Optimizing nutrient utilization, hydraulic loading rate, and feed conversion ratios through freshwater IMTA-aquaponic and hydroponic systems as an environmentally sustainable aquaculture concept
Metadata
- Cite key: godaOptimizingNutrientUtilization2024
- Item type: Journal Article
- Authors: A. Goda, A. Aboseif, M. Taha, E. Mohammady, N. Aboushabana, H. Nazmi, M. Zaher, H. Aly, M. El-Okaby, N. Otazua, M. Ashour
- Affiliation: National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt (all authors except Otazua); INKOA SISTEMAS, S.L., Ribera de Axpe 11, Edificio D1, Dpto 208, 48950 Erandio, Spain (Otazua)
- Journal: Scientific Reports 14 (2024) 14878
- Date: 06/2024
- Date added: [not reported]
- DOI: 10.1038/s41598-024-63919-7
- Funding: IRAHS project (Integration of Recirculating Aquacultural and Hydroponics using Renewable Energy System), Science & Technology Development Fund (STDF), Ministry of Scientific Research, Egypt, grant 2252 (first-cycle data); HortiMED Project (PRIMA program / EU Horizon 2020), grant 1915 (second-cycle data); open access funding via STDF/Egyptian Knowledge Bank (EKB)
- URL: https://doi.org/10.1038/s41598-024-63919-7
- PDF:
Goda et al. - 2024 - Optimizing nutrient utilization, hydraulic loading.pdf
Opinion
An ambitious, data-rich five-species IMTA-aquaponics pilot (tilapia, catfish, mullet, prawn, mussels + eight vegetable crops across two hydroponic types), and the N/P mass-balance framework is genuinely useful. But the reporting has real problems: the paper’s own headline biomass figures for the IMTA system are internally inconsistent by a wide margin (see Extraction notes, WARN-BLOCK), a table footnote appears to swap the definitions of NO2 and NO3, and there is no described replication at the system level — each of “IMTA”, “IMTA-FRS”, and “IMTA-NFT” reads as a single physical set of ponds/troughs, with “first cycle vs second cycle” doing double duty as if it were a spatial replicate. The letter-based significance testing (a/b superscripts) in Tables 3-5 compares cycle-to-cycle, which is a much weaker claim than a true treatment replicate comparison. Useful for the mass-balance methodology and general engineering description of a five-species freshwater IMTA-aquaponics rig; the specific biomass totals should be treated with caution and verified against the underlying data before citing.
Abstract
Water quality in land-based fish production can be controlled through either instantaneous water exchange or costly wastewater treatment followed by recirculation. Agricultural-aquaculture integration is an excellent alternative technique for reducing nutrient discharge levels, boosting profitability, and converting fish culture wastewater into valuable products. The current study employed a solar energy system to power two separate IMTA-aquaponics systems (Nutrient Film Technique, NFT, and Floating Raft Systems, FRS) for the cultivation of Nile tilapia, African catfish, thin-lipped grey mullet, freshwater crayfish, freshwater mussels, and a variety of vegetables. Tilapia and catfish were fed exclusively on diets under the IMTA system. All wastewater from tilapia and catfish ponds, both dissolved and solid, flows sequentially to ponds containing other cultivated species. The water then flows through the IMTA system’s terminal point to the NFT and FRS systems before returning to the tilapia and catfish ponds, allowing complete control of the nutrient flow throughout this entire circular system. Two 147-day production cycles were concluded. The results from the second production cycle are reported. Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems. The current IMTA system had a cumulative feed conversion ratio (FCR) of 0.90, while the FCRs for tilapia and catfish were 1.28 and 1.42, respectively. Nile tilapia and catfish consumed 571.90 kg of feed containing 25.70 kg of nitrogen (N) and 9.70 kg of phosphorus (P), reflecting, and gaining 11.41 and 3.93 kg of dietary N and P, representing 44.40 and 40.46% dietary N and P retention, respectively. In the IMTA system, the addition of mullet and prawn as detrivores aquatic animals improves dietary N and P utilization efficiency to 59.06 and 51.19%, respectively, while the addition of mussels as herbivore animals improves dietary N and P utilization efficiency to 65.61 and 54.67%, respectively. Finally, using FRS and NFT as hydroponic systems increased dietary N and P efficiency to 83.51% N and 96.82% P, respectively. This study shows that the IMTA-Aquaponic system, as a bio-integrated food production system, can convert the majority of fish-fed residues into valuable products suitable for desert, rural, and urban areas in impoverished and developing countries.
