Age and heat stress as determinants of telomere length in a long-lived fish, the Siberian Sturgeon

Telomeres shorten at each cell division due to the end-replication problem but also in response to oxidative stress. Consequently, telomeres shorten with age in many endotherms, and this shortening is accelerated under stressful environmental conditions. Data in ectotherm vertebrates remain scarce so far, so our goal was to review existing data for fish and to test the influence of age and stress on telomere length in a very long-lived fish, the Siberian sturgeon (Acipenser baerii). Our review of the literature revealed age-related telomere shortening in approximately half of the published studies. In the Siberian sturgeon, we found a significant telomere shortening with age, both at the intraindividual level using red blood cells (−12.5% in 16 mo) and at the interindividual level using cross-sectional samples of fin over an age range of 8 yr. We also found that heat stress (30°C) significantly reduced telomere length by 15.0% after only 1 mo of exposure. Our results highlight that both age and stressful environmental conditions might be important determinants of telomere length in fish

A conceptual framework to help choose appropriate blue nature-based solutions

Biodiversity loss and climate change have severely impacted ecosystems and livelihoods worldwide, compromising access to food and water, increasing disaster risk, and affecting human health globally. Nature-based Solutions (NbS) have gained interest in addressing these global societal challenges. Although much effort has been directed to NbS in urban and terrestrial environments, the implementation of NbS in marine and coastal environments (blue NbS) lags. The lack of a framework to guide decision-makers and practitioners through the initial planning stages appears to be one of the main obstacles to the slow implementation of blue NbS. To address this, we propose an integrated conceptual framework, built from expert knowledge, to inform the selection of the most appropriate blue NbS based on desired intervention objectives and social-ecological context. Our conceptual framework follows a four incremental steps structure: Step 1 aims to identify the societal challenge(s) to address; Step 2 highlights ecosystem services and the underlying biodiversity and ecological functions that could contribute to confronting the societal challenge(s); Step 3 identify the specific environmental context the intervention needs to be set within (e.g. the spatial scale the intervention will operate within, the ecosystem's vulnerability to stressors, and its ecological condition); and Step 4 provides a selection of potential blue NbS interventions that would help address the targeted societal challenge(s) considering the context defined through Step 3. Designed to maintain, enhance, recover, rehabilitate, or create ecosystem services by supporting biodiversity, the blue NbS intervention portfolio includes marine protection (i.e., fully, highly, lightly, and minimally protected areas), restorative activities (i.e., active, passive, and partial restoration; rehabilitation of ecological function and ecosystem creation), and other management measures (i.e., implementation and enforcement of regulation). Ultimately, our conceptual framework guides decision-makers toward a versatile portfolio of interventions that cater to the specific needs of each ecosystem rather than imposing a rigid, one-size-fits-all model. In the future, this framework needs to integrate socio-economic considerations more comprehensively and be kept up-to-date by including the latest scientific information.info:eu-repo/semantics/publishedVersio

Embracing Nature-based Solutions to promote resilient marine and coastal ecosystems

The world is struggling to limit greenhouse gas emissions and reduce the human footprint on nature. We therefore urgently need to think about how to achieve more with actions to address mounting challenges for human health and wellbeing from biodiversity loss, climate change effects, and unsustainable economic and social development. Nature-based Solutions (NBS) have emerged as a systemic approach and an important component of the response to these challenges. In marine and coastal spaces, NBS can contribute to improved environmental health, climate change mitigation and adaptation, and a more sustainable blue economy, if implemented to a high standard. However, NBS have been largely studied for terrestrial – particularly urban – systems, with limited uptake thus far in marine and coastal areas, despite an abundance of opportunities. Here, we provide explanations for this lag and propose the following three research priorities to advance marine and coastal NBS: (1) Improve understanding of marine and coastal biodiversity-ecosystem services relationships to support NBS better designed for rebuilding system resilience and achieving desired ecological outcomes under climate change; (2) Provide scientific guidance on how and where to implement marine and coastal NBS and better coordinate strategies and projects to facilitate their design, effectiveness, and value through innovative synergistic actions; (3) Develop ways to enhance marine and coastal NBS communication, collaboration, ocean literacy and stewardship to raise awareness, co-create solutions with stakeholders, boost public and policy buy-in, and potentially drive a more sustained investment. Research effort in these three areas will help practitioners, policy-makers and society embrace NBS for managing marine and coastal ecosystems for tangible benefits to people and marine life.The study received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement MaCoBioS (contract no 869710), FutureMARES (contract no 869300) and REST-COAST (contract no 101037097).info:eu-repo/semantics/publishedVersio

