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Coral Venom and Toxins as Protection Against Crown‐of‐Thorns Sea Star Attack
No full textInternational audienceCrown‐of‐thorns sea star (CoTS) outbreaks are a main cause of hard coral cover decline across the Indo‐Pacific, posing a major threat to the resilience of coral reefs. However, the drivers underlying CoTS feeding on preferred (e.g., Acropora species) versus non‐preferred (e.g., Porites species) are poorly understood. We hypothesised that coral venom may influence CoTS prey preferences. To investigate this hypothesis, we compared the coral venom toxin families across the genomes of preferred ( A. digitifera , A. hyacinthus , A. millepora and A. tenuis ) and non‐preferred ( P. australiensis , P. compressa , P. lutea and P. rus ) prey species of CoTS. We also included one species from each genus inhabiting the Caribbean, where CoTS are absent ( A. cervicornis and P. astreoides ), to broaden our identification of venom constituents shared within each genus and investigate geographic differences. We collected known cnidarian toxins, and along with the cnidarian Tox‐Prot database, used these to identify putative toxins and investigate their phylogeny. The most abundant toxins across all coral species included neurotoxins (kunitz‐type and SCRiPS) and pore‐forming toxins (actinoporins and MAC‐PFs). We found genera‐specific differences with jellyfish toxins (CFXs) only present in Porites species. Similarly, only Acropora species harboured pore‐forming toxins with the aerolysin domain. Two toxin homologues only present in Indo‐Pacific corals (CFX and MAC‐PF homologues) showed evidence of positive selection, suggesting their evolution is shaped by environmental pressures, including exposure to CoTS. These findings provide a foundation for future studies of scleractinian venoms, which have direct applications to assessing reef coral's susceptibility to future CoTS outbreaks and active reef management
Accident de service : l'installation de l'ordinateur avant l'horaire réglementaire de début du télétravail ne relève pas du prolongement normal du service
No full textInternational audienceNote sous TA Marseille, 2 avril 2025, no 220465
SHORT-TERM CHILLED PRESERVATION OF LITOPENAEUS STYLIROSTRIS SPERMATOPHORES
No full textInternational audienceThe blue shrimp Litopenaeus stylirostris is naturally found on the Pacific East coast from northern Mexico to Peru. In the 1970s this species was identified as a good candidate for domestication. It was thus introduced straightaway in French Polynesia, New-Caledonia and Hawaï (Haffray et al., 2025). Nowadays, selective breeding programs are implemented in French Polynesia and New Caledonia. Manual fertilization to ensure controlled mating is common practice. To do so, the sperm mass contained in the spermatophores of the males is sampled and placed on the gonopores of the females for fertilization to occur. In order to ease that process, the aim would be to sample the desirable males whenever they are mature and store their spermatophore in the fridge, waiting for the wanted females to be about to spawn and fertilized thanks to these chilled spermatophores.Material and MethodThe males used in this study were 10 months of age (~ 40 g) and were reared and prepared as breeders according to the practices of the commercial hatchery VAIA (Vairao, Tahiti). Only mature males with two spermatophores (non-melanized) were sampled. In total, 88 spermatophores from 88 different males were placed in a tube within a preservation solution for storage in the fridge (4°C). This solution was a saline calcium-free solution containing antibiotics, as inspired by Nimrat et al., 2020. Spermatophores were assessed for viability every day, starting the next day of the sampling and for two weeks. To do so, a suspension of spermatozoa obtained from the sperm mass from the spermatophores was stained with the pink dye eosine and observed under a light microscope. Unstained cells were considered alive whereas pink-colored cells were considered non-viable.ResultsStatistically, as shown in Figure 1, there was a significative difference in mean viability since the first day of chilled-storage compared to the perfect full viability of the control. However, during the first 5 days, the viability remained stable above around 78% in mean. The viability dropped more noticeably after 8 days of