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1.
Studies were conducted to characterize raceway water quality, effluent water quality, and waste solids within three, raceway-type trout farms. No significant differences were found in effluent water quality between the three farms during 7 months of monitoring. Average effluent quality over the course of the day was not found to be impaired. However, effluent quality was found to change significantly during times of feeding and harvesting. In a concrete/earthen-lined farm, normalized total suspended solids (TSS) concentrations were as high as 115 and 63 mg/l during harvesting and feeding events, respectively. Total Kjeldahl nitrogen (TKN) and ortho-phosphate (OP) also increased with higher TSS loads. The majority of particles (by weight) measured in effluent samples at all three farms were evenly divided between the smallest range (1.5–30 μm) and the largest (>210 μm). For settled sludge samples, the majority of the particles were in the size range of 1.5–30 μm. Particle size in the raceway was positively correlated with fish size during feeding events, but this correlation dissipated during the 4-h period after feeding. The accumulation and characteristics of sludge in a sediment trap were also monitored over a 22-day period.  相似文献   

2.
A propeller-wash bead filter (PWBF) and a fluidized sand filter (FSF) on a 28 m3 recirculating system stocked with tilapia maintained favorable water quality at five different feed rates, ranging from 0.9 to 4.5 kg feed per day. TAN removal rates ranged up to about 200 g TAN/m3 of media per day for each of the units. Peak rates of 244 g TAN/m3 of media per day were observed when the recirculating flow was boosted by 20%. Roughly 75% of the removal was accomplished by the fluidized sand filter an observation that is consistent with the difference between the fluidized sand filter volume (0.92 m3) and the bead filter media volume (0.28 m3). The bead filter's primary function was clarification. At the highest daily feed load, over 570 g dry weight of solids were removed during each daily bead filter backwashing event. A 20% increase in flow, at the same daily feed rate, improved solids removal to over 670 g dry weight per bead filter backwash event. The PWBF and FSF combination provided suitable water quality for fish production; however, further increases in feed loading were limited by carbon dioxide buildup and oxygen limitations.  相似文献   

3.
Sediment removal capacity is assessed for a constructed mangrove wetland, and a non-vegetated settling pond that are both used for filtering water in tropical aquaculture. The assessment is performed through sediment budget analysis using data of suspended sediment concentration collected from optical backscatter sensors. The sensors were deployed at the pond's inlet and outlet. These data sets provide a measure of trapping efficiency of each pond with different flow regimes and settling areas. The tides influenced flow in the wetland but none was felt in the settling pond. The average trapping efficiency obtained for the vegetated and the non-vegetated ponds was (40±33) and (70±36)%, respectively. The deposition rate calculated for the vegetated and non-vegetated pond ranges between 13–174 g/m2 per h (average=63 g/m2 per h) and 10–19 g/m2 per h (average=14 g/m2 per h), respectively. The efficiency of vegetated and non-vegetated ponds is likely to be improved by decreasing the aspect ratio (length/width) from the current value of 6 to 1 and of 5 to 1, respectively.  相似文献   

4.
The design and operation of aquaculture tanks should minimize stagnant areas especially in the immediate vicinity of the fish. In tanks with pelagic fish, mixing caused by the water flow and by fish swimming is sufficient to maintain dissolved oxygen and metabolite concentrations in the immediate vicinity of the fish that are similar to those in the main water body. Given the behavior of sedentary benthic species, such as the California halibut (Paralichthys californicus), and their tendency to remain motionless on the bottom of aquaculture tanks, often in layers that are several fish deep, water quality may stratify with the worse conditions occurring in the area where they fish are lying. The purpose of this study was to evaluate the influence that California halibut (450 g average weight) may have on the vertical profile of oxygen concentration in a raceway (239 cm long, 28 cm wide) and a circular tank (92 cm diameter) operated at two water depths (10 and 20 cm). Oxygen was measured at each centimeter of the vertical profile both in an area with fish and without fish to assess their influence.

Results showed a lower oxygen concentration in the near-bottom region of the raceway and circular tanks. The phenomenon was most pronounced in the raceway operated at a 20 cm depth, but was also observed in the circular tank operated at 20 cm and in the raceway at 10 cm.

