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1  Aquaculture and Fisheries News / Aquaculture News / Tolerance to, and avoidance of, hypoxia by the penaeid shrimp เมื่อ: เมษายน 30, 2010, 02:49:17 PM
Tolerance to, and avoidance of, hypoxia by the penaeid shrimp (Metapenaeus ensis)

R.S.S. Wu*, P.K.S. Lam, K.L. Wan
Centre for Coastal Pollution and Conservation, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, China

Environmental Pollution 118 (2002) 351–355

Keywords: Penaeid shrimp; Metapenaeus ensis; Hypoxia; Heart beat; Avoidance; Survival

Abstract
Aquatic hypoxia caused by eutrophication may lead to mass mortality of valuable living resources such as fish and shrimp. However, there is little information on the hypoxic tolerance of penaeid shrimp, and whether they are able to avoid hypoxia. In laboratory experiments, LC50, L T50 and heart beats per minute were determined for juvenile Metapenaeus ensis at 0.5, 1.0, 2.0 and 6.0 mg O2 l1. The 8-h LC50 for DO was 0.77 mg O2 l1, while the LT50 at 0.5 mg O2 l1 was 399 min. Heart beat rate
significantly declined when DO fell below 1.0 mg O2 l1. When confronted with a gradient of dissolved oxygen,M. ensis were able to avoid hypoxic areas and move to oxygenated water. M. ensis appeared to be sensitive to hypoxia, and their ability to detect and avoid hypoxia may enhance their survival in habitats where hypoxia may occur. # 2002 Elsevier Science Ltd. All rights  reserved.
2  Aquaculture and Fisheries News / Aquaculture News / Effects of early experience on group behaviour in fish เมื่อ: เมษายน 30, 2010, 02:41:22 PM
Effects of early experience on group behaviour in fish

ANNE G. V. SALVANES*, OLAV MOBERG* & VICTORIA A. BRAITHWAITE†
*Department of Biology, University of Bergen

Keywords: cod; conservation; early experience; enrichment; Gadus morhua; group behaviour; reintroduction; shoaling

Animals that undergo a habitat shift face a number of challenges as they move between habitats; for
example, they may encounter new predator species and may be vulnerable as they adapt to their new
surroundings. An ability to adapt quickly to the new environment is likely to influence post-transition survival, and an understanding of the development of this ability is important in species that we rear for conservation and reintroduction programmes. Juvenile cod, Gadus morhua, undergo a habitat shift during
their development, and they are also a species where reintroduction work has been tried. Here, we describe an experiment that investigated the effects that rearing environment has on cod shoaling behaviour. Cod were tested just after they had undergone the transition from a pelagic to a more benthic existence. We found that cod reared in either an enriched or in a plain, standard hatchery environment differed in terms of their shoaling responses; the shoaling tendency of fish reared in enriched tanks varied between testing environments, but fish reared in plain environments responded in the same way across the testing conditions. We discuss the influence of early experience on the development of appropriate behavioural responses and the importance of this for captive-reared species that are released into the wild.
3  Aquaculture and Fisheries News / Aquaculture News / Determining factors affecting muddy-flavour taint เมื่อ: เมษายน 30, 2010, 02:36:56 PM
Determining factors affecting muddy-flavour taint in farmed barramundi, Lates calcarifer

Steve Percival a, Paul Drabsch b, Brett Glencross c,⁎
a Aquaculture Development and Veterinary Services Pty Ltd (ADVS), 27 Selby Rd, Kettering, TAS 7155, Australia
b Lake Argyle Industries Pty Ltd, PO Box 25, Kununurra, WA 6743, Australia
c Department of Fisheries, Research Division, PO Box 20, North Beach, WA 6920, Australia