Molecular Biomarkers of welfare and sex in farmed Siberian sturgeon (Acipenser baerii)

L'élevage de l'esturgeon est long et principalement orienté vers la production de caviar issu des ovocytes. Afin d'accroître la productivité des aquacultures, il est avantageux de maintenir les femelles avec un minimum de stress et dans un bon état de santé et de bien-être. En effet, l'allocation énergétique durant le développement des poissons entre les différents compartiments physiologiques (croissance, immunité, allostasie, reproduction) déterminera en partie le taux de croissance, le risque de maladies ou encore la quantité et la qualité d'ovocytes produits. Cette thèse traite de biomarqueurs dit de réponse cellulaire au stress, de l'immunité et du stress oxydatif qui permettent d'évaluer le stress, l'état de santé et le bien-être des esturgeons. Un protocole expérimental destiné à produire un gradient de conditions de bien-être, basé sur une complémentation alimentaire et une mise à l'épreuve est présenté en détails et le traitement des résultats à l'aide d'analyses uni- et multi-variées est discuté. Ces données sont aussi placées dans un contexte plus général de travaux effectués en élevage.S'il est intéressant d'avoir des esturgeons en bonne santé en élevage, il est aussi pertinent de sélectionner au plus tôt les femelles. Actuellement, il est nécessaire d'attendre plusieurs années avant de diriger les mâles vers la filière chair et de poursuivre l'élevage des femelles jusqu'à la production de caviar. En effet, les gonades des juvéniles sont indifférenciables et il n'y a pas de dimorphisme sexuel. Cependant, le sexe des esturgeons est très certainement déterminé par la génétique. Cette thèse propose plusieurs méthodologies pour identifier un marqueur génétique du sexe exploitable sur des juvéniles âgés de 3 mois.Sturgeon farming is long and mainly directed toward the caviar production from oocytes. To increase aquaculture productivity, it is advantageous to raise females with little stress and in a good health status and welfare. Indeed, the energy allocation during fish development between different physiological compartments (growth, immunity, allostasis, reproduction) partly determines the growth rate, the risk of disease as well as the quantity and quality of oocytes. This thesis deals with biomarkers of cellular stress response, immunity and oxidative stress to assess stress, health and welfare of sturgeon. An experimental design designed to produce a gradient of welfare conditions which is based on a dietary supplementation and a stress is presented and data analysis using uni- and multivariate analyzes is discussed. These results are also placed in a broader context from experiments in aquaculture conditions.While it is interesting to raised sturgeon in good welfare, it is also relevant to select females as soon as possible. Currently, it's necessary to wait several years before moving male to the flesh production and to continue the raising of females until caviar production. Indeed, gonads of juveniles are indistinguishable and there is no sexual dimorphism. Meanwhile the sex of sturgeon is certainly determined by genetics and this thesis presents several methodologies to identify a genetic sex marker exploitable on three month old juveniles

Assessment of the accuracy of physiological blood indicators for the evaluation of stress, health status and welfare in Siberian sturgeon (Acipenser baerii) subject to chronic heat stress and dietary supplementation

Abstract There is growing interest in the evaluation of stress, health and welfare of farm-raised fish. However, there is no scientific consensus about the methodology that is used to assess them. Sturgeon aquaculture is a recent industry with increasing interest in the production of caviar, which is characterized by high turnover and costs. To improve aquaculture efficiency, this study was conducted on routine blood samples, taken from Siberian sturgeon (Acipenser baerii), to test the robustness of using only physiological indicators to assess heat stress, health, and welfare. Sampling was performed after 1 month of prebiotic dietary supplementation followed by 4 weeks of sublethal heat stress. Data interpretation was achieved with a multivariate statistical tool. The expression of heat shock proteins (HSP) was assessed for the first time in sturgeon erythrocytes. Hsp70 and hsp90 expression was triggered by both stress and dietary supplementation. Indicators of non-specific immunity were modified mainly by stress. Complement activity increases with stress while lysozyme activity decreases, but to a lesser extent in supplemented fish. The antioxidant capacity increases with stress while oxidant metabolites decrease and overall oxidative stress was lower for fish that received dietary supplementation. The positive impact of dietary supplementation on health status was observable after a stress challenge. A principal component analysis was used to combine all the measured parameters and to observe patterns in physiological fish status. The four experimental groups of fish were clearly discriminated with this statistical tool. Physiological indicators from blood samples may enable heat stress, health, and welfare to be assessed in Siberian sturgeon

Effect of water temperature increase on HO-1 expression in European sea bass (Dicentrarchus labrax L.) tissues.

