Aquacultural Engineering (AQUACULT ENG )

Publisher: Elsevier

Description

Aquacultural Engineering is concerned with the design and development of effective aquacultural systems for marine and freshwater facilities. The journal aims to apply the knowledge gained from basic research which potentially can be translated into commercial operations. Problems of scale-up and application of research data involve many parameters, both physical and biological, making it difficult to anticipate the interaction between the unit processes and the cultured animals. Aquacultural Engineering aims to develop this bioengineering interface for aquaculture and welcomes contributions in the following areas: - engineering and design of aquaculture facilities - engineering-based research studies - construction experience and techniques - in-service experience, commissioning, operation - materials selection and their uses - quantification of biological data and constraints Style of presentation is flexible, but those papers dealing with specific problems should attempt to define them clearly in terms of systems engineering, quantifying the constraints, proposing solutions, implementing and detailing the design, and finally evaluating the outcome.

  • Impact factor
    1.41
    Hide impact factor history
     
    Impact factor
  • 5-year impact
    1.67
  • Cited half-life
    8.40
  • Immediacy index
    0.23
  • Eigenfactor
    0.00
  • Article influence
    0.39
  • Website
    Aquacultural Engineering website
  • Other titles
    Aquacultural engineering (Online)
  • ISSN
    0144-8609
  • OCLC
    38524840
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

Elsevier

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Pre-print allowed on any website or open access repository
    • Voluntary deposit by author of authors post-print allowed on authors' personal website, arXiv.org or institutions open scholarly website including Institutional Repository, without embargo, where there is not a policy or mandate
    • Deposit due to Funding Body, Institutional and Governmental policy or mandate only allowed where separate agreement between repository and the publisher exists.
    • Permitted deposit due to Funding Body, Institutional and Governmental policy or mandate, may be required to comply with embargo periods of 12 months to 48 months .
    • Set statement to accompany deposit
    • Published source must be acknowledged
    • Must link to journal home page or articles' DOI
    • Publisher's version/PDF cannot be used
    • Articles in some journals can be made Open Access on payment of additional charge
    • NIH Authors articles will be submitted to PubMed Central after 12 months
    • Publisher last contacted on 18/10/2013
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Accepted manuscript (unedited version) available online: 24-DEC-2014 http://dx.doi.org/10.1016/j.aquaeng.2014.11.005
    Aquacultural Engineering 12/2014; TBC(TBC):TBC.
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    ABSTRACT: In sole (Solea spp.) culture, like in other flatfish culture, it's likely that a vertical gradient of dissolved oxygen (DO) occurs with the lower concentrations being at the tank bottom. This lower concentration at the tank bottom is a consequence of fish oxygen consumption and of the presence of the boundary layer. This fact generates lower DO concentrations in the near-bottom zone where soles are lying most of the time. The aim of this work was to study the hydrodynamic conditions that determine the oxygen gradient that occurs in the layer of water adjacent to flatfish. Three flow rates were tested in a circular tank and in a rectangular or raceway tank. For each flow rate, water velocities, boundary layer thickness and Reynolds number were calculated. Results showed that the vertical gradient of dissolved oxygen diminishes when water velocity and Reynolds numbers (Re) increase. At the fish density used in this work (11.6 kg m−2), when Re decreased under 6000, a large increase in the DO gradient was observed. Guidelines are presented to determine in which situations, as defined by hydraulic parameters, Re > 6000 is achieved and DO stratification avoided. The present work shows that in raceways, the flow rate required to avoid DO stratification is higher than that typically needed to maintain water quality (oxygen, ammonia-nitrogen, carbon dioxide and suspended solids). In circular tanks, it can be easier to achieve velocities that are high enough to avoid stratification with low water inlet flow rates, by adjusting the area of the water entry orifices.