Aquaculture 284 (2008) 136–143

Keywords: Asian seabass, Geosmin, 2-methyl-isoborneol, Muddy, Flavour

a b s t r a c t
A series of studies were designed to examine the possible cause and predisposing factors of “muddy” taint in the flesh of barramundi farmed in cages in a freshwater reservoir in Australia. A preliminary flavour
evaluation study confirmed the presence of a muddy-flavour taint issue in the barramundi farmed. This was examined by studying the flavour properties of a series of samples of fish that were freshwater farmed (purged and unpurged), wild (estuarine) and marine-farmed barramundi. No significant differences in flavour attributes and/or acceptability attributes were detected between the wild and farmed barramundi, provided the barramundi was either marine-farmed or purged. However, it was determined that an obvious “muddy” flavour and odour could be detected in the unpurged freshwater origin fish. It was demonstrated that there was a significantly greater muddy-flavour effect in large (~2000 g) compared to small (~400 g) barramundi. It was found that flavour taint was highest in the “belly cut” of the fillet and lower in the “tailcut” and “shoulder” of the fillet and that there is a strong correlation of flavour taint with fat levels in the various fillet cuts. Assessment of the influence of flavour taint in the presence or absence of the compounds geosmin (GSM) and 2-methyl-isoborneol (MIB) identified that at Lake Argyle, in the Kimberley region of northern Australia that it was likely that MIB was the primary compound causing the problem. Assessment of the sensory thresholds for GSM and MIB was constrained by vagaries in the assessment of GSM and MIB from the test water samples. A test based on the serial dilution of depurated and tainted water was undertaken, with barramundi placed within each treatment and subsequently evaluated for their sensory characteristics. A significant increase in the sensory detection of muddy flavour was observed at a level of 60% taint affected water. This corresponded to a water MIB concentration of between 3.5 and 5.5 ng/L.of between 3.5 and 5.5 ng/L.
4  Aquaculture and Fisheries News / Aquaculture News / Swimming behaviour as an indicator เมื่อ: เมษายน 30, 2010, 02:29:18 PM
Swimming behaviour as an indicator of low growth rate and impaired welfare in Atlantic halibut (Hippoglossus hippoglossus L.) reared at three stocking densities

Tore S. Kristiansena,*, Anders Ferno¨ b, Jens Christian Holmc, Lucia Priviteraa, Stine Bakkea, Jan Erik Fosseidengena
a Institute of Marine Research, Austevoll, N-5392 Storebø, Norway
bDepartment Fisheries and Marine Biology, University of Bergen, P.O. Box 7800, N-5020 Bergen, Norway
c Department of Aquaculture, Directorate of Fisheries, Strandgt. 229, Bergen, Norway

Aquaculture 230 (2004) 137–151

Keywords: Swimming behaviour; Low growth rate; Atlantic halibut; Hippoglossus hippoglossus L.


Abstract
The Atlantic halibut (Hippoglossus hippoglossus L.) is a new species in Norwegian aquaculture.
However, in ongrowing trials, halibut shows variable and generally poor rates of growth. The halibut
is a flatfish that spends most of its time resting on the bottom, and it was hypothesized that high
stocking densities with frequent social interactions could lead to behaviour changes, reduced appetite
and impaired welfare. Halibut were kept in six tanks at low, medium, and high densities (18%, 54%
and 112% bottom coverage). All fish were individually tagged with Trovank passive implant
transponder (PIT) tags, allowing an antenna to register fish swimming at the surface. Swimming and
feeding behaviour was also recorded by underwater video cameras. Individual growth rates were
highly variable, but food consumption and growth rates fell significantly with increasing stocking
density, while individual swimming activity rose with increasing density. Frequent ‘‘surface
swimmers’’ had a significantly lower growth rate than fish that were seldom recorded by the PIT
antennae. Surface swimming may therefore be an indicator of suboptimal growth rates and impaired
welfare in reared halibut.
5  Aquaculture and Fisheries News / Aquaculture News / Can fish suffer?: perspectives on sentience, pain, fear and stress เมื่อ: เมษายน 30, 2010, 02:26:41 PM
Can fish suffer?: perspectives on sentience, pain, fear and stress

