Embryonic and larval development of Corsican brown meagre, Sciaena umbra (Linnaeus 1758), rearing in captivity from the Mediterranean Sea

International audienc

Ontogeny of swimming performance of hatchery‐reared post‐larvae and juvenile fish: a case of two threatened Mediterranean species

International audienc

Effect of Stocking Density on Survival and Growth of Brown Meagre <i>Sciaena umbra</i> (L.) Larvae

Successful aquacultural production of juvenile fish requires that the optimal rearing conditions be applied. However, for many fish species, there is a significant knowledge gap concerning these conditions. In this study, we evaluated the effects of stocking density on the survival and growth of brown meagre, Sciaena umbra (L.), during rearing trials in an experimental hatchery. This research forms part of a feasibility project to improve the aquacultural production of brown meagre. Four initial larval density treatments (5, 10, 30, and 70 larvae per L) were established. At 0, 9, 17, 22, and 25 days post-hatching, we measured the total length, coefficient of variation in length, and specific growth rate. The physicochemical water parameters remained at satisfactory levels for fish culture throughout the experiment. Lower densities promoted better growth in terms of total length, specific growth rate, and survival. We observed a significant negative correlation between larval density and length growth/survival. Thus, the low larval density treatment yielded the highest survival (48.5% ± 3.46%), growth in final total length (11.9 ± 1.09 mm), and specific growth rate (5.13% ± 0.39% per day). Increased stocking density therefore negatively affects growth and survival, reduces homogeneity, but increases the production of S. umbra larvae. This study helps identify optimal aquaculture conditions for maximizing the production of juvenile S. umbra for ecological restoration

Genome sequencing for genetics diagnosis of patients with intellectual disability: the DEFIDIAG study

International audienceIntroduction: Intellectual Disability (ID) is the most common cause of referral to pediatric genetic centers, as it affects around 1-3% of the general population and is characterized by a wide genetic heterogeneity. The Genome Sequencing (GS) approach is expected to achieve a higher diagnostic yield than exome sequencing given its wider and more homogenous coverage, and, since theoretically, it can more accurately detect variations in regions traditionally not well captured and identify structural variants, or intergenic/deep intronic putatively pathological events. The decreasing cost of sequencing, the progress in data-management and bioinformatics, prompted us to assess GS efficiency as the first line procedure to identify the molecular diagnosis in patients without obvious ID etiology. This work is being carried out in the framework of the national French initiative for genomic medicine (Plan France Medecine Genomique 2025).Methods and Analysis: This multidisciplinary, prospective diagnostic study will compare the diagnostic yield of GS trio analysis (index case, father, mother) with the French core minimal reference strategy (Fragile-X testing, chromosomal microarray analysis and Gene Panel Strategy of 44 selected ID genes). Both strategies are applied in a blinded fashion, in parallel, in the same population of 1275 ID index cases with no obvious diagnosis (50% not previously investigated). Among them, a subgroup of 196 patients are randomized to undergo GS proband analysis in addition to GS trio analysis plus the French core minimal reference strategy, in order to compare their efficiency. The study also aims to identify the most appropriate strategy according to the clinical presentation of the patients, to evaluate the impact of deployment of GS on the families' diagnostic odyssey and the modification of their care, and to identify the advantages/difficulties for the patients and their families.Ethics Statement: The protocol was approved by the Ethics Committee Sud Mediterranee I and the French data privacy commission (CNIL, authorization 919361

Atlas de l'estuaire de la Seine

L'atlas de l'estuaire de la Seine est le fruit d'une collaboration entre les chercheurs des universités du Havre et de Rouen et l'Observatoire Population et Habitat de la Ville du Havre. II porte sur un territoire aux contours encore indéterminés mais qui pourrait se concrétiser grâce au franchissement de l'estuaire par le pont de Normandie. L'aménagement, l'environnement, les habitants, les activités, les services urbains, l'attractivité des villes sont abordés sous l'angle des problématiques et des enjeux qui s'expriment actuellement sur cet espace. Ouvrage exploratoire, sa publication inaugure une série de travaux et de recherches qui ne manqueront pas de voir le jour au sein des universités normandes et des institutions locales. Ouvrage de recherche et de prospective, l'atlas de l'estuaire a également l'ambition d'être un outil d'information et de documentation pour tous les décideurs qui s'intéressent de près ou de loin à ce nouveau territoire

