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Auteur Alfonso, S.; Sadoul, B.; Cousin, X.; Begout, M.-L. doi  openurl
  Titre Spatial distribution and activity patterns as welfare indicators in response to water quality changes in European sea bass, Dicentrarchus labrax Type Article scientifique
  Année 2020 Publication Revue Abrégée Appl. Anim. Behav. Sci.  
  Volume 226 Numéro Pages Unsp-104974  
  Mots-Clés ammonia toxicity; atlantic salmon; avoidance-behavior; behavioral-responses; Behaviour; current issues; Fish; hyperoxia; hypoxia tolerance; marine fish; rainbow-trout; Stress; stress-response; Water quality; Welfare  
  Résumé In aquaculture, fish are exposed to unavoidable stressors that can be detrimental for their health and welfare. However, welfare in farmed fish can be difficult to assess, and, so far, no standardized test has been universally accepted as a welfare indicator. This work contributes to the establishment of behavioural welfare indicators in a marine teleost in response to different water quality acute stressors. Groups of ten fish were exposed to high Total Ammonia Nitrogen concentration (High TAN, 18 mg.L-1), Hyperoxia (200 % O-2 saturation), Hypoxia (20 % O-2 saturation), or control water quality (100% O-2 saturation and TAN < 2.5 mg.L-1) over 1 hour. Fish were then transferred in a novel environment for a group behaviour test under the same water quality conditions over 2 hours. Videos were recorded to assess thigmotaxis, activity and group cohesion. After this challenge, plasma cortisol concentration was measured in a subsample, while individual behavioural response was measured in the other fish using novel tank diving test. Prior to this study, the novel tank diving test was validated as a behavioural challenge indicative of anxiety state, by using nicotine as anxiolytic drug. Overall, all stress conditions induced a decrease in activity and thigmotaxis and changes in group cohesion while only fish exposed to Hypoxia and High TAN conditions displayed elevated plasma cortisol concentrations. In post-stress condition, activity was still affected but normal behaviour was recovered within the 25 minutes of the test duration. Our work suggests that the activity, thigmotaxis and group cohesion are good behavioural indicators of exposure to degraded water quality, and could be used as standardized measures to assess fish welfare.  
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  Langue English Langue du Résumé Titre Original  
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  ISSN 0168-1591 ISBN Médium  
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  Notes WOS:000531095400002 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2794  
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Auteur Blasco, F.R.; Esbaugh, A.J.; Killen, S.S.; Rantin, F.T.; Taylor, E.W.; McKenzie, D.J. doi  openurl
  Titre Using aerobic exercise to evaluate sub-lethal tolerance of acute warming in fishes Type Article scientifique
  Année 2020 Publication Revue Abrégée J. Exp. Biol.  
  Volume 223 Numéro 9 Pages jeb218602  
  Mots-Clés capacity; climate-change; CTmax; hypoxia tolerance; marine fishes; Oreochromis niloticus; oxygen-tensions; performance; Piaractus mesopotamicus; scope; sea bass; temperature; thermal tolerance  
  Résumé We investigated whether fatigue from sustained aerobic swimming provides a sub-lethal endpoint to define tolerance of acute warming in fishes, as an alternative to loss of equilibrium (LOE) during a critical thermal maximum (CTmax) protocol. Two species were studied, Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus). Each fish underwent an incremental swim test to determine gait transition speed (U-GT), where it first engaged the unsteady anaerobic swimming mode that preceded fatigue. After suitable recovery, each fish was exercised at 85% of their own U-GT and warmed 1 degrees C every 30 min, to identify the temperature at which they fatigued, denoted as CTswim. Fish were also submitted to a standard CTmax, warming at the same rate as CTswim, under static conditions until LOE. All individuals fatigued in CTswim, at a mean temperature approximately 2 degrees C lower than their CTmax. Therefore, if exposed to acute warming in the wild, the ability to perform aerobic metabolic work would be constrained at temperatures significantly below those that directly threatened survival. The collapse in performance at CTswim was preceded by a gait transition qualitatively indistinguishable from that during the incremental swim test. This suggests that fatigue in CTswim was linked to an inability to meet the tissue oxygen demands of exercise plus warming. This is consistent with the oxygen and capacity limited thermal tolerance (OCLTT) hypothesis, regarding the mechanism underlying tolerance of warming in fishes. Overall, fatigue at CTswim provides an ecologically relevant sub-lethal threshold that is more sensitive to extreme events than LOE at CTmax.  
