BLANCHETON, J. - P., D'ORBCAS℡, E. R. O. Q. U. E., LEMARIE, G., BREUIL, G., PETOCHI, T., MARINO, G., et al. (2010). Effects of rearing density on sea bass (Dicentrarchus labrax) biological performance, blood parameters and disease resistance in a flow through system. Aquatic Living Resources, 23(1), 109–117.
Résumé: During 84 days, the effects of density on juvenile sea bass (Dicentrarchus labrax) (76 +/- 16 g) were studied in an experimental tank-based flow through system. Performance, stress response and resistance to virus infection were analysed under five stabilized rearing densities: 10, 20, 40, 70 and 100 kg m(-3). Water quality parameters (CO2, total ammonia nitrogen and O-2) were measured and maintained close to the recommended values for farmed sea bass by adjusting water renewal exchange. No significant differences were observed between density treatments, neither on stress response (cortisol) nor susceptibility to nodavirus. With regards to biological performances, the daily feed intake and specific growth rate were significantly lower in fish reared at the 100 kg m(-3) density. Results on the effects of density in sea bass reared in flow through (present study) and in recirculating aquaculture systems (RAS) (Sammouth et al. 2009) were compared as a contribution to the identification of density not affecting health and welfare in farmed sea bass.
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ROQUE D'ORBCASTEL, E., BLANCHETON, J. - P., & AUBIN, J. (2009). Towards environmentally sustainable aquaculture: Comparison between two trout farming systems using Life Cycle Assessment. Aquacultural Engineering, 40(3), 113–119.
Résumé: Life Cycle Assessment(LCA) was applied to evaluate the global environmental impact of two scenarios of trout production systems based on the operational information from an operational farm using a flow through system (FFF) and an experimental pilot low head recirculating system (RSF) located on the same site. The main differences between the environmental balances of the two systems were relative to water use, eutrophication potential and energy use. Independently of the system used, feed is the key indicator in determining the environmental balance (notwithstanding eutrophication potential and water dependence) monitored by fish production, chemical products, buildings and energy consumption. Consequently, when considering the RSF with a lower feed conversion ratio (0.8 versus 1.1 for FTF), the environmental balance of the RSF is more favourable at both global and regional levels, except with regards to energy use. RSF water dependence is 93% lower than the FTF and its eutrophication potential is 26-38% lower due to reduced waste release. On the other hand, at 57,659 MJ per ton of fish produced ( 16 kWh per kg), the RSF consumes 24-40% more energy than the FTF, especially for aeration and water treatment. Nevertheless, the RSF has significant potential for energy reduction through improvements to airlift and biofilter designs which Would reduce RSF energy use to a level similar to that of the FTF (34,869-43,841 MJ per ton of fish produced, corresponding to 10 and 12 kWh respectively). LCA is therefore a powerful tool which can be used on fish farms to define and prioritise the most promising potential improvements to the system. (C) 2008 Elsevier B.V. All rights reserved.
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ROQUE D'ORBCASTEL, E., LEMARIE, G., BREUIL, G., PETOCHI, T., MARINO, G., TRIPLET, S., et al. (2010). Effects of rearing density on sea bass (Dicentrarchus labrax) biological performance, blood parameters and disease resistance in a flow through system. Aquatic Living Resources, 23(1), 109–117.
Résumé: During 84 days, the effects of density on juvenile sea bass (Dicentrarchus labrax) (76 +/- 16 g) were studied in an experimental tank-based flow through system. Performance, stress response and resistance to virus infection were analysed under five stabilized rearing densities: 10, 20, 40, 70 and 100 kg m(-3). Water quality parameters (CO2, total ammonia nitrogen and O-2) were measured and maintained close to the recommended values for farmed sea bass by adjusting water renewal exchange. No significant differences were observed between density treatments, neither on stress response (cortisol) nor susceptibility to nodavirus. With regards to biological performances, the daily feed intake and specific growth rate were significantly lower in fish reared at the 100 kg m(-3) density. Results on the effects of density in sea bass reared in flow through (present study) and in recirculating aquaculture systems (RAS) (Sammouth et al. 2009) were compared as a contribution to the identification of density not affecting health and welfare in farmed sea bass.
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