    Aquacultural Engineering 12/2014;
  • Aquacultural Engineering 10/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: A step towards environmental sustainability of recirculated aquaculture systems (RAS) is implementation of single-sludge denitrification, a process eliminating nitrate from the aqueous environment while reducing the organic matter discharge simultaneously. Two 1700 L pilot-scale RAS systems each with a 85 L denitrification (DN) reactor treating discharged water and hydrolyzed solid waste were setup to test the kinetics of nitrate and COD removal. Nitrate removal and COD reduction efficiency was measured at two different DN-reactor sludge ages (high θX: 33–42 days and low θX: 17 - 23 days). Nitrate and total N (NO3− + NO2− + NH4+) removal of the treated effluent water ranged from 73–99% and 60 - 95% during the periods, respectively, corresponding to an overall maximum RAS nitrate removal of approximately 75%. The specific nitrate removal rate increased from 17 to 23 mg NO3−-N·(g TVS·d)−1 and the maximal potential DN rate (measured at laboratory ideal conditions) increased correspondingly from 64–68 mg NO3−-N·(g TVS·d)−1 to 247–294 mg NO3−-N·(g TVS·d)−1 at high and low θX, respectively. Quantification of denitrifiers in the DN-reactors by qPCR showed only minor differences upon the altered sludge removal practice. The hydrolysis unit improved the biodegradability of the solid waste by increasing volatile fatty acid COD content 74–76%. COD reductions in the DN-reactors were 64–70%. In conclusion, this study showed that single-sludge denitrification was a feasible way to reduce nitrate discharge from RAS, and higher DN rates were induced at lower sludge age/increased sludge removal regime. Improved control and optimization of reactor DN-activity may be achieved by further modifying reactor design and management scheme as indicated by the variation in and between the two DN-reactors.
    Aquacultural Engineering 09/2014;
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    ABSTRACT: For many decades, the traditional polyculture systems have contributed to increasing productivity throughout the Taiwan regions. It has been recognized that arsenic (As)-contaminated groundwater used for aquaculture in the southwestern coastal region of Taiwan is likely to pose a health threat to fish and humans. The purpose of this study was to assess farmed milkfish and tilapia exposure risk to As in a polyculture system using a model-based risk assessment framework. A first-order three-compartment model was used to simulate arsenic accumulation in fish and sediment appraised with the field-observed data. We constructed dose–response profiles obtained from acute toxicity bioassays to assess milkfish and tilapia exposure risk during different growing seasons. A probabilistic risk model was used to estimate the potential exposure risk. We showed that As accumulations in milkfish and tilapia were higher in summer than in fall. We found that there was a 20% probability for milkfish exceeding ∼2% mortality in summer. However, waterborne As is not likely to pose a mortality risk for tilapia. Our results also revealed that tilapia benefited milkfish by reducing As concentrations in the water, indicating that tilapia can be biocontrol agents in the milkfish–tilapia polyculture systems. We suggest that the present mechanistic assessment framework can be used to assess exposure risk to environmental pollutants in polyculture systems and provide an appropriate exposure analysis to improve decision-making in the design and development of effective aquaculture systems.
    Aquacultural Engineering 09/2014; 62:1–8.