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  ISSN 0022-0949 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2817  
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Auteur Blasco, F.R.; McKenzie, D.J.; Taylor, E.W.; Rantin, F.T. doi  openurl
  Titre The role of the autonomic nervous system in control of cardiac and air-breathing responses to sustained aerobic exercise in the African sharptooth catfish Clarias gariepinus Type Article scientifique
  Année 2017 Publication Revue Abrégée Comp. Biochem. Physiol. A-Mol. Integr. Physiol.  
  Volume 203 Numéro Pages 273-280  
  Mots-Clés Adrenergic tone; bass dicentrarchus-labrax; cardiorespiratory interactions; Cholinergic tone; Fishes; Heart rate; heart-rate; hoplerythrinus-unitaeniatus; Hypoxia; oxygen-tensions; rainbow-trout; salmo-gairdneri; Swimming; synbranchus-marmoratus  
  Résumé Clarias gariepinus is a facultative air-breathing catfish that exhibits changes in heart rate (f(H)) associated with air breaths (AB). A transient bradycardia prior to the AB is followed by sustained tachycardia during breath-hold. This study evaluated air-breathing and cardiac responses to sustained aerobic exercise in juveniles (total length similar to 20 cm), and how exercise influenced variations in f(H) associated with AB. In particular, it investigated the role of adrenergic and cholinergic control in cardiac responses, and effects of pharmacological abolition of this control on air-breathing responses. Sustained exercise at 15, 30 and 45 cm s(-1) in a swim tunnel caused significant increases in f(AB) and f(H), from approximately 5 breaths h(-1) and 60 heartbeats min(-1) at the lowest speed, to over 60 breaths h(-1) and 100 beats min(-1) at the highest, respectively. There was a progressive decline in the degree of variation in f(H), around each AB, as f(AB) increased with exercise intensity. Total autonomic blockade abolished all variation in fH during exercise, and around each AB, but f(AB) responses were the same as in untreated animals. Cardiac responses were exclusively due to modulation of inhibitory cholinergic tone, which varied from >100% at the lowest speed to <10% at the highest. Cholinergic blockade had no effect on f(AB) compared to untreated fish. Excitatory beta-adrenergic tone was approximately 20% and did not vary with swimming speed, but its blockade increased f(AB) at all speeds, compared to untreated animals. This reveals complex effects of autonomic control on air-breathing during exercise in C. gariepinus, which deserve further investigation. (C) 2016 Elsevier Inc. All rights reserved.  
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  ISSN 1095-6433 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1714  
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Auteur Brouwer, G.M.; Duijnstee, I. a. P.; Hazeleger, J.H.; Rossi, F.; Lourens, L.J.; Middelburg, J.J.; Wolthers, M. doi  openurl
  Titre Diet shifts and population dynamics of estuarine foraminifera during ecosystem recovery after experimentally induced hypoxia crises Type Article scientifique
  Année 2016 Publication Revue Abrégée Estuar. Coast. Shelf Sci.  