The economic, medical and psychosocial consequences of whole genome sequencing for the genetic diagnosis of patients with intellectual disability: The DEFIDIAG study protocol

International audienceIntroduction: Like other countries, France has invested in a national medical genomics program. Among the four pilot research studies, the DEFIDIAG project focuses on the use of whole genome sequencing (WGS) for patients with intellectual disability (ID), a neurodevelopmental condition affecting 1–3% of the general population but due to a plethora of genes. However, the access to genomic analyses has many potential individual and societal issues in addition to the technical challenges. In order to help decision-makers optimally introduce genomic testing in France, there is a need to identify the socio-economic obstacles and leverages associated with the implementation of WGS. Methods and Analysis: This humanities and social sciences analysis is part of the DEFIDIAG study. The main goal of DEFIDIAG is to compare the percentage of causal genetic diagnoses obtained by trio WGS (including the patient and both parents) (WGS T ) to the percentage obtained using the minimal reference strategy currently used in France (Fragile-X testing, chromosomal microarray analysis, and gene panel strategy including 44 ID genes) for patients with ID having their first clinical genetics consultation. Additionally, four complementary studies will be conducted. First, a cost-effectiveness analysis will be undertaken in a subsample of 196 patients consulting for the first time for a genetic evaluation; in a blinded fashion, WGS T and solo (index case, only) genomic analysis (WGS S ) will be compared to the reference strategy. In addition, quantitative studies will be conducted: the first will estimate the cost of the diagnostic odyssey that could potentially be avoidable with first-line WGS T in all patients previously investigated in the DEFIDIAG study; the second will estimate changes in follow-up of the patients in the year after the return of the WGS T analysis compared to the period before inclusion. Finally, through semi-directive interviews, we will explore the expectations of 60 parents regarding genomic analyses. Discussion: Humanities and social sciences studies can be used to demonstrate the efficiency of WGS and assess the value that families associate with sequencing. These studies are thus expected to clarify trade-offs and to help optimize the implementation of genomic sequencing in France. Ethics Statement: The protocol was approved by the Ethics Committee Sud Méditerranée I (June 2019)—identification number: 2018-A00680-55 and the French data privacy commission (CNIL, authorization 919361). Clinical Trial Registration : ( ClinicalTrials.gov ), identifier (NCT04154891)

Stock enhancement or sea ranching? Insights from monitoring the genetic diversity, relatedness and effective population size in a seeded great scallop population (Pecten maximus)

International audienceThe mass release of hatchery-propagated stocks raises numerous questions concerning its efficiency in terms of local recruitment and effect on the genetic diversity of wild populations. A seeding program, consisting of mass release of hatchery-produced juveniles in the local naturally occurring population of great scallops (Pecten maximus L.), was initiated in the early 1980s in the Bay of Brest (France). The present study aims at evaluating whether this seeding program leads to actual population enhancement, with detectable effects on genetic diversity and effective population size, or consists of sea ranching with limited genetic consequences on the wild stock. To address this question, microsatellite-based genetic monitoring of three hatchery-born and naturally recruited populations was conducted over a 5-year period. Results showed a limited reduction in allelic richness but a strong alteration of allelic frequencies in hatchery populations, while genetic diversity appeared very stable over time in the wild populations. A temporal increase in relatedness was observed in both cultured stock and wild populations. Effective population size (Ne) estimates were low and variable in the wild population. Moreover, the application of the Ryman-Laikre model suggested a high contribution of hatchery-born scallops to the reproductive output of the wild population. Overall, the data suggest that the main objective of the seeding program, which is stock enhancement, is fulfilled. Moreover, gene flow from surrounding populations and/or the reproductive input of undetected sub-populations within the bay may buffer the Ryman-Laikre effect and ensure the retention of the local genetic variability