Partitioned Aquaculture System Research Articles

An in-pond tank culture system for high-intensive fish production: Effect of stocking density on growth of grass carp (Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream(Megalobrama amblycephala Yih, 1955)

Pond partitioned aquaculture system is developed in recent years, and it contributes to increasing yield and lowering land occupation. Based on the concept of partitioned aquaculture system, a new in-pond tank culture system (IPTCS) was constructed in this study. This system consists of culture tank, capture and aeration module, waste collection module, and vertical flow constructed wetland (VFCW), and the effective rearing area takes up about 10.05% of the pond area. In IPTCS, grass carp ( Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream ( Megalobrama amblycephala Yih, 1955) were reared at high and low stocking densities for 120 days. The initial density of grass carp in the high and low density groups was 15 kg m −3 and 7.5 kg m −3 , respectively, and that of blunt snout bream were 10 kg m −3 and 5 kg m −3 . During the experiment, the aeration module worked 6 h / day, and the waste collection module worked 5 min / day. The results showed that high stocking density had a negative impact on the growth performance and muscle quality of grass carp and blunt snout bream, and that the water quality in the culture tank gradually was deteriorated with the increasing stocking density. The economic benefits of different stocking densities in this system were investigated in this study, and grass carp high-density rearing failed to generate high benefits, but blunt snout bream high-density rearing leads to a higher income. The feasibility and rearing effect of the in-pond culture tank system were preliminarily confirmed. • A new type of in-pond tank culture system (IPTCS) was constructed. • The economic benefit of theIPTCS was analyzed.

Effects of a partitioned aquaculture system on water quality and growth of Penaeus vannamei

The effects of system partition on the water quality were studied using three shrimp ponds (Ts), and each one of the shrimp pond was connected individually with a fish pond by piping and pump. Three other isolated shrimp ponds were designated as the Cs treatment. The results showed that the implementation of the system can improve the water quality in the shrimp ponds. Particulate organic matter (POM), chemical oxygen demand (COD), nitrite nitrogen (NO2–N) and nitrate nitrogen (NO3–N) in the Ts were lower than those in the Cs during the experiment, and in some cases, they were significantly lower (p < 0.05). Throughout most of the experimental period, the soluble reactive phosphorus in the Ts treatment were greater than that in the Cs treatment (p < 0.05), and N/P ratio of the water column was lower in the Ts treatment than in the Cs treatment throughout most of the experimental period (p < 0.05). These results indicate that the partitioned system contributed to the stability of water quality and N/P ratio in the water. Vibrio parahaemolyticus was dominant in the third to seventh weeks in Cs, and the dominant condition was found only in seventh week in Ts. The result indicated that system may contribute to the slowing down of the breakout of V. parahaemolyticus in the shrimp pond. According to the redundancy analysis, COD, chlorophyll a and POM were mainly positively related to the dominance index of V. parahaemolyticus, and maybe POM can serve as an indicator to reflect the trend of V. parahaemolyticus.

Pumping Performance of a Slow‐Rotating Paddlewheel for Split‐Pond Aquaculture Systems

AbstractCommercial catfish farmers are intensifying production by retrofitting ponds with variations of the partitioned aquaculture system. The split‐pond system is the most common variation used commercially. The split‐pond consists of a small fish‐holding basin connected to a waste treatment lagoon by two conduits. Water is circulated between the two basins to remove fish waste and provide oxygenated water to the fish‐holding basin. Although much research has been devoted to algal and fish production dynamics in variations of the partitioned aquaculture system, little information is available on basic engineering considerations for devices to circulate water in these systems. This study evaluated performance characteristics for a slow‐rotating paddlewheel pump that looked at the relationships among power input, rotational speed (circular tip velocity), water velocity, and water flow rate. Rotational speeds of 1.0, 2.0, 3.0, and 4.0 rpm were evaluated in open channels and in channels with fish barriers. Measured power input was greater than the calculated power input for all four rotational speeds and ranged from 0.11 to 1.80 hp. Water flow rate ranged from 4,548–19,330 gal/min and water discharge per unit power input decreased dramatically as rotational speed increased. Installation of fish barriers decreased channel open area and the resulting frictional losses reduced water flow rates. Results from this study provide initial pump performance data for designing split‐pond aquaculture systems.