K.P. Chandroo, I.J.H. Duncan, R.D. Moccia∗

Applied Animal Behaviour Science 86 (2004) 225–250

Keywords: Animal welfare; Aquaculture; Fish; Sentience; Pain; Fear; Stress; Suffering

Abstract
In contrast to other major forms of livestock agriculture, there is a paucity of scientific information
on the welfare of fish raised under intensive aquacultural conditions. This reflects an adherence to the
belief that these animals have not evolved the salient biological characteristics that are hypothesised
to permit sentience. In this review, we evaluate the scientific evidence for the existence of sentience
in fish, and in particular, their ability to experience pain, fear and psychological stress. Teleost fish
are considered to have marked differences in some aspects of brain structure and organization as
compared to tetrapods, yet they simultaneously demonstrate functional similarities and a level of
cognitive development suggestive of sentience. Anatomical, pharmacological and behavioural data
suggest that affective states of pain, fear and stress are likely to be experienced by fish in similar ways
as in tetrapods. This implies that fish have the capacity to suffer, and that welfare consideration for
farmed fish should take these states into account.We suggest that the concept of animal welfare can be
applied legitimately to fish. It is therefore appropriate to recognize and study the welfare of farmed fish.

6  Aquaculture and Fisheries News / Aquaculture News / The impact of stocking density on the welfare of rainbow trout เมื่อ: เมษายน 30, 2010, 02:23:03 PM
The impact of stocking density on the welfare of rainbow trout (Oncorhynchus mykiss)

B.P. North a,⁎, J.F. Turnbull a, T. Ellis b, M.J. Porter c, H. Migaud a, J. Bron a, N.R. Bromage a
a Institute of Aquaculture, University of Stirling, Stirling, Scotland, FK9 4LA, UK
b The Centre for Environment, Fisheries and Aquaculture Science, Weymouth Laboratory, The Nothe, Weymouth, Dorset, UK
c Tasmanian Aquaculture and Fisheries Institute, School of Aquaculture, Tasmania, Australia

Aquaculture 255 (2006) 466–479

Keywords: Welfare assessment; Fin erosion; Cortisol; Lysozyme; Stocking density; Rainbow trout

Abstract
The welfare of farmed fish is a subject of increasing interest and one of the principal areas of concern is stocking density. Thepresent study stocked juvenile rainbow trout in triplicate in 1.82 m3 flow-through tanks at densities of 10, 40, and 80 kg m−3 over a9-month period. Welfare was assessed by measuring a range of population (mortality, growth, size variation, FCR), individualmorphometric (mass, fin condition, condition factor) and physiological (haematocrit, plasma cortisol, lysozyme activity) indicators.
Stocking density did not significantly affect growth or mortality, but the fish held at 10 kg m−3 had a significantly lower mean bodycondition factor and an increased size variation at the end of the study. Stocking density had a significant effect on fin condition,with the 40 and 80 kg m−3 treatments resulting in fish with significantly smaller fins than the 10 kg m−3 treatment. Plasma cortisollevels were greater at 10 kg m−3 on 5 of the monthly sample points. Principal components analysis was used to produce objectivewelfare scores representing coherence that existed between the simultaneously measured individual welfare indicators. The  resulting principal components identified a trend for high levels of cortisol and lower lysozyme activity in the 10 kg m−3. The PCA
also identified a group of fish common to all treatments that had good dorsal and caudal fin scores, but low condition factor. This may have represented individuals that had adopted a non-competitive feeding strategy. The experiment demonstrated that stocking densities of 80 kg m−3 did not produce consistent effects on mean growth rate, or physiological indicators of welfare. Nevertheless,
fin erosion increased with increasing density, although the cause of the erosion remains unclear. The evidence for stronger dominance hierarchies in the 10 kg m−3 treatment, indicate that low as well as high stocking densities have the potential toadversely affect trout welfare.
7  Aquaculture and Fisheries News / Aquaculture News / Physico-chemical and microbiological characteristics เมื่อ: เมษายน 05, 2010, 09:56:19 AM
Physico-chemical and microbiological characteristics of water for fish production using small ponds

