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Auteur Salvetat, J.; Lebourges-Dhaussy, A.; Travassos, P.; Gastauer, S.; Roudaut, G.; Vargas, G.; Bertrand, A. doi  openurl
  Titre In situ target strength measurement of the black triggerfish Melichthys niger and the ocean triggerfish Canthidermis sufflamen Type Article scientifique
  Année 2020 Publication Revue Abrégée Mar. Freshw. Res.  
  Volume 71 Numéro 9 Pages 1118-1127  
  Mots-Clés (up) acoustics; aggregating devices fads; archipelago; atlantic; behavior; biomass estimation; frequency; north-east Brazil; shore fishes; small tuna; spinner dolphins; swimbladder; target strength-length relationships; tropical ecosystem; tropical tuna; underwater acoustics; underwater video  
  Résumé Triggerfish are widely distributed in tropical waters where they play an important ecological role. The black triggerfish Melichthys niger may be the dominant species around oceanic tropical islands, whereas pelagic triggerfish, such as the ocean triggerfish Canthidermis sufflamen, can assemble around fish aggregating devices (FADs) where they are a common bycatch of tuna fisheries. In this study we combined acoustic and optical recordings to provide the first in situ target strength (TS) measurement of black and ocean triggerfish. Data were collected in the Archipelago of Fernando de Noronha off north-east Brazil. The mean TS of a 27.8-cm-long black triggerfish at 70 and 200 kHz was -39.3 dB re 1 m(2) (CV = 14.0%) and -38.9 dB re 1 m(2) (CV = 14.4%) respectively. The mean TS values of ocean triggerfish (with a size range of 39-44 cm) at 70 and 200 kHz were -36.0 dB re 1 m(2) (CV = 15.7%) and -33.3 dB re 1 m(2) (CV = 14.0%) respectively. This work opens up the field for acoustic biomass estimates. In addition, we have shown that TS values for ocean triggerfish are within the same range as those of small tunas. Therefore, acoustic data transmitted from FADs equipped with echosounders can introduce a bias in tuna acoustic biomass estimation and lead to increased rates of bycatch.  
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  ISSN 1323-1650 ISBN Médium  
  Région Expédition Conférence  
  Notes WOS:000562536400007 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2872  
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Auteur Marsac, F.; Annasawmy, P.; Noyon, M.; Demarcq, H.; Soria, M.; Rabearisoa, N.; Bach, P.; Cherel, Y.; Grelet, J.; Romanov, E. doi  openurl
  Titre Seamount effect on circulation and distribution of ocean taxa in the vicinity of La Perouse, a shallow seamount in the southwestern Indian Ocean Type Article scientifique
  Année 2020 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.  
  Volume 176 Numéro Pages 104806  
  Mots-Clés (up) acoustics; Bathymetry; behavior; chlorophyll; diet; humpback whales; l-adcp; Mesoscale eddies; Mesozooplankton; micronekton; Micronekton; migration; Pelagic longline fisheries; Stomach contents; swordfish xiphias-gladius; tuna; zooplankton  
  Résumé The La Perouse seamount (60 m depth) has so far been poorly studied despite it being a short distance (160 km) from Reunion Island. As part of the MADRidge project, a multidisciplinary cruise was conducted to evaluate the effect of this shallow seamount on the local hydrology and ecology. Current measurements, temperature and chlorophyll-a profiles, and mesozooplankton and micronekton samples were collected between the summit and 35 km away. Micronekton data were supplemented with stomach content of pelagic top predators as well as fisheries statistics from the domestic longline fleet operating from Reunion. Vertical current profiles revealed distinct patterns between the offshore and seamount-flanked stations, giving evidence of topographical induced flow instabilities, notably on its leeward side (west) relative to the east flank. Distinct patterns in temperature and chlorophyll-a vertical profiles suggest the formation of convergent and divergent circulation cells as a result of the irregular and crescent-like summit topography. Spatial differences in zooplankton abundance were detected with higher biovolumes on the leeward flank. The overall acoustic backscatter for micronekton over the summit was weaker than offshore, but highly concentrated in the upper layer. Albacore tuna and swordfish dominate the longline catch west of Reunion, seemingly in association with a deep (900 m) topographic feature. Yet the largest catch is not directly associated with La Perouse which would be too shallow for top predators to aggregate around in the long term. Enhanced levels of phytoplankton or zooplankton enrichment at La Perouse were not demonstrated in this study, nor was there notable diversity of micronekton species. This might explain the relatively limited importance of this seamount to the tuna fisheries in this region.  
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  ISSN 0967-0645 ISBN Médium  
  Région Expédition Conférence  
  Notes WOS:000556810400009 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2850  
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Auteur Zupa, R.; Fauvel, C.; Mylonas, C.C.; Pousis, C.; Santamaria, N.; Papadaki, M.; Fakriadis, I.; Cicirelli, V.; Mangano, S.; Passantino, L.; Lacalandra, G.M.; Corriero, A. doi  openurl
  Titre Rearing in captivity affects spermatogenesis and sperm quality in greater amberjack, Seriola dumerili (Risso, 1810) Type Article scientifique
  Année 2017 Publication Revue Abrégée J. Anim. Sci.  