Effect of temperature and phytoplankton concentration of Partitioned Aquaculture System water on freshwater mussel filtration

AbstractThe freshwater mussel Elliptio complanata wasprovided green algal-dominated water from a Parti-tioned Aquaculture System (PAS) over a range ofwater temperatures (6.1^32.41C) and suspendedparticulate organic carbon (POC) concentrations(o1^32.2mgCL 1 ) to determine ¢ltration rates asmgPOCkg 1 wet tissue weighth . The lowest ¢l-tration rates were observed at lowest temperaturesand POC concentrations while thehighest rates wereat intermediate temperatures and the highest POClevels. The predicted ¢ltration rate (PFR) in responseto water temperature and POC concentrations wasas follows: lnPFR51.4352 10.1192 POC 10.1399T 0.0001 T 3 . Within the experimental conditions,PFRs at any POC concentration increased withincreased water temperature to a peak at 221Candthen decreased. The maximum PFR occurredat 22 1Cand32mgCL 1 and the minimum PFRat 7 1Cand1mgCL 1 . A model to describe themussel ¢ltration rate responses to PAS waterconditions involves both water temperature and POCconcentration.Keywords: ¢ltration rate, freshwater mussel, PAS,culturesystemIntroductionA Partitioned Aquaculture System (PAS) separates aculture pond into four distinct components (paddle-wheels, algal basin, ¢lter-feeder area and culturespeciesarea)linkedbyahomogeneouswatervelocity¢eld (Brune, Schwartz, Eversole, Collier & Schwedler2004). Paddlewheels provide watercurrent, nutrientmixing,uniformsunlightexposuretophytoplanktonandcontinuous£owoverthealgalbasin,¢lterfeederand cultured species areas. Phytoplankton inthe al-galbasin(95%ofthePASarea)useinorganic¢shme-tabolic wastes (nutrients) to sustain high primaryproductivity levels. Feeding rates and ¢sh carryingcapacityof thePASisaboutthreeto ¢vetimesthatofconventional cat¢sh culture ponds because of sus-tained high phytoplanktonproductivity (Brune etal.2004).Filter-feedingorganisms,byharvestingphyto-plankton, reduce cell age and stabilize a standingcrop of faster-growing phytoplankton cells at re-duced respiration rates and increased oxygen pro-ductionper watervolume(Bruneetal.2004).Someofthetermsusedinliteraturetoexpress¢ltra-tion activity of suspension feeders include clearancerate, pumping rate, ¢ltration rate, ingestion rate, up-take rate, and retention rate (see, e.g. Foster-Smith1975; Walz 1978, Winter 1978; Riisgrd 2001a). Theterm ¢ltration rate inthis studyand inthis paper re-fers strictly to the amount of suspended phytoplank-ton(seston)removedfromthewatercolumnperunittimeandincludesboththose¢lteredparticlesconso-lidated in pseudofaeces and those consumed, and isidentical to the terms uptake rate and retention rateof Foster-Smith (1975) andWalz (1978).The role of a¢lterfeederinstabilizingalgalstandingcropbiomassin PAS water is more appropriately estimated usingthis de¢nition of ¢ltration rate than measures esti-matingtheamountofwater¢lteredoringestionrate.