Measurements were also taken in samples collected just in front of or directly from a fish's mouth. A zone of depressed oxygen concentration in the immediate vicinity of the fish was documented, with oxygen concentrations as low as 50% of the measured tank effluent concentration. The magnitude of the depression was greater in raceways than in circular tanks and in 20 cm water depth than in 10 cm depth. The fish remained sedentary in these zones of depressed oxygen concentration for extended periods of time and frequently exhibited hyperventilation. The oxygen concentrations in the vicinity of the fish were consistently lower than the concentrations measured in the tank effluent. Therefore, effluent measurements did not provide an accurate representation of conditions to which the fish were exposed.  相似文献   


5.
This research reveals the applied engineering basis for determining the particle size and settling velocity distributions of solids generated while rearing wild-caught premature punctuated snake-eels (Ophichthus remiger) in a prototype recirculating aquacultural system. Settled solids were sampled from the bottom of the rearing tanks, and suspended solids were sampled before filtration within the drum filter and analyzed to characterize their settling velocity and particle size properties. These particle properties are considered bioengineering parameters since they will provide biological information to improve engineering solutions for RAS solids removal processes. The average settling velocity for the settleable solids in the rearing tanks was 2.89 ± 0.02 cm s−1, and the average particle size ranged between 7.32 ± 3.41 and 19.44 ± 8.58 mm. Suspended solids within the drum filters before filtration had an average settling velocity of 0.35 ± 0.11 cm s−1 and it was found that 69.93 % of the particles size was greater than 200 μm, 15.40 % were within the range of 120 μm and 90 μm sizes, and 6.53 % were between 70 μm and 40 μm sizes. The particle physical properties, settling curves, and particle sizes curves obtained from this experience represent valuable information to be used to improve engineering design of solids handling mechanisms, especially in marine land-based systems, and in this case, applied for rearing wild-caught punctuated snake-eels. The present investigation constitutes an advance in the knowledge of applied engineering to the design of a marine aquaculture fattening operation targeted to feed up wild-caught premature punctuated snake-eels to the point of sale or trade.  相似文献   

6.
A partial-reuse system for coldwater aquaculture   总被引：7，自引：0，他引：7  
A model partial-reuse system is described that provides an alternative to salmonid production in serial-reuse raceway systems and has potential application in other fish-culture situations. The partial-reuse system contained three 10 m3 circular ‘Cornell-type’ dual-drain culture tanks. The side-wall discharge from the culture tanks was treated across a microscreen drum filter, then the water was pumped to the head of the system where dissolved carbon dioxide (CO2) stripping and pure oxygen (O2) supplementation took place before the water returned to the culture tanks. Dilution with make-up water controlled accumulations of total ammonia nitrogen (TAN). An automatic pH control system that modulated the stripping column fan ‘on’ and ‘off’ was used to limit the fractions of CO2 and unionized ammonia nitrogen (NH3---N). The partial-reuse system was evaluated during the culture of eight separate cohorts of advanced fingerlings, i.e., Arctic char, rainbow trout, and an all female brook trout × Arctic char hybrid. The fish performed well, even under intensive conditions, which were indicated by dissolved O2 consumption across the culture tank that went as high as 13 mg/L and fish-culture densities that were often between 100 and 148 kg/m3. Over all cohorts, feed conversion rates ranged from 1.0 to 1.3, specific growth rates (SGR) ranged from 1.32 to 2.45% body weight per day, and thermal growth coefficients ranged from 0.00132 to 0.00218. The partial-reuse system maintained safe water quality in all cases except for the first cohort—when the stripping column fan failed. The ‘Cornell-type’ dual-drain tank was found to rapidly (within only 1–2 min) and gently concentrate and flush approximately 68–88% (79% overall average) of the TSS produced daily within only 12–18% of the tank’s total water flow. Mean TSS concentrations discharged through the three culture tanks’ bottom-center drains (average of 17.1 mg/L) was 8.7 times greater than the TSS concentration discharged through the three culture tanks’ side-wall drains (average of 2.2 mg/L). Overall, approximately 82% of the TSS produced in the partial-reuse system was captured in an off-line settling tank, which is better TSS removal than others have estimated for serial-reuse systems (approximately 25–50%). For the two cohorts of rainbow trout, the partial-reuse system sustained a production level of 35–45 kg per year of fish for every 1 L/min of make-up water, which is approximately six to seven times greater than the typical 6 kg per year of trout produced for every 1 L/min of water in Idaho serial-reuse raceway systems.  相似文献   