Summary
The authors ran a freshwater IMTA-aquaponics pilot at a NIOF station in Egypt, cascading water from tilapia and catfish ponds through mullet/prawn and mussel ponds, a sand filter, and a biological filter, before splitting it into two parallel hydroponic setups — a Floating Raft System (FRS, 20 m², HLR 4.8 m/day) and a Nutrient Film Technique unit (NFT, 122 m of channel, HLR 6.4 m/day) — each growing a different mix of vegetables. Two 147-day production cycles were run; only the second cycle’s results are reported in detail (first-cycle data appear only in the summary tables). The paper tracks nitrogen and phosphorus mass balances step-by-step through the trophic chain (fed fish → detritivores → filter-feeding mussels → plants), reporting that dietary N retention rose from 44.4% (tilapia+catfish alone) to 65.6% (with mullet, prawn, mussels) to 83.5%/74.3% once FRS/NFT hydroponics were added, with a similar pattern for phosphorus (40.5% to 54.7% to 96.8%/79.8%). Growth, feed-utilization, and proximate-composition data are reported per species (Tables 3-5), and a full N/P budget is tabulated per hydroponic configuration (Tables 6-7). The paper argues this five-species IMTA-aquaponics design out-performs simple fish monoculture on both feed conversion and nutrient recovery, and could be scaled for small farmers in water-scarce regions like Egypt. It is good for the general engineering layout of a multi-species IMTA-aquaponics rig and its N/P accounting method; it is not a strong source for definitive biomass totals given the internal inconsistencies described below.
Experiment data
- Location: El-Kanater El-Khayria fish station, National Institute of Oceanography and Fisheries (NIOF), Kalubiya Governorate, Egypt
- Design: Non-replicated comparison of two parallel IMTA-aquaponics configurations (IMTA-FRS vs IMTA-NFT), each fed by an identical five-species IMTA aquaculture chain (Nile tilapia, African catfish, thin-lipped grey mullet, freshwater prawn, freshwater mussels), run over two sequential 147-day production cycles; only second-cycle results are reported as the primary findings
- Replicates / n: No stated system-level replication (each of IMTA / IMTA-FRS / IMTA-NFT appears to be a single physical set of ponds/troughs). n=3 is used only for analytical sub-sampling (proximate body composition; growth/FCR significance letters in Tables 3-5, which compare first vs second cycle, not spatial replicates)
- Duration: 147 days per production cycle (two cycles total; second cycle reported)
- Organisms: Nile tilapia (Oreochromis niloticus), African catfish (Clarias gariepinus), Thin-lipped grey mullet (Liza ramada), Freshwater prawn (Macrobrachium rosenbergii), Freshwater mussels (Aspatharia chaiziana, A. marnoi) / vegetables: red & green leaf lettuce, head lettuce, bell pepper, chili pepper, eggplant, tomato, cucumber, broccoli
- Statistics: Shapiro-Wilk & Bartlett’s tests (normality); Student’s t-test (fish/prawn/mussel growth, feed utilization, production); one-way ANOVA + Duncan’s multiple range test, p<=0.05 (plant production, nutrient removal); SPSS v.17.0
- Feed Conversion Rate (FCR): IMTA-system cumulative FCR 0.90 (stated); Tilapia 1.28+/-0.11, Catfish 1.42+/-0.24 (measured, second cycle); Mullet 1.24, Prawn 1.21, Mussels 0.90 (all “estimate” values per Table 4 footnote)
- Hydraulic Loading Rate (HLR): IMTA (fish ponds only) 2.4 m/day; IMTA-FRS 4.8 m/day; IMTA-NFT 6.4 m/day (Qw = 96 m3/day for all, HLR = Qw / trough surface area)
- Nitrate (NO3) / Nitrogen (N) retention: 44.40% (tilapia+catfish alone) -> 65.61% (+ mullet, prawn, mussels) -> 83.51% (+ FRS) / 74.29% (+ NFT), second cycle
Hydraulic loading rate and water flow
This paper: A single 16 m3/h self-priming well-water pump runs for 6 h/day, giving Qw = 96 m3/day for every system. HLR = Qw / trough surface area, giving 2.4 m/day for the fish-pond block (“IMTA”), 4.8 m/day for IMTA-FRS (20 m2 bed), and 6.4 m/day for IMTA-NFT (122 m of channel, per Table 1’s own footnote correcting the “m3” column header to “total area by m”). Increasing HLR is reported to increase NH3-N, NO2-N, NO3-N and TP removal (%) in both NFT and FRS, and plant production is reported to increase alongside HLR up to 4.8 m/day (FRS) and 6.4 m/day (NFT).