Production Characteristics of Channel Catfish, Ictalurus punctatusStocked at Two Densities in the Partitioned Aquaculture System

This study was conducted to determine if channel catfish could be cultured at an increased density in the Partitioned Aquaculture System (PAS) without significantly affecting performance. Channel catfish fingerlings (36.53±6.76 g; mean ±SD) were initially stocked into six 9.15 m3 sections at 3,461±317 fish per section, twice the designed carrying capacity, and fed twice daily to satiation. After 75 days, the density of three units was reduced by approximately 50% and all six units were fed for another 97 days. There was no significant difference (P > 0.05) in mean growth rate, feed conversion ratio, or production between fish grown at the low- and high-density treatments. Also, length variation (CV) and condition factors (K) were similar (P > 0.05) between fish grown at the low and high-density. Increasing density by twice the designed carrying capacity did not affect performance of channel catfish in the PAS.

Effect of Silver Carp Hypophthalmichthys molitrix and Freshwater Mussel Elliptio complanata Filtration on the Phytoplankton Community of Partitioned Aquaculture System Units

AbstractGrowers produce over 2.8 million kg of catfish (over $350 million wholesale revenue) annually in the United States. The microbiology of the phytoplankton community in culture water affects the growth and flavor of the catfish and is a consideration for growers. Filter feeders, like silver carp and freshwater mussels, in controlled growth systems are used to adjust the phytoplankton species. Our goal was to successfully control the algal populations with filter feeders in catfish production. We used silver carp Hypophthalmichthys molitrix as a filter feeder in Partitioned Aquaculture System (PAS) water. Silver carp completely eliminated the cyanobacteria Microcystis by size and biovolume reduction. This created the desired effect of small green algae dominating the algal community. A significant but opposite change was observed when freshwater mussels Elliptio complanata filtered PAS water resulting in Microcystis biovolume and size dominance in the PAS; a less desirable algal community. This study also showed an immediate shift in the phytoplankton community when silver carp and mussels were interchanged between PAS waters. The size‐selective filtration by the two filter‐feeding taxa was important in determining the composition of the PAS phytoplankton community, and it was apparent that filtration with silver carp successfully depleted undesirable algae.

Intensification of pond aquaculture and high rate photosynthetic systems

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.

Comparative Nile tilapia and silver carp filtration rates of Partitioned Aquaculture System phytoplankton

Abstract Nile tilapia ( Oreochromis niloticus ) and silver carp ( Hypophthalmichthys molitrix ) held in timed-pulse feeding chambers were provided water dominated either by green algae ( Scenedesmus , Ankistrodesmus and Tetraedron ) or by cyanobacteria ( Microcystis ) to compare filtration rates (FRs). FRs were expressed as suspended particulate organic carbon (POC)/kg wet fish weight/h and as phytoplankton units filtered based on counts. Nile tilapia and silver carp filtration significantly reduced phytoplankton number of both taxonomic groups with the larger phytoplankton being filtered proportionally more than the smaller phytoplankton. Nile tilapia FR of green algae was significantly higher than silver carp; however, silver carp FR of cyanobacteria was higher than Nile tilapia. Ivlev's 90% saturation FRs (FR 90 ) in green-algal and cyanobacterial water sources were 702 and 812 mgC/kg/h for Nile tilapia and 414 and 1028 mgC/kg/h for silver carp, respectively. Silver carp were observed to reach these FR 90 values at lower POC concentrations than Nile tilapia with both green algae and cyanobacteria.

Filtration of green algae and cyanobacteria by Nile tilapia, Oreochromis niloticus, in the Partitioned Aquaculture System

Nile tilapia, Oreochromis niloticus, held in a timed pulse fed Continuous Stirred Tank Reactor (CSTR) were provided Partitioned Aquaculture System (PAS) algal-rich water dominated by green algae (i.e., Scenedesmus and Ankistrodesmus) and cyanobacteria (i.e., Microcystis and Merismopedia) to determine filtration rates (FR). A similar number and size of tilapias were stocked at 1.5 kg/tank into each of the six CSTRs (127 l) for 58-h experiment period. The cell counts of phytoplankton in water filtered by tilapias indicated significant reduction in green algae and cyanobacteria. Nile tilapia was more effective filtering the larger particle size taxa in both water sources. FR measured as mg of particulate organic carbon (POC) per kg wet fish weight per hour increased as POC increased. A curvilinear filter-feeding rate model provided a maximum filtration rate (FR max) of 641 mgC/kg/h at 26 mgC/l in green algal-dominated water. The projected FR max of cyanobacterial-dominated water was 865 mgC/kg/h at 59 mgC/l. The derived filter-feeding rate models will help to describe Nile tilapia filtration kinetics in the PAS and the potential for control of nuisance cyanobacteria.