Felix W. Ntengwe *, Mojisola O. Edema
The Copperbelt University, School of Technology, Chemical and Environmental Engineering Department, 4662 Jambo Drive, Riverside, P.O. Box 21692, Kitwe, Zambia

Physics and Chemistry of the Earth 33 (2008) 701–707

Keywords: Water-quality, Fish-ponds, Fish-cropping, Bacteria, Correlations

a b s t r a c t
The physical–chemical and biological characteristics of water in fish ponds were investigated with a view
to optimise the conditions for fish productivity using small ponds. Five fish ponds were used in the study.
The water samples were collected in each pond at a depth of 10–15 cm from the surface over a period of
six months and analysed for pH, temperature, DO, alkalinity. The fish activity and growth rates were also
assessed. The results showed that the ponds were slightly acidic to neutral (pH 6.69–7.66). The mean
lowest and highest values of DO were 9.05 and 9.93 mg/L while the values for alkalinity were 67.86
and 90.57 mg/L respectively. The bacterial counts were in the order of 106 and the populations comprised
Pseudomonas, Enterobacter, Salmonella, Staphylococcus, Bacillus, Azotobacter, Arthrobacter species and Escherichia coli. It was also observed that the fish activity increased as the temperature of the water varied from April to September as given by the activity ranges of 55–95, 40–80, 55–80, 70–95 and 55–95/m2 for ponds P1, P2, P3, P4 and P5, respectively. The lowest values were in the months of April, May and June and highest values were in the months of July, August and September. The optimum conditions for increased fish productivity were found to be the warm temperatures (20 < t < 30 C), adequate DO level (>4 mg/L) and appropriate pH (6 < pH < 9) and alkalinity (Alk) (80 < Alk < 200 mg/L). The correlations between characteristics were significant at 0.01 and 0.05 levels (2 tailed). Therefore, the fish productivity can be enhanced if the conditions in the ponds were maintained at optimum levels.
8  Aquaculture and Fisheries News / Aquaculture News / Intensification of pond aquaculture and high ratephotosynthetic systems เมื่อ: เมษายน 05, 2010, 09:53:47 AM
Intensification of pond aquaculture and high ratephotosynthetic systems

D.E. Brune a,*, G. Schwartz a, A.G. Eversole b, J.A. Collier a,
T.E. Schwedler b
a Department of Agricultural and Biological Engineering, Clemson University, Clemson, SC 29634, USA
b Department of Aquaculture, Fisheries and Wildlife, Clemson University, Clemson, SC 29634, USA
Received 15 August 2002; accepted 3 February 2003

Aquacultural Engineering 28 (2003) 65/86

Keywords: Supplemental aeration; Intensification techniques; Partitioned aquaculture systems