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    ABSTRACT: Underwater anti-maturation-lights have recently been exploited to position sea-caged Atlantic salmon (Salmo salar L.) deeper at night in an effort to reduce infections by salmon lice (Lepeophtheirus salmonis) in surface layers. However, anti-maturation-light use is impermanent because lighting during decreasing day-lengths stimulates sexual maturation which is detrimental for fish welfare, growth and meat quality. The effects from lights on maturation are related to both light intensity and light spectrum. Here, we explored caged salmon depth use in response to lights of four low intensities (0.01, 0.10, 1.0 and 10.0 μE as measured 1 m from the lamps) and seven different colours (broadband white LED lamp and narrow spectrum violet, blue, green, yellow, red and deep red LED lamps). Triplicate sea cages (12 × 12 m and 11 m deep) holding approximately 5000 fish of 1.5 kg were exposed to each light positioned at 10 m depth for one night. Echo sounders registered fish vertical positioning on nights of light treatments and no light (control nights) before and after each light exposure. Results showed that submerged lights generally caused fish to maintain their day-time swimming depth near 10 m (light depth) during the night, as opposed to the typical migration of salmon to upper cage depths at dusk observed on control nights. Quantities of fish staying deep decreased with lowered light intensity, but even 0.1 μE had effects. All light colours, except deep red, significantly affected swimming depth, with a trend of increased effect at lower wavelength colours. Temperature stratification strengthened light effects when warmer water was near the lamps and weakened effects in the case of warmer water near the surface. This study opens up the potential of using low intensity lights at decreasing day-lengths that may not affect sexual maturation and remain suitable for guiding salmon away from surface waters rich in lice infective stages
    Aquacultural Engineering 09/2014;
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    ABSTRACT: The positive effects of a blue gravel substrate as a means of environmental enrichment have been previously observed for gilthead seabream Sparus aurata. The aim of the present study was to investigate whether the blue color per se is efficient to produce similar benefits to those observed with the blue substrate. If this hypothesis proves true, then it would be more practical just to paint the bottom of the rearing tanks to this specific color. Triplicated tanks contained the Blue Substrate (BS), the Photo of the Blue Substrate (PBS) or remained plain - Control (C). Fish groups of 18 specimens (mean initial body mass 20.2 ± 0.26 g) were reared in these conditions for 75 days in a recirculating aquaculture system (RAS). According to results, BS fish showed greater final body mass and less aggression than PBS and C fish indicating that the presence of the blue substrate and not its blue color is responsible for the beneficial effects of the blue substrate. In the case of several growth parameters (i.e. specific growth rate, food conversion ratio, total and standard length), the lack of significant difference between BS and PBS fish suggests that the substrate color has also merit. In conclusion, present results confirm that the use of the blue substrate on the tank bottom improves gilthead seabream welfare and provides for growth benefits. It is also shown that it is not enough just to paint the tank bottom in this certain color. The effectiveness of this environmental enrichment, ensuring gilthead seabream welfare, strengthens the use of land-based aquaculture facilities and the reassessment of RAS inclusion in existing legislation concerning organic aquaculture for on-growing production stage.
    Aquacultural Engineering 09/2014;
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    ABSTRACT: Little information is available on steroid concentrations in the rearing water of aquaculture systems and whether they accumulate in recirculating aquaculture systems (RAS). Therefore this study aimed at determining (1) the concentrations and variation of cortisol and sex steroids in RAS, (2) the contribution of fish rearing conditions to steroid concentrations in seven commercial RAS. Each RAS was sampled twice at three different points: (1) make-up water; (2) influent and (3) effluent of the rearing unit. The results showed significant higher steroid concentrations in the influent and effluent when compared with the make-up water. On average cortisol concentration was 15.7% higher in the effluent when compared with the influent. Mean steroid concentrations in the rearing unit effluent varied between: 3.8–217.0 ng/L for cortisol, 3–12.5 ng/L for testosterone, 0.9–7.1 ng/L for 11-ketoteststerone and 1.8–12.8 ng/L for 17,20β-dihydroxypregn-4-en-3-one. Stocking density, Total Ammonia-Nitrogen concentration and orthophosphate-P concentration (a measure of make-up water usage) showed a positive correlation with sex steroids in the water. The steroid concentrations from the present study were orders of magnitude lower than initial estimations indicating a water treatment efficiency of >99%. The results suggest that an intensification of fish production through decrease of make-up water use and increase of stocking density will lead to a build-up of steroids in the water. Although intensification is critical for the economical success of RAS, this ultimately could affect fish performance as steroids accumulates in the water of RAS at levels that can potentially be detected by some fish species.
    Aquacultural Engineering 09/2014; 62:9–16.