7.
Abstract.— We compared growth properties of juvenile spotted wolffish with initial mean weight (±SE) 105.9 (±3.1) g reared in shallow raceways and conventional circular tanks in a 202-d-long growth trial at ambient temperature (approximately 4.0 C). From Day 41 onward, the fish in the shallow raceways was significantly larger, and final mean weights were 356.3 (±18.2) and 318.2 (±15.6), in the shallow raceways and the circular tanks, respectively. Overall, growth rates were 14% higher (0.62%/d) in the shallow raceway group compared to the circular tanks (0.52%/d). Feed conversion efficiency differed and was 17% higher in the shallow raceways (1.01) compared to the circular tanks (0.84). Correlation between adjacent growth rates was more profound in the circular tanks (mean Spearmans rank, r Sp = 0.38) than in the shallow raceways (mean r Sp = 0.15). This could indicate a stronger social hierarchy in conventional tanks leading to suppressed growth, which is in line with the growth data presented in this study. The findings of the present study may have important consequences for optimization of commercial production of spotted wolffish and could be applicable to other bottom-dwelling species.  相似文献   

8.
A dense microbial community develops in the water column of intensive, minimal-exchange production systems and is responsible for nutrient cycling. A portion of the microbial community is associated with biofloc particles, and some control over the concentration of these particles has been shown to provide production benefits. To help refine the required degree of control, this study evaluated the effects of two levels of biofloc management on water quality and shrimp (Litopenaeus vannamei) production in commercial-scale culture systems. Eight, 50 m3 raceways were randomly assigned to one of two treatments: T-LS (treatment-low solids) and T-HS (treatment-high solids), each with four replicate raceways. Settling chambers adjacent to the T-LS raceways had a volume of 1700 L with a flow rate of 20 L min−1. The T-HS raceways had 760 L settling chambers with a flow rate of 10 L min−1. Raceways were stocked with 250 shrimp m−3, with a mean individual weight of 0.72 g, and shrimp were grown for thirteen weeks. Raceways in the T-LS treatment had significantly reduced total suspended solids, volatile suspended solids, and turbidity compared to the T-HS treatment (P ≤ 0.003). The T-LS raceways also had significantly lower nitrite and nitrate concentrations, and the T-HS raceways had significantly lower ammonia and phosphate concentrations (P ≤ 0.021). With the exception of nitrate, there were no significant differences between the change in concentration of water quality parameters entering and exiting the settling chambers in the T-LS versus the T-HS treatment. Nitrate never accumulated appreciably in the T-LS raceways, possibly due to denitrification in the settling chambers, bacterial substrate limitations in the raceways, or algal nitrate assimilation. However, in the T-HS raceways nitrate did accumulate. The T-HS settling chambers returned a significantly lower nitrate concentration and significantly greater alkalinity concentration than what entered them (P ≤ 0.005), indicating that denitrification may have occurred in those chambers. There were no significant differences in shrimp survival, feed conversion ratio, or final biomass between the two treatments. However, shrimp in the T-LS treatment grew at a significantly greater rate (1.7 g wk−1 vs. 1.3 g wk−1) and reached a significantly greater final weight (22.1 g vs. 17.8 g) than shrimp in the T-HS treatment (P ≤ 0.020). The results of this study demonstrate engineering and management decisions that can have important implications for both water quality and shrimp production in intensive, minimal-exchange culture systems.  相似文献   

9.
The most common type of rearing unit for rainbow trout produced in the US is the flow-through raceway. A water treatment structure, which can be readily retrofitted into existing raceways, was designed to create rotational currents to aid in the concentration and collection of particulate waste material in situ. The designed structure, referred to as the Appurtenance for Settleable Solids In-raceway SeparaTion (ASSIST), incorporated a drain line which diverts a small fraction of the raceway flow to continuously remove the uneaten feed and fecal material from the collection area located at the effluent end of the raceway. Continuous removal of the collected particulates minimizes the leaching of soluble material from the solids into the water column. Based on scale model tests using analogous waste material, the ASSIST is expected to remove 40–50% of the settleable solids generated in commercial rainbow trout aquaculture while diverting 5–10% of the raceway flow.  相似文献   