Compared with:
- todo Endut et al. 2010 — cited (ref 17) as the source of the HLR = Qw/area equation used here; original optimal-HLR findings not reproduced in this note.
- todo Yang & Kim 2020 — a separate paper already in this vault testing HLR directly (high/medium/low flow rate arms) on lettuce/Chinese cabbage/mustard/chia/basil/Swiss chard; a natural comparison point for this paper’s HLR claims but not cross-checked here.
Nitrogen and phosphorus mass balance
This paper: Feed-borne N and P are tracked step-by-step: tilapia+catfish consumed 571.90 kg feed (25.70 kg N, 9.70 kg P) and retained 44.40%/40.46% of dietary N/P; adding mullet+prawn raised retention to 59.06%/51.19%; adding mussels raised it to 65.61%/54.67%; adding FRS or NFT hydroponics raised it to 83.51%/96.82% (FRS) or 74.29%/79.81% (NFT) (Figs. 3-4, Tables 6-7).
Compared with:
- todo Otazua et al. (Ibáñez Otazua, in Biology and Life Sciences Forum, ref 36/59) — same research group’s related IMTA-aquaponics work, cited as having “previously demonstrated” IMTA-aquaponics outperforms monoculture; not independently checked here.
Linked claims
- IMTA polyculture increases dietary nitrogen and phosphorus retention efficiency
- Higher hydraulic loading rate increases nitrate accumulation and reduces ammonia peak duration
- Aquaponics can reduce reliance on chemical fertilizer inputs
Citations to chase
- todo Endut, A. et al. (2010) — source of the HLR = Qw/area equation and prior optimal-HLR/plant-ratio findings in recirculating aquaponics
- todo Ibáñez Otazua, N. et al. — companion IMTA-aquaponics study from the same research group/station
- todo Goda, A. M. A. et al. (2015) — “Bio economic features for aquaponic systems in Egypt”, same lead author, likely origin of the monoculture comparison figures flagged below
Extraction notes
⚠️BLOCK Fish/system biomass totals for the IMTA system are internally irreconcilable.
- Abstract: “Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems.”
- Results, “Influences of IMTA system on feed utilization and feed conversion ratio” (p.9): “The total biomass of all aquatic animals in the IMTA system was 736.46 kg, as opposed to 145.49 kg for tilapia and 271.01 kg for catfish in monoculture systems.” (repeats the Abstract’s “monoculture” framing for 145.49/271.01)
- Results, “Nitrogen (N) balance” (p.9): “In the IMTA system, tilapia and catfish consumed 186.05 and 385.85 kg of feed 40 m−3… and gained 145.49 and 271.01 kg 40 m−3” — here the same two numbers (145.49, 271.01) are attributed to tilapia’s and catfish’s own gain inside the IMTA system, directly contradicting the two passages above that call these numbers separate “monoculture” system totals.
- Table 2 (Production table), “IMTA” column, second cycle: Nile tilapia = 157.12 kg, Catfish = 323.00 kg, Total = 868.83 kg — none of these three figures match 145.49, 271.01, or 736.46.
- No Methods description of any standalone monoculture control pond exists anywhere in the paper (Methods describes only the single cascading five-pond IMTA design), so it cannot even be confirmed that a monoculture comparison arm was actually run in this study, versus a citation of the authors’ own prior work (ref. 20, Goda et al. 2015) left unlabelled as external.
- Cannot determine which total (736.46 vs 868.83 kg) is the true IMTA second-cycle biomass, nor whether 145.49/271.01 belong to tilapia/catfish’s IMTA-internal gain or to an (undescribed) external monoculture comparison. Recorded
Fish biomass created (kg)= UNCLEAR in both trial rows. All four candidate figures and their locations are listed here and inExperimental Remarks. - Downstream effects: the paper’s own headline FCR-improvement narrative (aquaculture-only vs whole-IMTA) and any recomputation of feed-to-biomass ratios inherit this uncertainty. Added to
REVIEW.md.
⚠️MATERIAL Table 1 footnote appears to swap NO2/NO3 definitions. Table 1’s footnote reads “NO2 nitrate, NO3 nitrite” — i.e., it defines the row labelled “NO2” as nitrate and the row labelled “NO3” as nitrite, backwards from standard chemical nomenclature. This also contradicts: (a) the row labels themselves (which use the standard formulas NO2 and NO3), and (b) the paper’s own Discussion, which uses “NO3-N” consistently to mean nitrate accumulating after nitrification (“increasing NO3-N leads to improved TAN elimination, indicating greater nitrification… Since NO3-N accumulates in the system, once NH3-N is nitrified, denitrification becomes limited,” p.11) and treats “Nitrite-N” and “Nitrate-N” as distinct, standard quantities elsewhere in the same paragraph. Recorded NO2-N and NO3-N using the standard convention (NO2=nitrite, NO3=nitrate), i.e. the footnote’s apparent word-swap was not followed — basis: row labels + body-text usage both agree against the isolated footnote wording. Affects NO2-N and NO3-N cells in both trial rows.