chilled-storage and reached a mean of 37%.Figure 1: Assessment of sperm viability during chill storage of spermatophoresConclusionsFuture work will aim at optimizing the current protocol to sample and preserve the spermatophore (e.g. composition of the solution) so that to keep viability more stable over time and at an even higher level.As such, these results are promising to facilitate the use of Litopenaeus stylirostris males for artificial fertilization in hatcheries, as it provides some flexibility in the operational organization of the mating plans. It can also be a very interesting way to easily provide some male genetic resources to other hatcheries if transportation in chilled conditions does not exceed one week.AcknowledgementsWe feel very indebted towards the DRM who owns the shrimp line and VAIA hatchery in Tahiti financing 100% of the blue shrimp production through a public market with the CAPF: they let us use part of their broodstock in order to conduct the experiment. We warmly thank IsBlue for the mobility grant, the UPF for the training grant, OSO farming, Blue Genetics, Aquapesca and UPRA-NC Crevette for their financial support. We also thank also Ifremer (Vairao) for the place allocated to achieve the sampling of the animals.ReferencesHaffray, P., Enez, F., Mahunon, H., Lorgeoux, B., Blanc, P.P., Genestout, L., Rivaton, A., Bugeon, J., Liautard-Haag, C., Gagnaire, P.-A., Vandeputte, M., 2025. High residual genetic variability in a Pacific blue shrimp Litopenaeus stylirostris population after 36 generations of domestication from only 4 estimated founders. Aquaculture, 609 (742835). https://doi.org/10.1016/j.aquaculture.2025.742835Nimrat, S., Playsin, N., Jong-on, B., Boonthai, T., Vuthiphandchai, V., 2020. Chilled storage of banana shrimp (Fenneropenaeus merguiensis) spermatophores with supplementation of moringa (Moringa oleifera Lam.) extract. Aquaculture Research 51, 3582–3592. https://doi.org/10.1111/are.1469
Life stage-specific habitat use and trophic ecology of the Critically Endangered Great hammerhead (Sphyrna mokarran)
No full textInternational audienceThe great hammerhead (Sphyrna mokarran) is listed as Critically Endangered by the IUCN Red List and is one of the most iconic shark species worldwide. Despite its emblematic status, there are major knowledge gaps regarding its habitat use and ecology -particularly during early life stages. In recent years, however, considerable advances have been made in our understanding of great hammerhead biology -especially in previously data-deficient regions such as the northern Indian Ocean and South Pacific Islands. Here, we review and reassess the literature on the habitat use and dietary ecology of S. mokarran, with specific consideration of these factors across the species life stages. This review provides new key insights into the species' habitat requirements, which are essential to assess its resilience to climate change. Emerging findings suggests that S. mokarran may have more limited dispersal capabilities than previously assumed, exhibiting restricted migratory behavior and a stronger reliance on coastal or insular habitats. Moreover, recent research has begun to describe previously undocumented critical habitats, including mating, pupping, and nursery areas-vital for population recovery. Regional differences in habitat use and diet are becoming evident, highlighting the importance of regionspecific assessments of vulnerability and population-level conservation strategies. In this context, some regions-such as the South Pacific-may play a particularly important role in the species' survival and thus merit increased research and conservation efforts.Le grand requin-marteau (Sphyrna mokarran), classé en « En Danger Critique d'Extinction » par la Liste rouge de l'UICN, figure parmi les espèces de requins les plus emblématiques au monde. Malgré ce statut, d'importantes lacunes persistent quant à son utilisation de l’habitat et à son écologie, en particulier durant les premiers stades de vie. Cependant, ces dernières années, des avancées notables ont été réalisées, notamment dans des régions historiquement peu étudiées telles que le nord de l’océan Indien et les îles du Pacifique Sud. Cette revue dresse un état des connaissances actuelles sur l’écologie spatiale et trophique de S. mokarran à travers les différentes phases de son cycle de vie. Elle apporte de nouveaux éclairages