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Auteur Cox, S.L.; Authier, M.; Orgeret, F.; Weimerskirch, H.; Guinet, C.
Titre High mortality rates in a juvenile free-ranging marine predator and links to dive and forage ability Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Ecol. Evol.
Volume 10 Numéro 1 Pages 410-430
Mots-Clés antarctic fur seals; behavior; bio-logging; body condition; early life; foraging ecology; juvenile mortality; Mirounga leonina; mirounga-leonina; population; regularization paths; southern elephant seal; southern elephant seals; survival; survival analyses; variable selection; weaning mass
Résumé High juvenile mortality rates are typical of many long-lived marine vertebrate predators. Insufficient development in dive and forage ability is considered a key driver of this. However, direct links to survival outcome are sparse, particularly in free-ranging marine animals that may not return to land. In this study, we conduct exploratory investigations toward early mortality in juvenile southern elephant seals Mirounga leonina. Twenty postweaning pups were equipped with (a) a new-generation satellite relay data tag, capable of remotely transmitting fine-scale behavioral movements from accelerometers, and (b) a location transmitting only tag (so that mortality events could be distinguished from device failures). Individuals were followed during their first trip at sea (until mortality or return to land). Two analyses were conducted. First, the behavioral movements and encountered environmental conditions of nonsurviving pups were individually compared to temporally concurrent observations from grouped survivors. Second, common causes of mortality were investigated using Cox's proportional hazard regression and penalized shrinkage techniques. Nine individuals died (two females and seven males) and 11 survived (eight females and three males). All but one individual died before the return phase of their first trip at sea, and all but one were negatively buoyant. Causes of death were variable, although common factors included increased horizontal travel speeds and distances, decreased development in dive and forage ability, and habitat type visited (lower sea surface temperatures and decreased total [eddy] kinetic energy). For long-lived marine vertebrate predators, such as the southern elephant seal, the first few months of life following independence represent a critical period, when small deviations in behavior from the norm appear sufficient to increase mortality risk. Survival rates may subsequently be particularly vulnerable to changes in climate and environment, which will have concomitant consequences on the demography and dynamics of populations.
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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 2045-7758 ISBN Médium
Région Expédition Conférence
Notes WOS:000502011200001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2698
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Auteur Vandeputte, M.; Fraslin, C.; Haffray, P.; Bestin, A.; Allal, F.; Kocour, M.; Prchal, M.; Dupont-Nivet, M.
Titre How to genetically increase fillet yield in fish: Relevant genetic parameters and methods to predict genetic gain Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Aquaculture
Volume 519 Numéro Pages 734877
Mots-Clés Aquaculture; Genetics; Heritability; Linear index; Processing yields; Residual fillet weight; Selection; Selection response; Simulation
Résumé Fillet yield (i.e. the proportion of edible muscle in a fish) is a key economic trait for species sold as fillets. Its genetic improvement is complicated by several of its characteristics 1) it is a ratio trait, 2) its numerator (fillet weight) and denominator (body weight) are strongly correlated (correlations in the range 0.89–0.99), 3) it offers little phenotypic variation and 4) it cannot be measured on alive breeding candidates. In a former study, we showed that it could be improved by selection, especially with three selection indices, fillet yield, residual fillet weight and a ratio-specific linear index. However, it is well known that the heritability of ratio traits does not permit a reliable prediction of genetic gains. As predictability of genetic gains is a key requirement to define breeding programs, we investigated how genetic gains in fillet yield could be predicted by the genetic parameters of fillet yield, of residual fillet weight and of the component traits of the linear index. To this end, we compared simulated genetic gains with those estimated by classical prediction methods. This was done using real sets of genetic parameters obtained in nine populations of rainbow trout, European sea bass, gilthead sea bream and common carp. We show that the genetic parameters of fillet yield cannot be used to reliably predict genetic gains in fillet yield. Conversely, selection index theory using a linear index, combining either fillet weight and body weight or fillet weight and waste weight, provides almost perfect prediction of gains. Still, it is highly sensitive to the precision of the genetic and phenotypic correlations estimates, which should not be rounded to less than three decimals for fillet weight and body weight, while two decimals are appropriate for fillet weight and waste weight. A simple, reasonably precise alternative to the linear index is the use of residual fillet weight (the residual of the regression of fillet weight on body weight) as a surrogate for fillet yield.
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Volume de collection Numéro de collection Edition
ISSN 0044-8486 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2722
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Auteur Ferrari, S.; Rey, S.; Hoglund, E.; Overli, O.; Chatain, B.; MacKenzie, S.; Begout, M.-L.
Titre Physiological responses during acute stress recovery depend on stress coping style in European sea bass, Dicentrarchus labrax Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Physiol. Behav.
