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Auteur (up) de Verdal, H.; Mekkawy, W.; Lind, C.E.; Vandeputte, M.; Chatain, B.; Benzie, J.A.H.
Titre Measuring individual feed efficiency and its correlations with performance traits in Nile tilapia, Oreochromis niloticus Type Article scientifique
Année 2017 Publication Revue Abrégée Aquaculture
Volume 468 Numéro Pages 489-495
Mots-Clés bream sparus-aurata; compensatory growth; conversion efficiency; diet environments; Feed conversion ratio; Feed efficiency; Feed intake; fish-meal; food; genetic-improvement; growth; Nile tilapia; rainbow-trout; Repeatability; salmon salmo-salar; selection; Sex
Résumé Estimating individual feed intake of fish held in groups has long been a challenge precluding precise knowledge of the individual variation of feed efficiency (FE) in fish. In this study, counts of the number of feed pellets (1.63 mg on average) eaten by individual tilapia (Oreochromis niloticus) held in 8 mixed sex groups of 15 fish were measured from video recordings made over a period of 10 days where fish were fed twice daily to achieve compensatory growth after 10 days of fasting. The initial body weight of the fish was 9.77 +/- 2.03 g. Accumulated measures of feed intake (FI) over 11 meals were found to achieve 95% repeatability and a high accuracy of estimation of FI. During the FI measurement period, the average fish growth was 12.0 +/- 3.6 g, feed intake was 0.99 g day (-1), and feed conversion ratio (FCR) was 0.86 +/- 0.20. FI differences accounted for 56% of the observed individual growth variations, and 44% was related to individual variations of FE. On average males grew 24.2% faster than females but consumed 12.1% more feed. Males showed an 11.7% better FCR than females, whereas residual feed intake (RFI) differences were not significant between sexes. FCR and RFI were moderately and significantly correlated (0.58 +/- 0.06) but FCR and FI, and body weight gain (BWG) and RFI, were not, highlighting the complex relationships between feed efficiency traits. The approach described here demonstrates a means to accurately investigate FE traits in fish and to assess the potential for their genetic improvement. Statement of relevance: Feed efficiency has strong economic and environmental impact. (C) 2016 Elsevier B.V. All rights reserved.
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ISSN 0044-8486 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1713
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Auteur (up) Escalas, A.; Ferraton, F.; Paillon, C.; Vidy, G.; Carcaillet, F.; Salen-Picard, C.; Le Loc'h, F.; Richard, P.; Darnaude, A.M.
Titre Spatial variations in dietary organic matter sources modulate the size and condition of fish juveniles in temperate lagoon nursery sites Type Article scientifique
Année 2015 Publication Revue Abrégée Estuar. Coast. Shelf Sci.
Volume 152 Numéro Pages 78-90
Mots-Clés coastal lagoon; continental inputs; diet; fish; food webs; fresh-water flow; gilthead sea bream; isotope ratios; lagoon; marine nurseries; nursery; sole solea-solea; sparus-aurata; Stable isotopes; stable-isotopes; trophic ecology
Résumé Effective conservation of marine fish stocks involves understanding the impact, on population dynamics, of intra-specific variation in nursery habitats use at the juvenile stage. In some regions, an important part of the catching effort is concentrated on a small number of marine species that colonize coastal lagoons during their first year of life. To determine the intra-specific variation in lagoon use by these fish and their potential demographic consequences, we studied diet spatiotemporal variations in the group 0 juveniles of a highly exploited sparid, the gilthead seabream (Sparus aurata L), during their similar to 6 months stay in a NW Mediterranean lagoon (N = 331, SL = 25-198 mm) and traced the origin of the organic matter in their food webs, at two lagoon sites with contrasted continental inputs. This showed that the origin (marine, lagoonal or continental) of the organic matter (OM) available in the water column and the sediment can vary substantially within the same lagoon, in line with local variations in the intensity of marine and continental inputs. The high trophic plasticity of S. aurata allows its juveniles to adapt to resulting differences in prey abundances at each site during their lagoon residency, thereby sustaining high growth irrespective of the area inhabited within the lagoon. However, continental POM incorporation by the juveniles through their diet (of 21-37% on average depending on the site) is proportional to its availability in the environment and could be responsible for the greater fish sizes (of 28 mm SL on average) and body weights (of 40.8 g on average) observed at the site under continental influence in the autumn, when the juveniles are ready to leave the lagoon. This suggests that continental inputs in particulate OM, when present, could significantly enhance fish growth within coastal lagoons, with important consequences on the local population dynamics of the fish species that use them as nurseries. As our results indicate that continental OM can represent up to 62% of the flesh of the juveniles originating from these ecosystems, particular care should be taken to preserve or improve the chemical quality of riverine inputs to coastal lagoons. (C) 2014 Elsevier Ltd. All rights reserved.
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Volume de collection Numéro de collection Edition
ISSN 0272-7714 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1192
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Auteur (up) Fiandrino, A.; Ouisse, V.; Dumas, F.; Lagarde, F.; Pete, R.; Malet, N.; Le Noc, S.; de Wit, R.
Titre Spatial patterns in coastal lagoons related to the hydrodynamics of seawater intrusion Type Article scientifique
Année 2017 Publication Revue Abrégée Mar. Pollut. Bull.
Volume 119 Numéro 1 Pages 132-144
Mots-Clés bay; confinement; estuary; Hydromorphological zonations; Mediterranean coastal lagoons; Mixing efficiency; model performance; Numerical model; sparus-aurata; Transport timescale; transport time scales; ulva rigida; venice lagoon; Water renewal; water renewal timescales; wind-driven circulation
Résumé Marine intrusion was simulated in a choked and in a restricted coastal lagoon by using a 3D-hydrodynamic model. To study the spatiotemporal progression of seawater intrusion and its mixing efficiency with lagoon waters we define Marine Mixed Volume (V-MM) as a new hydrodynamic indicator. Spatial patterns in both lagoons were described by studying the time series and maps of VMM taking into account the meteorological conditions encountered during a water year. The patterns comprised well-mixed zones (WMZ) and physical barrier zones (PBZ) that act as hydrodynamic boundaries. The choked Bages-Sigean lagoon comprises four sub-basins: a PBZ at the inlet, and two WMZ's separated by another PBZ corresponding to a constriction zone. The volumes of the PBZ were 2.1 and 5.4 millions m(3) with characteristic mixing timescale of 68 and 84 days, respectively. The WMZ were 123 and 433 millions m(3) with characteristics mixing timescale of 70 and 39 days, respectively. (C) 2017 Elsevier Ltd. All rights reserved.
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0025-326x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2181
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