sur les exigences écologiques de l’espèce, essentielles pour évaluer sa résilience face aux pressions environnementales et au changement climatique. Les résultats récents indiquent que S. mokarran pourrait avoir une capacité de dispersion plus restreinte qu’attendu, caractérisée par un comportement migratoire limité et une forte dépendance aux habitats côtiers et insulaires. Par ailleurs, des zones critiques nécessaires au maintien des populations, – incluant les aires de reproduction, de mise-bas et de nurserie – commencent à être identifiées et décrites. Enfin, la variabilité régionale observée dans l’utilisation de l’habitat et le régime alimentaire met en évidence la nécessité d’approches de conservation adaptées à chaque région. Certaines zones, comme le Pacifique sud-central, pourraient ainsi jouer un rôle déterminant dans la survie à long terme de l’espèce et mériteraient donc des efforts accrus de recherche et de conservation.HA'APOTORA'A PARAU : TE TAUMATAROA (Tahitien) / TAMATAROA (Paumotu) ’Ua riro te Taumataroa (Sphyrna mokarran), o tei tāpupu hia i roto i te mau ’ānimara ’ati moura’a i roto mai i te tāpura ’ura a te UICN, ei ma’o pihi ’ā’ia i roto i te ao nei. Noa atu ra i terā ti’ara’a tōna, te tāmau noa ra ā te mau rava’i ’ore i roto i te mau ’imira’a , mai te parau o tōna nohora’a e tōna ’ihiheiora, mai te mau tuha’a mātāmua o tōna orara’a. Ati’ara, ’ua nu’u rahi i roto i te mau mā’imira’a, i roto i te mau vaeha’a moana o tei ’ore ’imi’imi hia mai te moana initia e tae noa atu i roto te tahi mau ta’a fenua nō Patifita ’apato’a. I roto i teie ve’a, te tāpura hia nei te mau pu’e ite i ni’a i te mau vahi o tōna mau tere e tae noa atu i te mā’a tā te Taumataroa e ’amu nei i roto i tōna orara’a.Te poro’i ato’a teie ve’a i te mau ha’amaramaramara’a pāpū maita’i i ni’a i te mau titaura’a e ti’a ia rave nō te Taumataroa, e faufa’a mau nō te faīto tōna tūora i mua te nē’ira’a o te arutaimareva e tae noa atu i te mau tauira’a ’ahuāra’i.’Ua fa’aitie mai te mau mā’imira’a ’āpī te purara’a ha’iha’i roa tō te Taumataroa, e tamau ’oia i te horohoro pinepine i te mau vaeha’a piri fenua.Te ha’amata hia nei i teie taime i te ’ite hi i te mau vāhi e fa’aea tamau ai te mau Taumataroa, te mau vāhi fa’a’āera’a, te mau vāhi fanaura’a e te mau vāhi hi’ira’a fanau’a. ’Ua pāpū i teie mahana, nō te pāruru pāpū i te Taumataroa, e mea ti’a ia fa’atano hia te mau ravera’a ato’a ia au i tōna mau vaeha’a moana, tōna mau nohora’a, e tāna mau mā’a. I roto te mau vaeha’a moana nō Patifita ’apato’a, e ti’ara’a faufa’a mau ā tō te ta’ata, i te tāmau i te pāruru i te Taumataroa i roto i te tau atea, e ’ia tāmau ato’a hia te ’imira’a e te pārurura’a. Traduction: Jonas Tiar
Le lien à la terre dans la fiction océanienne d’expression française
No full textInternational audienceAbstract The link to the land, the place where newborn babies’ placentas are traditionally buried in Polynesia, is clearly apparent in L'Ile des rêves écrasés by Chantal T. Spitz, where the announcement of the creation of a missile base at Ruahine causes Tematua an intimate wound. But the land is also a burial place for the dead, and the attack on a pre-European cemetery in Le Bambou noir by Jean-Marc Tera'ituatini Pambrun is one of the causes of the revolt by local residents, supported by the main protagonist, against a luxury hotel project in Punaauia in Tahiti. Some of Déwé Gorodé’s stories also show the extent to which the relationship with the land is at the heart of Kanak identity. A similar dimension can be seen in Paul Tavo's novel Quand le cannibale ricane, in which William, engulfed in alcohol and drugs in Port-Vila, returns to Lamap to re-learn, with his family and friends, the traditional activities of cultivating the land and thus re-forge his Pacific identity.Résumé Le lien à la terre, lieu où l’on enterre traditionnellement en Polynésie le placenta des nouveaux-nés, apparaît nettement dans L'Île des rêves écrasés de Chantal T. Spitz, où l’annonce de la création d’une base de missiles à Ruahine provoque une blessure intime chez Tematua. Mais la terre est aussi un lieu de sépulture des morts, et l’atteinte à un cimetière pré-européen dans Le Bambou noir de Jean-Marc Tera’ituatini Pambrun est une des causes de la révolte des riverains, soutenue par le protagoniste, contre un projet d’hôtel de luxe à Punaauia. Certains récits de Déwé Gorodé montrent par ailleurs à quel point le rapport à