A method for the quantification and optimization of hydrodynamics in culture tanks
Tóm tắt
A method was developed to quantify hydrodynamic mixing parameters, and to optimize the physical environmental conditions, in culture tanks. Improved mixing will result in better tank water quality, more efficient use of available volume by the culture animals (leading to optimal stocking densities and better feed management) and possibly reduced water pumping requirements. Experiments were conducted to determine the influence of a range of flow rates, residence times, water depths and stocking densities on hydrodynamics in juvenile turbot (Scophthalmus maximus (L.)) tanks. Decreases in water depth resulted in significant improvements in mixing and the efficiency with which the water was used, as indicated by reductions in dead volumes. A depth of less than 9.4 cm at a flow rate of 2 l min−1 was expected to minimize dead volumes in the tank. This indicated that mixing was better in shallower tanks. Within the range 0–13 l min−1, increased flow rate improved mixing at a constant depth of 9 cm (and water volume of 18.54 l) though increased flow rates greater than about 2.5 l min−1 produced only small improvements in mixing. Within the range 0–50 fish per tank (equivalent to a mean stocking density of 0–1.84 kg m−2), stocking density did not significantly influence mixing in tanks with a depth of 9 cm and flow rate of 2 l min−1. Such depth reductions, for demersal species, may be a useful means to either decrease water use without reducing residence time, or alternatively to increase the flushing rate without increasing water use, at a given stocking density. The large changes in the efficiency with which the tanks were used, which were achieved with ease, indicates that attention to water mixing can give positive benefits to a wide range of land-based farm operators. Care must be taken when adjusting tank hydrodynamics, that water quality is maintained and that biological parameters such as stress levels, sunlight effects and feed management are optimal.
Tài liệu tham khảo
Alderson, R. (1979) The effect of ammonia on the growth of juvenile Dover sole (Solea solea) and turbot (Scophthalmus maximus).Aquaculture 17: 291–309.
Bromley, P.J. and Howell, B.R. (1983) Factors influencing the survival and growth of turbot larvae (Scophthalmus maximus L.) during the change from live to compound diets.Aquaculture 31: 31–40.
Burley, R. and Klapsis, A. (1985) Flow distribution studies in fish rearing tanks. Part 2 — Analysis of hydraulic performance of 1 m square tanks.Aquacultural Engineering 4: 113–134.
Burrows, R.E. and Chenoweth, H.H. (1955) Evaluation of 3 types of rearing ponds. U.S. Department of the Interior, Fish and Wildlife Service. Research Report 39, 29 pp.
Burrows, R.E. and Chenoweth, H.H. (1970) The rectangular circulating rearing pond.Progressive Fish-Culturist 32: 67–80.
Cholette, A. and Cloutier, L. (1959) Mixing efficiency determination for continuous flow systems.Canadian Journal of Chemical Engineering 37: 105–112.
Cobb, E. and Titcomb, J. (1930) A circular pond with central outlet for rearing fry and fingerlings of the Salmonidae.Transactions of the American Fisheries Society 60, 121–123.
Colt, J. and Tchobanoglous, G. (1978) Chronic exposure of channel catfishIctalurus punctatus to ammonia: effect on growth and survival.Aquaculture 15: 352–372.
Cripps, S.J. (1990) The design and management of tanks for the culture of turbot (Scophthalmus maximus (L.)). PhD Thesis, Heriot-Watt University, UK, 490 pp.
Cripps, S.J. and Poxton, M.G. (1992) A review of the design and performance of tanks relevant to flatfish culture.Aquacultural Engineering 11: 71–91.
Danckwerts, P.V. (1953) Continuous flow systems: distribution of residence times.Chemical Engineering Science 2: 1–13.
Heap, S.P. and Thorpe, J.P. (1987) A preliminary study of comparative growth rates of 0-group malpigmented and normally pigmented turbotScophthalmus maximus (L.) and turbot-brill hybrids,S. maximus × S. rhombus (L.) at two temperatures.Aquaculture 60: 251–264.
Höner, G., Rosenthal, H. and Krüner, G. (1987) Fluctuations of water quality during the experimental rearing of juvenileSarotherodon galilaeus.Journal of Aquaculture in the Tropics 2: 31–44.
Hughes, J.T., Shleser, R.A. and Tchobanoglous, G. (1974) A rearing tank for lobster larvae and other aquatic species.Progressive Fish-Culturist 36: 129–133.
Klapsis, A. (1983) Investigation of flow and mixing effects in fish rearing tanks. MSc Thesis, Department of Chemical and Process Engineering, Heriot-Watt University, UK. 107 pp.
Lake, N.C.H. (1990) Effects of solar ultraviolet radiation on fish, with particular respect to the culture of turbot and gilthead bream. PhD Thesis, Heriot-Watt University, UK, 443 pp.
Larmoyeux, J., Piper, R. and Chenoweth, H.H. (1973) Evaluation of circular tanks for salmonid production.Progressive Fish-Culturist 35: 121–131.
Levenspiel, O. (1966)Chemical Reaction Engineering (1st edition). J. Wiley and Sons Inc.: London, pp. 242–308.
Poxton, M.G. (1991) A review of water quality for intensive fish culture. In:Aquaculture Europe ′89-Business Joins Science (eds N. De Pauw and R. Billard) European Aquaculture Society Special Publication 12, Bredene, Belgium, pp. 285–-303.
Poxton, M.G. and Allouse, S.B. (1987) Cyclical fluctuations in ammonia and nitrite-nitrogen resulting from the feeding of turbot,Scophthalmus maximus (L.), in recirculation systems.Aquacultural Engineering 6: 301–322.
Purdom, C.E., Jones, A. and Lincoln, R.F. (1972) Cultivation trials with turbot (Scophthaamus maximus).Aquaculture 1: 213–230.
Rosenthal, H., Hoffmann, R., Jörgensen, L., Krüner, G., Peters, G., Schlotfeldt, H.-J. and Schomann, H. (1982) Water management in circular tanks of a commercial intensive culture unit and its effects on water quality and fish condition. ICES Statutory meeting, C.M. 1982/F:22. 13 pp.
Rosenthal, H., Krüner, G., Wiege, U., Höner, G., Meyer, E. and Plümke, E. (1985) Follow-up study on water variations in circular tanks of commercial trout culture units. ICES Statutory meeting, C.M. 1985/F:13. 20pp.
Spectorova, L.V. and Doroshev, S.I. (1976) Experiments on the artificial rearing of Black Sea turbot (Scophthalmus maeoticus maeoticus).Aquaculture 9: 275–286.
Surber, E.W. (1936) Circular rearing pools for trout and bass.Progressive Fish-Culturist 21: 1–14.
Watten, B.J. and Beck, L.T. (1987) Comparative hydraulics of a rectangular cross-flow rearing unit.Aquacultural Engineering 6: 127–140.
Wheaton, F.W. (1977)Aquacultural Engineering. John Wiley and Sons: Chichester, pp. 414–462.
Windholz, M. (1983)The Merck Index (10th edition). Merck and Co. Inc: New Jersey, USA, p. 190.