Abstract
Aquaculture production systems may range from tanks and raceways, in which water quality is controlled by water dilution and discharge to the environment to captive water systems, in which water quality is controlled by microbial reactions within the tank or pond. Attempts at intensification of pond aquaculture beyond the commonplace practice of supplemental aeration may be classified into categories of physical/chemical techniques and a broad range of microbial techniques. Most of these techniques are directed at raising the ‘ceiling’ of the system ammonia detoxification rate. Physical/chemical techniques for intensification of pond aquaculture have included use of in-pond cages and raceways, water blending and shading of the algal community, as well as, direct flocculation and removal of algal and bacteria biomass from ponds. A variety of microbial processes can be used to reduce ammonia levels in a conventional pond. These processes include nitrification/denitrification, photosynthesis, and heterotrophic bacterial re-growth. In this paper, simplified microbial growth fundamentals, and elemental mass balances are used to analyze and compare the various aquaculture intensification techniques and, in particular, to compare conventional and heterotrophic techniques to the use of high rate photosynthetic systems. Direct or indirect photosynthetic systems include enhanced algal systems (with water mixing), polyculture, hydroponics, wetlands, and terrestrial irrigation/fertilization. The development of Clemson University’s Partitioned Aquaculture System (PAS) constitutes an attempt to combine a
number of the various physical, chemical, and microbial intensification techniques into a single integrated system. The PAS represents an adaptation of high rate microalgal culture to produce a sustainable, minimal discharge, high yield, and more controllable fish production process. The PAS combines the advantages of process control of recirculating tank aquaculture with the lower costs of earthen pond aquaculture. Central to the economic success of the PAS is the use of low speed (1/3 r.p.m.) paddlewheels as an energy efficient means of establishing a uniform water velocity field within an aquaculture pond. The PAS represents a redesign of the conventional aquaculture pond culture technology providing a spectrum of applications ranging from moderate yield (6700/11 200 kg/ha) ‘engineered ecosystems’ to high yield (16 800/33 600 kg/ha) controlled ‘production processes’. This high rate photosynthetic system offers the potential for a 90% reduction in total water usage per
unit of fish produced. The modular nature of the PAS, the increased productivity per unit area, reduced water requirement, and reduced environmental impact offers the potential for fish culture systems to be installed at sites not currently suitable for conventional aquaculture.
9  Aquaculture and Fisheries News / Aquaculture News / Paddlewheel aerator oxygen transfer efficiencies at three salinities เมื่อ: เมษายน 05, 2010, 09:49:05 AM
Paddlewheel aerator oxygen transfer efficiencies at three salinities

Arlo W. Fast a,*, Edmundo C. Tan b, Desmond F. Stevens b,
Jeffrey C. Olson b, Jianguang Qin c, David K. Barclay d
a Hawaii Institute of Marine Biology, Uni6ersity of Hawaii at Manoa, P.O. Box 1056, Kaneohe,
HI 96744, USA
b STO Design Group, Inc., 2500 Redhill A6e., Santa Ana, CA 92705, USA
c School of Biological Sciences, The Flinders Uni6ersity of South Australia, GPO Box 2100,
Adelaide 5001, SA, Australia
d Aquatic Culture and Design, P.O. Box 911, Kapaau, HI 96755, USA

Aquacultural Engineering 19 (1999) 99–103

Keywords: Paddlewheel aerator; Water aeration; Oxygen transfer; Re-aeration

Abstract
Oxygen transfer rates, or standard aeration efficiencies (SAE) were measured using seven
paddlewheel impellers at three salinities (0, 11 and 22‰) and with two aeration devices (0.37 and 0.75 kW) in clean water tests. Oxygen transfer rates increased significantly at higher salinities. With the 0.37-kW aerator, mean SAE values increased 67% at 11‰ compared with freshwater (0‰), while SAE increased 46% at 11‰ with the 0.75-kW aerator. SAE values increased further at 22‰, but the increases were much less. These findings clearly demonstrated a significant salinity affect on oxygen transfer efficiencies with paddlewheel aerators.
10  Aquaculture and Fisheries News / Aquaculture News / Oxygenation and carbon dioxide control in water reuse systems เมื่อ: เมษายน 05, 2010, 09:47:17 AM
Oxygenation and carbon dioxide control in water reuse systems

S.T. Summerfelt a,*, B.J. Vinci b, R.H. Piedrahita c
a Conser6ation Fund Freshwater Institute, P.O. Box 1889, Shepherdstown, WV 25443, USA
b Agricultural and Biological Engineering Department, Cornell Uni6ersity, Ithaca,
NY 14853 -5701, USA
c Biological and Agricultural Engineering Department, Uni6ersity of California, Da6is,

Aquacultural Engineering 22 (2000) 87–108

Keywords: Water reuse systems; Dissolved oxygen control; Dissolved carbon dioxide control