Profitability comparison of the partitioned aquaculture system with traditional catfish farms

The Partitioned Aquaculture System (PAS) provides a promising intensive aquaculture technology that is efficient and profitable, while simultaneously solving a variety of culture problems. This creates a sustainable aquaculture technology, which is environmentally safe and economically feasible. The PAS eliminates water discharge and reduces land usage and ground water requirements. The PAS system production process was modeled for catfish production using a growth model developed from observed data. The results of the PAS economic analysis were compared with two traditional catfish production scenarios. Comparisons were made between estimated investment requirements, operating costs and internal rates of return and breakeven points for alternate production systems and land ownership status. The results look promising, but research is ongoing on how best to manage the filter feeder component of the PAS.

Filtration of Green Algae and Cyanobacteria by Freshwater Mussels in the Partitioned Aquaculture System

Abstract.— The freshwater mussel Elliptio complanata was provided water containing green algae and cyanobacteria delivered from the Partitioned Aquaculture System (PAS) at eight flow rates to determine algal filtration rates as mg of particulate organic carbon (POC)/kg wet tissue weight per h. The dominant taxon in cyanobacterial waters was Microcystis while the dominant taxa in green algal waters were Scenedesmus and Ankistrodesmus. The cell counts of Scenedesmus and Ankistrodesmus were the only algal taxa that were significantly different between the incoming water and water filtered by mussels. Filtration rates of POC obtained from green algal water were significantly greater than from cyanobacteria‐dominated waters at all flow rates. A significant increase in mean filtration rate was observed as flow rates increased. The filtration rate of green algae increased as POC concentration increased, peaking at 28 mg C/L. A maximum filtration rate was not observed with cyanobacterial waters.

The partitioned aquaculture system: impact of design and environmental parameters on algal productivity and photosynthetic oxygen production

Fish production in pond culture systems is often limited by the dissolved oxygen (DO) concentration. Algal productivity greatly impacts the DO concentration but is difficult to control in traditional pond systems. The partitioned aquaculture system (PAS) was designed to increase fish production in pond systems by increasing net oxygen production through management of algal productivity and biomass concentration. This initial research was conducted to establish algal productivity and biomass levels in the PAS as a function of algal cell retention time, nutrient addition rate, water depth, and mixing and to characterize the photosynthetic oxygen production rate as a function of solar radiation. In order to focus on algal productivity, an inorganically fertilized PAS without fish was operated for this study. Algal productivity in the PAS was greater for the cell retention time of 1.2 days than 2.5 days, greater for external inorganic carbon addition rates of 0.6 and 1.2 mmol/l per day than for 0 mmol/l per day addition rate, greater for the water depth of 34 cm than 66 cm, and greater for the water velocity of 12.5 cm/s than 3.1 and 6.2 cm/s. Algal productivity rates of 5–10 g C/m 2 per day were achieved. Algal culture composition was impacted by inorganic carbon addition. Over a 2-year period, the algal culture was composed primarily of blue–green algae (Cyanophyta) when no external inorganic carbon was added, and green algae (Chlorophyta) at external inorganic carbon addition rates of 0.6 and 1.2 mmol/l per day. The maximum gross photosynthetic oxygen production rate at 20°C was found to be 0.096 mg O 2/mg TSS per hour for predominantly blue–green algal cultures and 0.14 mg O 2/mg TSS per hour for green algal cultures. Corresponding maximum algal specific growth rates, calculated using a literature value for algal cell composition, were 0.077 and 0.12/h for blue–green and green algae, respectively.