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    ABSTRACT: The carrying capacity for aquaculture cage farming in Spencer Gulf (South Australia) is based in part on guidelines that the maximum feed rates and nutrient flux into the lease regions are determined such that the maximum nutrient concentration c does not exceed a prescribed value (say cP) to ensure ecosystem health – ecological carrying capacity. The goal of this study is to allow the rapid estimation of maximum nutrient fluxes and feed rates at new lease sites. Spencer Gulf is chosen as a case study although the methodology should find application in other regions around the world. In part I of this study, semi-analytic solutions were obtained to show that to a good approximation the maximum nutrient flux (feed rate) F can be simply estimated from: F = cP/T* where T* is a flushing time scale of the cage or lease region. In this study a 3-dimensional hydrodynamic model for Spencer Gulf is used to determine the parameters needed to estimate T* and thus F and feed rates at every model cell in the gulf. The parameters needed include the vector mean speed (U), r.m.s. tidal amplitude (UK) and the mean shear dispersion diffusivity (KS). As a case study, these parameters and T*, are estimated by three-monthly, winter averages. Results show the vector mean speed to be very small (U ∼ 0.01 m/s), tidal velocities large (UK ∼ 0.3–1 m/s) and the associated shear dispersion coefficients very large (KS ∼ 10–100 m2/s). Flushing at the scale of the lease (600 m) and in the upper gulf is generally dominated by diffusive affects for which the maximum nutrient flux (and feed rates) is largest. The results should find application in other finite source flux problems in the coastal oceans including desalination plants and ocean outfalls.
    Aquacultural Engineering 09/2014; 62:66–78.
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    ABSTRACT: The separation performance of a low-pressure hydrocyclone was tested using fine organic particles from 1 to 700 μm. The dimensions of the low-pressure hydrocyclone were an inflow diameter of 30 mm, a cylinder length of 575 mm, an overflow diameter of 60 mm, an underflow diameter of 50 mm, a cylinder diameter of 335 mm and a cone angle of 68°. The low-pressure hydrocyclone was operated with a lower inlet pressure (average 1.38–5.56 kPa) that could be maintained under water level differences that ranged from 17.5 to 53.5 cm between the water surface of the feeding mass cylinder and the middle of the inlet pipe of the low-pressure hydrocyclone. By varying the inflow rate, underflow ratio and feed concentration, the separation performance of the low-pressure hydrocyclone was affected. The separation performances were determined from total separation efficiency and grade efficiency. Separation performances were determined according to the different inflow rates of 400, 600, 800 and 1000 ml s−1 and their respective underflow ratios that ranged from 5% to 30%. The maximum total separation efficiencies for each inflow rate were 41%, 46% and 46% at 400, 800 and 1000 ml s−1 inflow rates, respectively, and at underflow rates of 30% of the inflow rates. In addition, a total separation efficiency of 46% was employed at 600 ml s−1 of inflow rate and with an underflow rate of 25% its inflow rate. As the feed concentration increased from 25 to 150 mg l−1, the separation performances were gradually decreased. For the fine particles ranging 1–200 μm, the grade efficiency was higher at the higher inflow rate (higher than 600 ml s−1) and higher underflow rate. However, for the coarse particles ranging 400–700 μm, the grade efficiency was higher at the lower inflow rate (lower than 600 ml s−1) and higher underflow rate. The cut-point (d50) values ranged from 30 to 200 μm for a feed size range of 1–700 μm. The Response Surface Method (RSM) model predicted an optimum operating inflow rate and underflow ratio of 721 ml s−1 of inflow rate and 30%, respectively, for the low-pressure hydrocyclone at a maximum total separation efficiency. Based on these findings, further design and operating adaptation of low-pressure hydrocyclones used for fine solids removal in recirculating aquaculture systems is expected.