International audienceOne of the most pertinent environmental factors influencing the marine organism life is temperature. It has been demonstrated that an increase of temperature is able to induce the synthesis of heat shock proteins (HSP). In this study we investigated the expression of HO-1 mRNA, also referred to as HSP32, in different tissues of European sea bass (Dicentrarchus labrax, L.) at several time points after increased temperature exposure (from 12degC to 30degC). Our results showed that HO-1 was not expressed in gills, heart, muscle and brain while it was expressed at a basal level in intestine. In liver, spleen and kidneys, HO-1 expression was influenced by temperature increases. In the spleen, we found a significant decrease of the HO-1 expression at the end of 4 weeks. In kidneys a very fast collapse of HO-1 expression level was recorded reaching null value as soon as one hour after exposure to 30degC. In liver, HO-1 expression increased from one hour of exposure to 30degC confirming HO-1 involvement to heat shock response in this organ. This increasing trend reached a 4.5-fold higher value than the initial level after 4 weeks

EFFECTS OF WATER TEMPERATURE INCREASE AND HEAVY METALS CONTAMINATION ON WAP65 GENE EXPRESSION IN SEA BASS (Dicentrarchus labrax) LIVER

International audienceIt has been previously demonstrated that "Warm temperature Acclimation-related 65kD Protein" (WAP65) is involved in temperature acclimation, response to intoxication and infection, as well as in development. The expression of wap65-1 was investigated in the liver of European sea bass (Dicentrarchus labrax) during exposure to the increased temperature (from 12 °C to 30 °C) and during intoxication with four heavy metals: lead, cadmium, copper and zinc. Post temperature increase wap65 expression was highest after one hour at 30 °C. After 1 to 4 weeks at 30 °C wap65 transcript levels did not differ from the 12°C control group, similar to observations regarding the heat shock protein, hsp70. Upregulation of wap65 was detected after treatment (intoxication) with cadmium (0.5 μg/l). In contrast, a slight, but significant down regulation of wap65 was seen after copper (5 μg/l) intoxication. These data indicate that functional analyses of WAP65 are needed to understand the differential regulation of this gene by metals. The role of WAP65 may be similar to that of HSP70, which has generalized functions in responding to certain stressors and maintaining normal cell physiology

In situ spine sampling and Inter-Simple Sequence Repeat (ISSR) PCRs proved relevant methods for molecular studies on the sea urchin Paracentrotus lividus

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Recruitment and Growth of the Fan Mussel Pinna nobilis in the Montenegrin Adriatic Coast and Comparison with the Western Mediterranean

In this study, the comparative results of the fan mussel Pinna nobilis larvae collection during 3 years (2016–2019) on the sites of the Montenegrin Adriatic coast and the Western Mediterranean, France are presented. In both countries, growth studies of collected fan mussel juveniles were carried out as well. After 1 year growth measurement of P. nobilis recruits in their natural habitat on the site Dobrota, Montenegro, mean shell length was 198.58 ± 17.77 mm for the recruits from Sv. Nedjelja and 206.73 ± 16.40 mm for the recruits collected from Ljuta. The growth study carried out in a laboratory tank in France indicated that the mean shell length of P. nobilis recruits after a 9 month period was 100.50 ± 7.59 mm for the recruits from Bomasse, 96.33 ± 11.06 mm from Basse Renette 1, and 95.75 ± 8.45 mm for recruits from Basse Renette 2, respectively. In spite of much larger mean shell lengths obtained in Montenegro, mean monthly growth rate of P. nobilis recruits bred in France was higher due to more stable conditions and access to food within the tank in contrast to variations of environmental parameters in their natural habitat. We have presented first data on P. nobilis recruitment and growth in Montenegro and showed higher growth rate in comparison with the other sites in the Adriatic Sea and Mediterranean. It was shown that the temperature is of high importance for the growth rate of P. nobilis juveniles in their natural habitat due to lower growth during winter. Anthropogenic pressure was the main obstacle for development of P. nobilis populations during the study period, while biological pollution as the main threat for P. nobilis survival will be the subject of further studies in the Montenegrin Adriatic coast