la terre est au cœur de l’identité kanak. Une dimension similaire s’observe dans le roman de Paul Tavo intitulé Quand le cannibale ricane ; William, enlisé dans l’alcool et les drogues à Port-Vila, retourne à Lamap pour réapprendre avec ses proches les gestes traditionnels de la culture de la terre et reforger ainsi son identité océanienne.Resumo A ligação com a terra, o local onde as placentas dos bebês recém-nascidos são tradicionalmente enterradas na Polinésia, é claramente aparente em L'Ile des rêves écrasés, de Chantal T. Spitz, onde o anúncio da criação de uma base de mísseis em Ruahine causa uma ferida íntima em Tematua. Mas a terra também é um local de sepultamento para os mortos, e o ataque a um cemitério pré-europeu em Le Bambou noir, de Jean-Marc Tera'ituatini Pambrun, é uma das causas da revolta dos moradores locais, apoiados pelo protagonista principal, contra um projeto de hotel de luxo em Punaauia, no Taiti. Algumas das histórias de Déwé Gorodé também mostram até que ponto a relação com a terra está no centro da identidade kanak. Uma dimensão semelhante pode ser observada no romance Quand le cannibale ricane, de Paul Tavo, no qual William, envolvido em álcool e drogas em Port-Vila, retorna a Lamap para reaprender, com sua família e amigos, as atividades tradicionais de cultivo da terra e, assim, forjar novamente sua identidade do Pacífico
Computations regarding the torsion homology of Oeljeklaus-Toma manifolds
No full textThis article investigates the torsion homology behaviour in towers of Oeljeklaus-Toma (OT) manifolds. This adapts an idea of Silver and Williams from knot theory to OT-manifolds and extends it to higher degree homology groups. In the case of surfaces, i.e. Inoue surfaces of type , the torsion grows exponentially in both (as was established by Braunling) and (our result) according to a parameter which already plays a role in Inoue's classical paper, and we obtain that the torsion vanishes in all higher degrees. This motivates our presented machine calculations for OT-manifolds of higher dimension
Shifting Identities: Women and Travel Narratives in Colonial Oceania: Rose de Freycinet, Titaÿna, Renée Hamon
No full textInternational audienceThis study explores the travel writings of three Francophone authors, Rose de Freycinet, Titaÿna, and Renée Hamon, who, between the nineteenth and early twentieth centuries, inscribed their work within the context of French colonial expansion in Oceania. Far from being limited to exoticism or ethnographic description, their texts constitute genuine spaces of identity negotiation, where the tensions between gender, power, and otherness are constantly redefined. Through their journeys, travel becomes both a symbolic and a geographical displacement, a means of questioning femininity, colonial norms, and the position of the Western subject in relation to the Other. Rose de Freycinet illustrates continuity within transgression, discreetly reconciling her role as a woman with the experience of the sea and of displacement. Titaÿna, by contrast, turns departure into an existential rupture, seeking in elsewhere a radical redefinition of the self. Renée Hamon adopts a critical and lucid posture, aware of the moral complexity of the colonial gaze and of the irreducible distance between the traveler and the societies she encounters. Their writings, marked by ambivalence and fragmentation, shift the boundaries of imperial discourse. Elsewhere becomes both a test of the body, of language, and of perception—a laboratory in which a feminine subjectivity in transit takes shape, neither fully subversive nor entirely compliant. By linking the intimate and the political, these narratives reveal how women could invest travel not as conquest, but as a testing of the self through contact with otherness. These voices, long marginalized, thus contribute to a critical rereading of travel literature and French colonialism, bringing to light a poetics of displacement, dissonance, and transformation.Cette étude explore les récits de voyage de trois autrices francophones, Rose de Freycinet, Titaÿna et Renée Hamon, qui, entre le XIXe et le début du XXe siècle, inscrivent leur écriture dans le contexte de l’expansion coloniale française en Océanie. Loin de se limiter à l’exotisme ou à la description ethnographique, leurs textes constituent de véritables espaces de négociation identitaire où se rejouent les tensions