    Aquacultural Engineering 08/2014;
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    ABSTRACT: While performing in situ water quality remediation of aquaculture water using sediment microbial fuel cell, the present study provides effect of operating pH, distance between electrodes, and external resistance on organic matter and nitrogen removal as well as on power generation. Chemical oxygen demand (COD) removal was observed to be directly proportional to the distance between electrodes and inversely proportional to the influent pH as well as external resistance. However, total nitrogen (TN) removal increased with increase in pH and distance between electrodes; whereas it decreased with increase in external resistance. Power production reduced with decrease in pH, but increased with decrease in external resistance and distance between electrodes. Two factor and three factor interactions were observed to be less significant for COD, TN removal and power density. From the statistical correlation among these parameters, feed pH of 7.6-8.5, distance between electrode of 90-100 cm and external resistance of 0-52 Ω were found to be optimum for achieving optimal COD removal, TN removal and power density. Validation of model predictions for treatment of aquaculture water conceded that the SMFC exhibited acceptable COD and TN removal efficiencies which in turn facilitate its use for in situ aquaculture water remediation effectively.
    Aquacultural Engineering 07/2014;
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    ABSTRACT: The polyculture of frogs and tilapia was evaluated in twelve pens made of polypropylene, installed within cages linearly distributed in a pond. 43 bullfrogs (Lithobates catesbeianus) with 79.1 ± 16.9 g were distributed in each pen; and 30 tilapia fry (Oreochromis niloticus) with 17.0 ± 1.0 g were distributed in each cage. Three feeding frequencies were tested (24, 48 and 96 meals/day) and the feed was supplied by automatic feeders. Tilapia were fed only with the leftovers because the feed was supplied just to the frogs. At the end of the experiment (120 days), the average values of the apparent feed conversion ratio (FCR) of the frogs were 2.46, 2.43 and 2.11 for the feeding frequencies of 24, 48 and 96 meals/day, respectively; regarding the polyculture, frogs and tilapia together, these values were 1.55, 1.52 and 1.33 for the same frequencies, respectively. The results indicated that the use of high feeding frequency (96 meals/day) improved FCR of frogs’ production with consequent reduction of feed waste. The polyculture showed that it is possible to produce frogs in cages sustainably.
    Aquacultural Engineering 07/2014;
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    ABSTRACT: In this work two inorganic coagulants, FeCl3 and polymeric aluminum sulfate (PAS) were tested for treating backwash waters from a drumfilter of a brackish RAS with a salinity level of 17.0 g/L. Their performances in terms of removal of total suspended solids (TSS), turbidity, total organic carbon (TOC), total phosphorus (TP) and reactive phosphorus (RP) were investigated. The results show that the removal efficiencies of total suspended solids (TSS), turbidity, total phosphorus (TP) and reactive phosphorus (RP) at the brackish conditions are higher than these in fresh condition with the same dosage of FeCl3 reported in literature. Moreover, dosing PAS caused a 9% decrease in biochemical oxygen demand (BOD5) of backwash waters, compared to that of the control group without adding PAS. The effects of FeCl3 and PAS as well as the effect of compatible solutes on biomethane potential (BMP) of the sludge from the RAS were examined. The results of BMP tests show that addition of glycine betaine (GB) 0.50 g/L, trehalose (T) 0.50 g/L and the combination 0.25 gGB/L plus 0.25 gT/L enhanced BMP of the sludge by 9.0%, 11.6% and 10.3%, respectively, compared with that of the control group without addition of compatible solutes. However, inorganic coagulants, FeCl3 and PAS, reduced BMP of the sludges from the sieve of the brackish RAS by 5.3% and 15.1%, respectively. Particularly, PAS (2.4 gAl/L) significantly lessened BMP. Therefore, PAS may not be a proper coagulant for concentrating sludges if anaerobic digestion is going to be adopted as a sludge post treatment approach to achieve sludge reduction and energy recovery. However, FeCl3 may be a potential coagulant to further coagulate and flocculate backwash waters from marine RAS without substantially affecting the anaerobic digestibility of sludge produced by addition of FeCl3.
    Aquacultural Engineering 07/2014;