Abstract
Control of dissolved gases, especially oxygen and carbon dioxide, is an essential component of intensive water reuse systems. Control of both dissolved oxygen and carbon dioxide concentrations is typically carried out by means of gas transfer processes, although chemical processes are also used to control carbon dioxide concentration. Theoretical and practical considerations of oxygenation and carbon dioxide removal are reviewed in this paper. The theory of gas transfer is presented in general terms, followed by a more detailed description of the basis for a new calculation procedure for carbon dioxide degassing processes. Equipment used for oxygen injection is described, and a new method for estimating packed
column degassing parameters is introduced.
11  Aquaculture and Fisheries News / Aquaculture News / Prediction of aeration performance of paddle wheel aerators เมื่อ: เมษายน 05, 2010, 09:45:15 AM
Prediction of aeration performance of paddle wheel aerators

Sanjib Moulick, B.C. Mal *, S. Bandyopadhyay
Aquacultural Engineering Section, Agricultural and Food Engineering Department, IIT, Kharagpur 721 302, West Bengal, India

Aquacultural Engineering 25 (2002) 217–237

Keywords: Paddle wheel aerator; Similarity criteria; Dimensionless numbers; Aeration performance

Abstract
Aeration experiments were conducted in brick masonry rectangular tanks of dimensions 2.9&times;2.9&times;1.6 and 5.9&times;2.9&times;1.6 m to study the effect of geometric and dynamic variables on aeration process based on dimension analysis. Non-dimensional numbers relating to standard aeration efficiency (SAE), effective power (P) and theoretical power per unit volume (P/V) termed as SAE, Ne and X, respectively, are proposed. An optimal geometric similarity of various linear dimensions was established. It has been established that neither the Reynolds criterion nor the Froude criterion is singularly valid to simulate either SAE or Ne, simultaneously for different sizes of aerators, even though they are geometrically similar. Occurrence of scale effects due to the Reynolds and the Froude laws of similitude on both SAE and Ne are also evaluated. Simulation equations uniquely correlating SAE, Ne and X were developed which can predict the aeration performance of paddle wheel aerators having the optimised geometric dimensions as established.
12  Aquaculture and Fisheries News / Aquaculture News / Effect of speed on Taiwanese paddlewheel aeration เมื่อ: เมษายน 05, 2010, 09:41:45 AM
Effect of speed on Taiwanese paddlewheel aeration

Eric L. Peterson *, Margaret B. Walker
School of Engineering, James Cook Uniersity, Townsille 4811, Australia

Aquacultural Engineering 26 (2002) 129–147

Keywords: Aeration; Paddlewheel; Oxygen transfer; Energy conservation

Abstract
Aerators are generally used in Australian aquaculture ponds day and night at full speed without regulation. This situation is untenable in view of climate change, as energy conservation becomes an essential issue for all industries, including aquaculture. Variable speed performance curves were developed for the paddlewheel aerators that have been employed on Australian marine aquaculture ponds so that speed may be actively adjusted to match pond water quality requirements. Results show that speed of rotation is a significant factor effecting the performance of a paddlewheel aerator. Of particular note was the observation of backsplashing when kinetic energy (pumping head) was greater than the
radius of a paddlewheel. The process of backsplashing is readily identified when whitewater
is seen flying above a paddlewheel. It is hypothesised that backsplashing dilutes the oxygen-starved water entering a paddlewheel, thereby degrading the operational efficiency. Backsplash breakpoint speed is related to paddlewheel diameter. Aerator users can reduce backsplash by changing mechanical gearboxes or using a variable frequency drive (VFD inverter).
13  Aquaculture and Fisheries News / Aquaculture News / 2-D hydrodynamic model simulating paddlewheel-driven circulation เมื่อ: เมษายน 05, 2010, 09:38:37 AM
2-D hydrodynamic model simulating paddlewheel-driven circulation in rectangular shrimp culture ponds

Yun Ho Kanga,*, Moon Ock Leeb, Sang Duk Choic, Yong-Sik Sind
a Aquaculture Research Center, Yosu National University, Yeosu 550-749, South Korea
b Division of Ocean System, Yosu National University, Yeosu 550-749, South Korea
c Division of Aqualife Science, Yosu National University, Yeosu 550-749, South Korea
dDepartment of Marine Environmental Engineering, Mokpo National Maritime University,