Volume 216 Numéro Pages 112801
Mots-Clés aggressive-behavior; arctic-charr; Behavior; boldness; Brain; brain serotonergic activity; charr salvelinus-alpinus; cortisol; Fish; indicators; monoamines; Personality; Physiology; rainbow-trout; selection; Transcriptomic
Résumé Individual stress coping style (reactive, intermediate and proactive) was determined in 3 groups of 120 pit tagged European seabass using the hypoxia avoidance test. The same three groups (no change in social composition) were then reared according to the standards recommended for this species. Then, 127 days later, individuals initially characterized as reactive, intermediate or proactive were submitted to an acute confinement stress for 30 min. Blood samples were taken to measure plasma cortisol levels 30 min (Stress30) or 150 min (Stress150) after the end of the confinement stress. Individuals were then sacrificed to sample the telencephalon in order to measure the main monoamines and their catabolites (at Stress30 only). Individuals from Stress150 were sampled for whole brain for a transcriptomic analysis. The main results showed that reactive individuals had a lower body mass than intermediate individuals which did not differ from proactive individuals. The physiological cortisol response did not differ between coping style at Stress30 but at Stress150 when intermediate and proactive individuals had recovered pre stress levels, reactive individuals showed a significant higher level illustrating a modulation of stress recovery by coping style. Serotonin turnover ratio was higher in proactive and reactive individuals compared to intermediate individuals and a significant positive correlation was observed with cortisol levels whatever the coping style. Further, the confinement stress led to a general increase in the serotonin turnover comparable between coping styles. Stress150 had a significant effect on target mRNA copy number (Gapdh mRNA copy number decreased while ifrd1 mRNA copy number increased) and such changes tended to depend upon coping style.
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Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0031-9384 ISBN Médium
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Notes WOS:000514255000004 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2751
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Auteur Gueroun, S.K.M.; Molinero, J.C.; Piraino, S.; Daly Yahia, M.N.
Titre Population dynamics and predatory impact of the alien jellyfish Aurelia solida (Cnidaria, Scyphozoa) in the Bizerte Lagoon (southwestern Mediterranean Sea) Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Mediterr. Mar. Sci.
Volume 21 Numéro 1 Pages 22-35
Mots-Clés abundance; asexual reproduction rates; aurita cnidaria; common jellyfish; cyanea-capillata; gullmar fjord; mesozooplankton; moon jellyfish; predation; prey selection; prince-william-sound; Scyphomedusae; SW Mediterranean; tokyo bay; zooplankton
Résumé Understanding the life cycle strategies and predatory impact of alien jellyfish species is critical to mitigate the impact that these organisms may have on local populations, biodiversity, and ultimately on the functioning of food webs. In the Mediterranean Sea, little is known about the dynamics of alien jellyfish, despite this biodiversity hotspot being one of the most threatened areas by increasing numbers of alien jellyfish. Here, we investigated the population dynamics and predatory impact of a non-indigenous scyphomedusa, Aurelia solida Browne 1905, in the Bizerte Lagoon, Tunisia. The study was based on bimonthly surveys performed over two consecutive years, from November 2012 to August 2014. Field observations showed that the planktonic phase of A. solida occurs from winter to early summer. Prey composition was investigated by means of gut content and field zooplankton analyses. Calanoid copepods, mollusc larvae, and larvaceans represented the main food items of A. solida. To determine the jellyfish feeding rate and their predatory impact on zooplankton populations, the digestion time for zooplankton prey was assessed at three different temperatures: 13, 18, and 23 degrees C in laboratory conditions, corresponding to the average range of temperatures encountered by A. solida in the Bizerte Lagoon. We found that A. solida consumed 0.5-22.5% and 0.02-37.3% of the daily zooplankton standing stock in 2013 and 2014, respectively. These results indicate a non-negligible but restricted seasonal grazing impact on some mesozooplankton groups, explained by the relatively short lifespan of the medusa stage (5-6 months).
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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 1108-393x ISBN Médium
Région Expédition Conférence
Notes WOS:000524248700003 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2773
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Auteur Rey, C.; Darnaude, A.; Ferraton, F.; Guinand, B.; Bonhomme, F.; Bierne, N.; Gagnaire, P.-A.
Titre Within-Generation Polygenic Selection Shapes Fitness-Related Traits across Environments in Juvenile Sea Bream Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Genes
Volume 11 Numéro 4 Pages 398
Mots-Clés antagonistic pleiotropy; fitness trade-off; habitat association; juvenile growth; polygenic scores; RAD-sequencing; spatially varying selection
Résumé Understanding the genetic underpinnings of fitness trade-offs across spatially variable environments remains a major challenge in evolutionary biology. In Mediterranean gilthead sea bream, first-year juveniles use various marine and brackish lagoon nursery habitats characterized by a trade-off between food availability and environmental disturbance. Phenotypic differences among juveniles foraging in different habitats rapidly appear after larval settlement, but the relative role of local selection and plasticity in phenotypic variation remains unclear. Here, we combine phenotypic and genetic data to address this question. We first report correlations of opposite signs between growth and condition depending on juvenile habitat type. Then, we use single nucleotide polymorphism (SNP) data obtained by Restriction Associated DNA (RAD) sequencing to search for allele frequency changes caused by a single generation of spatially varying selection between habitats. We found evidence for moderate selection operating at multiple loci showing subtle allele frequency shifts between groups of marine and brackish juveniles. We identified subsets of candidate outlier SNPs that, in interaction with habitat type, additively explain up to 3.8% of the variance in juvenile growth and 8.7% in juvenile condition; these SNPs also explained significant fraction of growth rate in an independent larval sample. Our results indicate that selective mortality across environments during early-life stages involves complex trade-offs between alternative growth strategies.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2784
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