregations (FSAs) that are both spatially and temporally predictable, making them highly vulnerable to fishing. Consequently, many known aggregations have disappeared, making the collection of additional baseline data imperative to inform management actions and decisions that have the capacity...

Now published in Scientific Data doi: 10.1038/s41597-019-0123-5 Open Access: https://www.nature.com/articles/s41597-019-0123-5 The emergence of DNA barcoding and metabarcoding opened new ways to study biological diversity, however, the completion of DNA barcode libraries is fundamental for such approaches to succeed. This dataset is a DNA barcode...

Ontogenetic niche shifts are widespread. However, individual differences in size at birth, morphology, sex, and personalities can cause variability in behavior. As such, inherent inter-individual differences within populations may lead to context-dependent changes in behavior with animal body size, which is of concern for understanding population d...

A novel image analysis‐based technique applied to unmanned aerial vehicle (UAV) survey data is described to detect and locate individual free‐ranging sharks within aggregations. The method allows rapid collection of data and quantification of fine‐scale swimming and collective patterns of sharks. We demonstrate the usefulness of this technique in a...

In recent decades, network analyses have become ubiquitous in ecology, facilitating our understanding of linkages between paired entities, whether it be genes, proteins, individuals, species, or habitats (Blüthgen et al., 2008; Croft et al., 2008; Krause et al., 2007; Proulx et al., 2005; Wey et al., 2008). Network theory (also known as graph theor...

Following the letter in Science by Cramp et al. we raised the issue that RMI was not the first and largest shark sanctuary (created in 2011) in the Pacific, once French Polynesia protected all shark species (except the mako added in 2012) in its entire EEZ in 2006. More important than this anecdotal detail, we also promote the idea of boosting cult...

An animal’s social environment can be both dynamic and complex. Thus, social species often garner fitness benefits through being plastic in their social behavior. Yet, social plasticity can be constrained by an individual’s experience. We examined the influence of early social environment on social behavior in the tree skink (Egernia striolata), a...

To adapt to their environment, organisms can either directly interact with their surroundings or use social information, namely information provided by neighbouring individuals. Social information relates to the external features of surrounding peers, and little is known about its use by solitary species. Here, we investigated the use of social cue...

Accurately estimating contacts between animals can be critical in ecological studies such as examining social structure, predator–prey interactions or transmission of information and disease. While biotelemetry has been used successfully for such studies in terrestrial systems, it is still under development in the aquatic environment. Acoustic tele...

Food web structure is shaped by interactions within and across trophic levels. As such, understanding how the presence and absence of predators, prey, and competitors affect species foraging patterns is important for predicting the consequences of changes in species abundances, distributions, and behaviors. Here, we used plasma δ¹³C and δ¹⁵N values...

Individuals can play different roles in maintaining connectivity and social cohesion in animal populations and thereby influence population robustness to perturbations. We performed a social network analysis in a reef shark population to assess the vulnerability of the global network to node removal under different scenarios. We found that the netw...

Unmanned aerial vehicles (UAVs) are being increasingly used in studies of marine fauna. Here, we tested the use of a UAV (DJI Phantom II®) to assess fine-scale variation in densities of 2 elasmobranchs (blacktip reef sharks Carcharhinus melanopterus and pink whiprays Himantura fai) on reef systems off Moorea (French Polynesia). We flew parallel tra...

L'archipel des Marquises constitue une zone océanique dotée d'une intense activité phytoplancto-nique dont l'origine n'est pas encore clairement identifiée. Cette abondance de phytoplancton induit une richesse trophique exceptionnelle particulièrement favorable à la présence des grands poissons pélagiques. La pêche industrielle dans la ZEE de Polyn...