Aquaculture 231 (2004) 163–179

Keywords: Paddlewheel; Pond circulation; Numerical model; Mass correction factor

Abstract
This study surveyed and simulated paddlewheel-driven circulation in rectangular shrimp culture
ponds. Paddlewheels are widely used for highly intensive culture ponds to improve reaeration and
circulation. From flow measurements, the major circulation pattern was found to be a single large
eddy with strong and weak flows, respectively, along the pond bank and the eddy centre. A twodimensional depth integrated numerical model was refined to represent the circulation, with
acceleration of the paddlewheel given as a shaft force divided by the water mass driven away by
paddlewheel blades. The model was applied to a pond F, deploying a single paddlewheel and calibrated for a mass correction factor a in the range 15–20 and for a dimensionless eddy viscosity constant c of 6. The model was then applied to two ponds A and B, with four paddlewheels deployed at four corners, respectively. The measured and predicted currents were processed using regression analysis to show both the correlation coefficients and gradients; i.e. 0.9067, 1.0393 for direction and 0.6691, 0.8307 for speed in pond A and 0.8269, 1.0075 for direction and 0.7138, 0.9362 for speed in pond B. It was concluded from these results that the model could deal with the paddlewheel-driven jet flow in a simple way to that of using a mass correction factor a, first shown in this study and giving good prediction. Therefore, the model provides a useful tool to predict horizontal circulation and an insight into the circulation-related sedimentation and water quality in shrimp ponds.
14  Aquaculture and Fisheries News / Aquaculture News / Design of high efficiency surface aerators Part 3 เมื่อ: เมษายน 05, 2010, 09:35:14 AM
Design of high efficiency surface aerators Part 3. Dimensional analysis of rotor performance

Beatriz Cancino∗
Department of Food Engineering, Universidad Cat&oacute;lica de Valpara&acute;ıso, Waddington 716, Valpara&acute;ıso, Chile

Aquacultural Engineering 31 (2004) 117–121

Keywords: Surface aerator design; Surface aerator efficiency

Abstract
This paper is the third and final part of this work. The first two parts studied the mass transfer
equations for oxygen in water and presented equations to design propeller of the surface aerator based
on its similitude to an axial flow pump. Additionally, the results of aeration test with 23 different rotor
setups were presented, in which the highest SAE = 1.805 kg O2/kWh, was for the rotor designed
with the axial flow pump criteria. The aim of this part is to describe the aerator’s behavior as a general equation, using dimensional analysis. These equations are defined in terms of geometric characteristics and aeration efficiency (oxygen transfer rate/input power). It can be concluded that the aeration efficiency improves with the Froude number, but is inversely related to the speed and
diameter of the propeller.
15  Aquaculture and Fisheries News / Aquaculture News / Design of high efficiency surface aerators เมื่อ: เมษายน 05, 2010, 09:32:13 AM
Design of high efficiency surface aerators Part 2. Rating of surface aerator rotors

Beatriz Cancino∗
Department of Food Engineering, Universidad Cat&oacute;lica de Valpara&acute;ıso, Waddington 716, Valpara&acute;ıso, Chile

Aquacultural Engineering 31 (2004) 99–115

Keywords: Surface aerator design; Surface aerator efficiency

Abstract
This paper is the second part of a three partwork about surface aerator design for aquaculture. In this
work, the rotors for oxygen mass transfer developed in the first part were tested. Tests were conducted
on 23 different rotor configurations defined by the type of propeller, the inlet and exit angles of the
blades and the percentage of immersion. The “Kinetic 3” propeller—designed using the criteria of an
axial flow pump with a diameter of 94 mm, an inlet angle of 11◦ and an exit angle of 25◦—yielded
the highest aeration efficiency at 10 ◦C: 1.769 kgO2/kWh (SAE = 1.805 kgO2/kWh). The Conrad
propeller—designed using other criteria—with a diameter of 104 mm, an inlet angle of 25◦ and an
exit angle of 12◦, yielded the highest value for the global mass transfer coefficient at 10 ◦C: 3.249 h−1.
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