10.
Abstract:   The cephalopod receptor of particle motion was identified. In a previous study, it was suggested that statocysts served this function, but there was no direct supporting evidence, and epidermal hair cells had not been conclusively ruled out. Experiments on Octopus ocellatus were conducted using respiratory activity as an indicator of sound perception. Intact animals clearly responded to 141-Hz particle motion at particle accelerations below 1.3 × 10−3 m/s2, and the mean perception threshold at this frequency was approximately 6.0 × 10−4 m/s2. Specimens in which the statoliths had been surgically removed did not show any response for accelerations up to 3.9 × 10−3 m/s2 at 141 Hz, which was approximately 16 dB greater than the mean perception threshold at this frequency. Specimens that had undergone a control operation in which the statoliths remained intact showed positive responses at 2.8 × 10−3 m/s2 for the same frequency stimulus. This indicates that the statocyst, which is morphologically similar to the inner ear system in fish, is responsible for the observed responses to particle motion in O. ocellatus . This is the first direct evidence that cephalopods detect kinetic sound components using statocysts.  相似文献   

11.
《Aquacultural Engineering》2006,34(4):271-284
Studies were conducted to characterize raceway water quality, effluent water quality, and waste solids within three, raceway-type trout farms. No significant differences were found in effluent water quality between the three farms during 7 months of monitoring. Average effluent quality over the course of the day was not found to be impaired. However, effluent quality was found to change significantly during times of feeding and harvesting. In a concrete/earthen-lined farm, normalized total suspended solids (TSS) concentrations were as high as 115 and 63 mg/l during harvesting and feeding events, respectively. Total Kjeldahl nitrogen (TKN) and ortho-phosphate (OP) also increased with higher TSS loads. The majority of particles (by weight) measured in effluent samples at all three farms were evenly divided between the smallest range (1.5–30 μm) and the largest (>210 μm). For settled sludge samples, the majority of the particles were in the size range of 1.5–30 μm. Particle size in the raceway was positively correlated with fish size during feeding events, but this correlation dissipated during the 4-h period after feeding. The accumulation and characteristics of sludge in a sediment trap were also monitored over a 22-day period.  相似文献   

12.
Sedimentation and Resuspension in Earthen Fish Ponds   总被引：5，自引：0，他引：5  
Resuspension of particles from pond sediment into the water column may be an important nutrient transfer mechanism in aquaculture ponds. However, the magnitude of sediment re-suspension cannot be determined directly because sediment traps collect particles settling from the water column as well as those re-suspended from the pond bottom. We developed a dilution analysis method to differentiate the magnitude of the two particle source fluxes based upon the concentration of soil-derived elements (Si, Al, and Fe) and water-derived elements (C, N) in material collected by sediment traps placed in earthen ponds. Estimated organic C sedimentation from feed residues and algae was compared with trapped organic C as an independent and approximate measure of resuspension. Resuspension fluxes based independently on analyses of three soil-derived elements and on the estimation of expected C sedimentation were similar and accounted for 60–90% of the total solids flux (121–2,676 g/m2 per d) in most ponds sampled. The proportion of total flux that was derived from resuspension in ponds stocked with common carp Cyprinus carpio and tilapia Oreochromis spp . was modeled as a hyperbolic function of fish size and density, with a threshold fish size of 200–300 g. Resuspension flux was conservatively estimated to be equivalent to the daily suspension of a few mm of the pond bottom. These results indicate that sediment resuspension is a major process in carp and tilapia ponds, suggesting that the exchange of nutrients between the sediment and overlying water is intensive.  相似文献   