entre genre, pouvoir et altérité. À travers leurs parcours, le voyage devient un lieu de déplacement symbolique autant que géographique, un moyen de questionner la féminité, la norme coloniale et la position du sujet occidental face à l’Autre. Rose de Freycinet illustre la continuité dans la transgression, conciliant discrètement son rôle de femme avec l’expérience de la mer et du déracinement. Titaÿna, au contraire, fait du départ une rupture existentielle, cherchant dans l’ailleurs une redéfinition radicale du moi. Renée Hamon adopte une posture critique et lucide, consciente de la complexité morale du regard colonial et de la distance irréductible entre la voyageuse et les sociétés qu’elle observe. Leurs écritures, marquées par l’ambivalence et la fragmentation, déplacent les frontières du discours impérial. L’ailleurs devient à la fois épreuve du corps, du langage et du regard, un laboratoire où s’élabore une subjectivité féminine en transit, ni totalement subversive ni entièrement conforme. En articulant l’intime et le politique, ces récits révèlent comment les femmes ont pu investir le voyage non comme conquête, mais comme mise à l’épreuve de soi au contact de l’altérité. Ces voix, longtemps marginalisées, participent ainsi à une relecture critique de la littérature viatique et du colonialisme français, en faisant émerger une poétique du déplacement, du désajustement et de la transformation
Préface
No full textInternational audienceCe texte introduit la question des inégalités scolaires en contexte ultramarin. L'auteur retrace l'histoire récente du débat autour de la réussite scolaire en expliquant l'impact exercé par les approches écosystémiques et interactionnistes, notamment en France. Il montre que les contextes les plus marginalisés (dont les Outre-mer et les territoires postcoloniaux) méritent d'être mieux étudiés et que peu de travaux ont analysé en profondeur l'impact qui y a exercé l'héritage colonial sur la structure scolaire et sur le bien être et la réussite des élèves
Genetic Relatedness and Parentage Analysis as a Framework to Enhance Local Conservation Strategies for Marine Species
No full textInternational audienceConservation of marine species faces specific challenges, especially considering the environmental factors and cryptic behaviors that affect organismal dispersal. In the context of conservation genetics, microsatellite markers have been successfully applied in population genetics to assess genetic differentiation and delineate population clusters, helping to identify broader scale conservation needs. Here, we tested the relevance of using microsatellite markers to perform parentage analysis with very little information on a marine sessile organism to inform spatial conservation efforts. Specifically, we investigated the genetic structure of Atrina vexillum, a large marine bivalve, sampled in the lagoon of Bora-Bora. Our primary objective was to sample a significant portion of the population with a stratified underwater survey, which led to the sampling of 1389 individuals, estimated to represent ~80% of the total population. We then screened 30 microsatellite loci to compute a relatedness matrix and assess genetic relationships among individuals. Based on pairwise relatedness values, we computed a UPGMA hierarchical clustering to construct family groups and compared the results with a maximum-likelihood-based parentage analysis implemented in COLONY. In parallel, we also looked for genetic structure using Bayesian clustering with STRUCTURE. We then investigated spatial patterns of genetic relatedness, testing correlations with geographic distances. The distribution of relatedness values indicated a relatively even contribution to reproduction among sampled individuals. Although no population structure was detected using the Bayesian clustering algorithm, we identified multiple family groups, some comprising up to 19 individuals. Spatial analyses showed no significant correlation between genetic relatedness and proximity, except among closely related individuals, who tended to be found in close proximity. Our findings highlight the value of the relatedness-based approach to identify genetic connectivity and reproductive behavior. In A. vexillum, this approach demonstrates the importance of protecting high-density areas where settlement occurs, even though no spatial genetic structure was found within the lagoon