  Volume 95 Numéro 9 Pages 4085-4100  
  Mots-Clés (up) acute stress; apoptosis; atlantic bluefin tuna; cultured fish; germ cell apoptosis; germ cell proliferation; germ-cell proliferation; greater amberjack; Marine fish; Motility; ovarian-steroid production; rearing in captivity; reproductive-biology; Seriola dumerili; Sperm quality; thunnus-thynnus l.  
  Résumé The greater amberjack, Seriola dumerili (Risso, 1810), is a promising candidate for the diversification of European aquaculture production, but inconsistent reproduction in captivity prevents commercial production. Recent studies showed that greater amberjack confined in sea cages exhibited scarce gonad development and early interruption of gametogenic activity during the reproductive season. The aim of the present study was to improve our understanding of the observed impairment of spermatogenesis. Adult wild and captive-reared males were sampled during 3 different phases of the reproductive cycle: early gametogenesis (EARLY; late April to early May), advanced gametogenesis (ADVANCED; late May to early June), and spawning (SPAWNING; late June to July). Spermatogonial stem cells and proliferating germ cells were identified through the immunohistochemical localization of Pou5f1 and proliferating cell nuclear antigen, respectively. Apoptotic germ cells were identified throughout the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling method. Sperm quality of captive-reared fish was evaluated using computer-assisted sperm analysis. Captive-reared males exhibited seminiferous lobules of a smaller diameter, a precocious and progressive decrease of spermatogonial mitosis, and a high level of apoptosis at the beginning of the reproductive season, concomitant with a many-fold higher 17 beta-estradiol plasma concentration. The motile spermatozoa percentage of captive greater amberjack was lower than in other teleosts, and a drastic decrease of spermatozoa motility duration, velocity, and ATP content occurred along the reproductive season. An abnormal increase of sperm concentration as well as an increase of dead spermatozoa occurred during the SPAWNING phase, probably because of lack of sperm hydration and ejaculation and consequent sperm ageing. The present study demonstrates the extreme susceptibility of greater amberjack to rearing stress and underscores the need for improvement of the rearing and handling procedures to ameliorate gametogenesis dysfunctions in commercial aquaculture production.  
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  ISSN 0021-8812 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2210  
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Auteur Lefevre, S.; Mckenzie, D.J.; Nilsson, G.E. doi  openurl
  Titre Models projecting the fate of fish populations under climate change need to be based on valid physiological mechanisms Type Article scientifique
  Année 2017 Publication Revue Abrégée Glob. Change Biol.  
  Volume 23 Numéro 9 Pages 3449-3459  
  Mots-Clés (up) aerobic scope; coryphaena-hippurus; energy-demand teleosts; gadus-morhua l; gill surface area; growth; makaira-nigricans; marlin tetrapturus-albidus; metabolism; metabolism-size relationship; oxygen consumption; oxygen-consumption; ram ventilation; Respiration; scaling; swimming performance; tuna katsuwonus-pelamis  
  Résumé Some recent modelling papers projecting smaller fish sizes and catches in a warmer future are based on erroneous assumptions regarding (i) the scaling of gills with body mass and (ii) the energetic cost of 'maintenance'. Assumption (i) posits that insurmountable geometric constraints prevent respiratory surface areas from growing as fast as body volume. It is argued that these constraints explain allometric scaling of energy metabolism, whereby larger fishes have relatively lower mass-specific metabolic rates. Assumption (ii) concludes that when fishes reach a certain size, basal oxygen demands will not be met, because of assumption (i). We here demonstrate unequivocally, by applying accepted physiological principles with reference to the existing literature, that these assumptions are not valid. Gills are folded surfaces, where the scaling of surface area to volume is not constrained by spherical geometry. The gill surface area can, in fact, increase linearly in proportion to gill volume and body mass. We cite the large body of evidence demonstrating that respiratory surface areas in fishes reflect metabolic needs, not vice versa, which explains the large interspecific variation in scaling of gill surface areas. Finally, we point out that future studies basing their predictions on models should incorporate factors for scaling of metabolic rate and for temperature effects on metabolism, which agree with measured values, and should account for interspecific variation in scaling and temperature effects. It is possible that some fishes will become smaller in the future, but to make reliable predictions the underlying mechanisms need to be identified and sought elsewhere than in geometric constraints on gill surface area. Furthermore, to ensure that useful information is conveyed to the public and policymakers about the possible effects of climate change, it is necessary to improve communication and congruity between fish physiologists and fisheries scientists.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1354-1013 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2169  
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Auteur Nikolic, N.; Jérôme, M.; Fonteneau, A.; Evano, H.; Verrez-Bagnis, V. url  doi
openurl 
  Titre Identification of skipjack tuna juveniles based on DNA control region sequences and potential spawning area around reunion island Type Article scientifique
  Année 2016 Publication Revue Abrégée Environmental Biology of Fishes  
  Volume 99 Numéro 2 Pages 171-178  
  Mots-Clés (up) Age; dna; juvenile; Reunion island; skipjack tuna  
  Résumé In this study, we confirmed that DNA control region can be used to identify potential spawning area from pelagic juveniles species. We used the mitochondrial DNA control region to identify tuna juveniles predated by common dolphinfish and sampled in surface waters around Reunion Island. These were skipjack juveniles at an early stage (small length and young age). The biological results confirmed the species identification based on DNA analysis. Catch data by longline reveal a higher number of skipjack from October to December around Reunion Island corresponding to the period of our skipjack juvenile sampling  
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  ISSN 0378-1909 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1518  
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