13.
A three-dimensional (3D) simulation of a commercial-size mixed-cell raceway (MCR) was performed using computational fluid dynamics (CFD). Hydrodynamics of the MCR were fully characterized and validated against experimental data. A simulation of path and residence time of aquaculture-like particles was also conducted to understand solids removal mechanisms and potential efficiencies within a mixed-cell. A structured 3D grid model of one mixed-cell was constructed using 250,000 hexahedral elements, and simulations were conducted using the Realizable k–ɛ turbulence model. From the results of the CFD simulations, average cell rotational velocities, radial velocity profiles, and velocity contour and vector plots were generated at three different water depths. As observed in experimental trials conducted by the authors, predicted velocity contours and vector plots revealed the development of a strong rotational flow in each mixed-cell with lower velocity zones at the center and corners of the cells. Also, a linear trend of increasing rotational velocities from the cell's center to its circumferential perimeter was described. Good fluid-flow pattern agreement was observed between the experimental and predicted vector and contour plots. Average rotational velocities at the bottom (95 cm depth), middle (50 cm depth), and top (20 cm depth) planes of the mixed-cell (1-m water depth) were 17.2, 14.9, and 13.7 cm/s, respectively. Comparison of these velocities with the observed values revealed an overall agreement of nearly 96%. Similarly, when the average velocities at radial distances of the MCR were compared at the three depths, the correlation between the experimental and predicted data was on the range of 89–95%.Simulations of aquaculture-like particles trajectories revealed that roughly 100% of particles larger than 500 μm settled and were removed in less than 15 min through the mixed-cell’ central drain. Also, 100% of the 100-μm particles were removed within one mixed-cell hydraulic retention time (HRT) cycle, with approximately half being removed by the bottom-center drain and half being removed via the upper-side drains. Only 50% of the 10-μm particles was removed; and this mainly occurred through the upper-side drains of the mixed-cell after 17 HRT cycles. Smaller particles appeared to stay in the tank for an indefinite period of time.  相似文献   

14.
Disease epizootics have negatively affected production and expansion of the shrimp culture industry. This, along with environmental concerns regarding limited water resources and contamination of receiving streams, has caused the industry to investigate more sustainable and biosecure management practices. A study was conducted to evaluate the effect of limited water exchange on water quality, growth and survival of the Pacific white shrimp Litopenaeus vannamei postlarvae (PL) in greenhouse-enclosed raceways. Concentrations of NH4-N did not exceed 2.0 mg l−1 during this period; whereas, NO2-N exceeded 26.4 mg l−1, indicating assimilation of primary amines by primary productivity. Periodic removal of suspended solids by a common pressurized sand filter and injection of oxygen into culture water resulted in high-survival rates for both raceways (97.5 and 106.0%) with an average biomass yield of 4.29 ± 0.06 kg m−3. Shrimp samples collected during the nursery trial and at harvest showed no signs of bacterial or viral pathogen infections.  相似文献   

15.
The sessile suspension feeding ascidian, Styela clava , plays an important role in the functioning of estuarine systems. The feeding selectivity of S. clava was examined using standard physiological techniques in terms of particle sizes and diet concentrations. Styela clava increased its retention efficiency (the proportion of available particles retained in ascidian) with increasing particle size at a lower diet concentration [expressed as particulate organic matter (POM)] from 2.11 to 10.06 mg POM L−1, and the highest retention was reached for 5–20 μm particles. With increasing diet concentration to 20.12 mg POM L−1, S. clava retained small particles (<3.5 μm) more efficiently and large ones (>15 μm) less efficiently. The selectivity of ascidian with different sizes was similar at the same concentration. At every diet concentration, larger ascidians retained more 5–20 μm cells than the smaller ones. All these results indicate that S. clava possesses a particle selection mechanism that may affect the zooplankton communities to a certain degree.  相似文献   

16.
Hydroponic plants can efficiently absorb and uptake soluble compounds in wastewater but they have low abilities to remove suspended solids due to the lack of culture media to trap solids. This paper presented an improved hydroponic method for effective treatment of the wastewater from the backwash of recirculating aquacultural systems. The ryegrass (Lolium perenne Lam) was cultured with improved media consisting of perforated plastic plates and several layers of unwoven cotton fabric. The plate/fabric/grass cells with one, three, five, and seven layers of fabric were studied. After one vertical filtration pass through the cells, the removals were 48, 59, 60 and 63% for total solids (TS), 48, 58, 63 and 69% for volatile solids (VS), and 4, 7, 14 and 25% for suspended solids (SS), respectively, for different cells with one, three, five, and seven layers of fabric. It was found that increasing the number of vertical filtration passes through the cells improved the solids removal. The 1-day treatment in the recycling irrigation and treatment system with five cells ( = 0.8 m2 grass) removed 66% TS, 71% VS, and 91% SS, and absorbed 72% total nitrogen (TN), 80% total phosphorus (TP), 63% chemical oxygen demand (COD), and 85% total ammonia nitrogen (TAN). This hydroponic plate/fabric/grass system is a simple and efficient technology for the effective eco-treatment of aquacultural wastewater with relatively high concentrations of suspended solids.  相似文献   