  Volume 170 Numéro Pages 20-33  
  Mots-Clés Bacteria; Benthic foraminifera; C-13 label; communities; Diet shifts; differential response; diversity; Hypoxia; in-situ; Intertidal; Macrofauna; Meiofauna; microphytobenthos carbon; population dynamics; Sediment  
  Résumé This study shows foraminiferal dynamics after experimentally induced hypoxia within the wider context of ecosystem recovery. C-13-labeled bicarbonate and glucose were added to the sediments to examine foraminiferal diet shifts during ecosystem recovery and test-size measurements were used to deduce population dynamics. Hypoxia-treated and undisturbed patches were compared to distinguish natural (seasonal) fluctuations from hypoxia-induced responses. The effect of timing of disturbance and duration of recovery were investigated. The foraminiferal diets and population dynamics showed higher fluctuations in the recovering patches compared to the controls. The foraminiferal diet and population structure of Haynesina germanica and Ammonia beccarii responded differentially and generally inversely to progressive stages of ecosystem recovery. Tracer inferred diet estimates in April and June and the two distinctly visible cohorts in the test-size distribution, discussed to reflect reproduction in June, strongly suggest that the ample availability of diatoms during the first month of ecosystem recovery after the winter hypoxia was likely profitable to A. beccarii. Enhanced reproduction itself was strongly linked to the subsequent dietary shift to bacteria. The distribution of the test dimensions of H. germanica indicated that this species had less fluctuation in population structure during ecosystem recovery but possibly reproduced in response to the induced winter hypoxia. Bacteria seemed to consistently contribute more to the diet of H. germanica than diatoms. For the diet and test-size distribution of both species, the timing of disturbance seemed to have a higher impact than the duration of the subsequent recovery period. (C) 2016 Published by Elsevier Ltd.  
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  ISSN 0272-7714 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2065  
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Auteur Garcon, V.; Karstensen, J.; Palacz, A.; Telszewski, M.; Aparco Lara, T.; Breitburg, D.; Chavez, F.; Coelho, P.; Cornejo-D'Ottone, M.; Santos, C.; Fiedler, B.; Gallo, N.D.; Gregoire, M.; Gutierrez, D.; Hernandez-Ayon, M.; Isensee, K.; Koslow, T.; Levin, L.; Marsac, F.; Maske, H.; Mbaye, B.C.; Montes, I.; Naqvi, W.; Pearlman, J.; Pinto, E.; Pitcher, G.; Pizarro, O.; Rose, K.; Shenoy, D.; Van der Plas, A.; Vito, M.R.; Weng, K. doi  openurl
  Titre Multidisciplinary Observing in the World Ocean's Oxygen Minimum Zone Regions: From Climate to Fish – The VOICE Initiative Type Article scientifique
  Année 2019 Publication Revue Abrégée Front. Mar. Sci.  
  Volume 6 Numéro Pages 722  
  Mots-Clés continental-shelf; demersal fishes; ecosystem; growth; habitat compression; humboldt current system; hypoxia; multidisciplinary; ocean observing system; oxycline; oxygen minimum zones; readiness level; reproduction; responses; variability  
  Résumé Multidisciplinary ocean observing activities provide critical ocean information to satisfy ever-changing socioeconomic needs and require coordinated implementation. The upper oxycline (transition between high and low oxygen waters) is fundamentally important for the ecosystem structure and can be a useful proxy for multiple observing objectives connected to eastern boundary systems (EBSs) that neighbor oxygen minimum zones (OMZs). The variability of the oxycline and its impact on the ecosystem (VOICE) initiative demonstrates how societal benefits drive the need for integration and optimization of biological, biogeochemical, and physical components of regional ocean observing related to EBS. In liaison with the Global Ocean Oxygen Network, VOICE creates a roadmap toward observation-model syntheses for a comprehensive understanding of selected oxycline-dependent objectives. Local to global effects, such as habitat compression or deoxygenation trends, prompt for comprehensive observing of the oxycline on various space and time scales, and for an increased awareness of its impact on ecosystem services. Building on the Framework for Ocean Observing (FOO), we present a first readiness level assessment for ocean observing of the oxycline in EBS. This was to determine current ocean observing design and future needs in EBS regions (e.g., the California Current System, the Equatorial Eastern Pacific off Ecuador, the Peru-Chile Current system, the Northern Benguela off Namibia, etc.) building on the FOO strategy. We choose regional champions to assess the ocean observing design elements proposed in the FOO, namely, requirement processes, coordination of observational elements, and data management and information products and the related best practices. The readiness level for the FOO elements was derived for each EBS through a similar and very general ad hoc questionnaire. Despite some weaknesses in the questionnaire design and its completion, an assessment was achievable. We found that fisheries and ecosystem management are a societal requirement for all regions, but maturity levels of observational elements and data management and information products differ substantially. Identification of relevant stakeholders, developing strategies for readiness level improvements, and building and sustaining infrastructure capacity to implement these strategies are fundamental milestones for the VOICE initiative over the next 2-5 years and beyond.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2702  
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