17.
Recirculating raceway systems were examined for their potential as a method for the intensive culture of the marine shrimp Penaeus vannamei Boone. The systems consisted of fiberglass raceways 38 m3 (13.7 m ± 2.4 m ± 1.16 m) and 28 m3 (13.7 m ± 2.4 m ± 0.85 m) each equipped with a vertical screen biofilter, foam fractionators and an ultraviolet ozone generator. All of the systems were enclosed in a commercial greenhouse. Four preliminary growout experiments and two growout experiments with stocking densities of 970 shrimp/m3 and 2,132 shrimp/m3 were completed.
Temperature, pH and salinity remained constant throughout the experiments. Unionized ammonia levels remained below 0.2 mg/L. Nitrite levels ranged from 0.1 to 1.0 mg/L. The 2,132/m2 stocking density resulted in 48% survival, food conversion ratio (FCR) of 1.8 and an average size of 10.8 g. The 970/m3 stocking density resulted in 82% survival, FCR of 2, and an average size of 14 g. Production was 11.4 kg/m3 (114 tons/ha) and 11.0 kg/m3 (110 tons/ha) for the high and low stocking densities, respectively.  相似文献   

18.
ABSTRACT:   The effects caused by suspended particles in seawater and sediment cover of the substrate on the attachment to the substrate of zoospores, and on the subsequent growth and survival of gametophytes of the brown alga Eisenia bicyclis were examined in the laboratory. The attachment rate to the substrate of the zoospores was remarkably reduced by the sediment cover on the substrate, and it decreased to 3.8% of the no-sediment control by a slight sediment cover of 3.0 mg/cm2 (0.048 mm in thickness). The growth of gametophytes was not inhibited at 10 mg/cm2 or less of sediment cover, though it was stopped at 30 mg/cm2. The survival rate of gametophytes became 39.4% at 5 mg/cm2 on the substrate, and gametophytes were all blighted at 30 mg/cm2. The ratio of male to female of the surviving gametophytes became 81.5:18.5, when the sediment cover was 10 mg/cm2. The rate of total loss ( TL [%]) of zoospores and gametophytes of Eisenia bicyclis was obtained from the following equation: TL  = 100 (1 − exp[−0.0339  C ] exp[−1.24  Q ]), where, C (mg/L) and Q (mg/cm2) indicate the concentration of suspended particles in seawater and the sediment on the substrate, respectively.  相似文献   

19.
In order to determine the composition, shape and structure of micro-particles in a cold water recirculating plant raising juvenile Atlantic salmon to the smolt stage, samples of suspended solids, collected on classification meshes, and samples of particles in the culture water were examined microscopically. Concurrent gravimetric tests were attempted which method proved unusable due to clogging of the meshes by a viscid material, especially for particles under 40 μm. It was determined that this viscid material, also evident on the classification screens, constituted a major portion of the less dense particles (1050 kg/m3) by floccing fine particles. Staining indicated that the viscid material was primarily mucus with some gelatinized starches from the feed. Undigested feed stirred in distilled, filtered water were also examined microscopically. Again a viscid coating was found on the filter media, but in this case the primary source appeared to be gelatinized starches. The lighter fraction was essentially absent. In both the culture water and the feed samples, the heavier fraction, 1150 kg/m3, appears to originate primarily from the heavy, brown, indigestible cellulose fraction of the ground wheat in the feed.  相似文献   

20.
Settling velocity characterization of aquacultural solids   总被引：5，自引：0，他引：5  
A top-loading settling column is described and used to characterize the settling properties of the solids in the discharge water from a commercial rainbow trout production facility. Mass-based and phosphorus-based settling curves are presented. The median settling velocity on a mass-basis for the settleable solids was 1.7 cm s−1. The median settling velocity for the settleable phosphorus was 1.15 cm s−1. Manually stripping fecal material from rainbow trout resulted in settleable solids with a median settling velocity of 0.7 cm s−1. Examination of the settling velocity curves show that halving the overflow rate (OFR) from 2 to 1 cm s−1 changes the removal efficiency from 0.61 to 0.73, an increase of about 20%. Halving the OFR again to 0.5 cm s−1 increases the removal efficiency to 0.81, an improvement of about 11%. Settling characteristics of aquacultural solids will vary from facility to facility. The methods described in this paper can be used to perform a similar type of analysis at other aquacultural sites, which may be growing other species under different management regimes.  相似文献   

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