⚠️CHECK NFT lettuce planting density given in incompatible units. “using 3 plants m−1 and 15 plants m−2 for head lettuce as a higher density in IMTA-NFT (122 m) and IMTA-FRS (20 m2)” (p.7) gives NFT density as 3 plants per linear metre of the 122 m channel. Two sentences later, for red/green leaf lettuce: “observed in IMTA-NFT and IMTA-FRS at densities of 3 and 15 plant m−2, respectively” (p.7) gives NFT density as 3 plants per square metre — same numeral, different unit, same system, adjacent sentences, no reconciling statement and no stated channel width to convert between the two. Recorded Plants/m2 = UNCLEAR for IMTA-NFT (T2); IMTA-FRS’s figure (15 plants/m2, head lettuce; consistent across both sentences) recorded for T1. Added to REVIEW.md.
⚠️MINOR Table 1 vs Table 2 “Total area” for IMTA-NFT: Table 1 gives “122#” with footnote “#total area by m” (i.e. 122 m, a length, matching Methods’ “two NFT hydroponic units (122 m each)” and Results’ “IMTA-NFT (122 m)” — stated 3x consistently). Table 2 gives “Total area (m)” = 15 for NFT (both cycles), which numerically equals the “15 plants m−2” density used for a different system (FRS) in a nearby sentence, suggesting a possible copy/mislabel in Table 2’s NFT cell. No dedicated trials.csv column exists for trough area/length, so no cell is affected; noted for context only.
⚠️MINOR Running text mislabels a unit: “A total production of red and green leaf lettuce (82.22 and 89.54 plants) and (35.20 and 37.60 kg)” (p.7) — 82.22/89.54 are labelled “plants” (a count) but exactly match Table 2’s NFT second-cycle kg values for red/green leaf lettuce. Table 2’s values used directly; unaffected.
⚠️MINOR Initial tilapia/catfish body weights: Methods (p.4) states “Tilapia fingerlings with an initial body weight of 25.4+/-1.7 g” and “Catfish weighing 173.27+/-5.64 g,” which do not exactly match Table 3’s “First cycle” IBW column (28.30+/-1.22 g tilapia; 161.00+/-26.40 g catfish). Table 3’s Second cycle IBW (20.4+/-1.70 g tilapia; 131.27+/-7.60 g catfish) — used here as the primary Fish size initial value since the paper’s own reported results are the second cycle — is not itself directly contradicted by a second textual source (plausibly a fresh restock between cycles), so no BLOCK is raised against the value actually recorded. The Methods-vs-Table-3-first-cycle mismatch is noted for completeness only.
⚠️MINOR Ambiguous “respectively” pairing: “Nile tilapia and catfish were only fed an experimental diet (30.58% and 19.38 MJ gross energy/kg, respectively)” (p.4) literally pairs tilapia->30.58% and catfish->19.38 MJ/kg (two different metrics for two different fish), when it more plausibly means the single diet fed to both species was 30.58% crude protein and 19.38 MJ/kg gross energy. Recorded Protein = 30.58% (applied to the shared diet) with this caveat.
Not flagged (observation only, no contradiction): the paper’s stated “cumulative IMTA FCR” of 0.90 (Abstract, Results p.9, Conclusion — consistent across all three mentions) happens to equal Mussels’ own individually-tabulated “estimated” FCR (Table 4, second cycle, 0.90) exactly. A sanity-check recomputation of total feed (571.90 kg, tilapia+catfish only) / total IMTA biomass (736.46 kg, per Abstract) gives ~0.78, not 0.90 — but since no second textual value contradicts 0.90 and the authors never state their system-level aggregation formula (Eq. 6 is given per-individual only), this is recorded as-is rather than flagged; the 0.78 recomputation is not entered in any cell and is shown here only as verification evidence.
[not reported]:
- Fish/Fish Category as a single controlled term (paper uses functional roles: “detritivores” for mullet/prawn, “herbivore”/filter-feeder for mussels, p.1)
- Initial Stock density in kg/m3 (paper gives count-based densities per species: 15 fish/m3 tilapia, 10 fish/m3 catfish, 50 fry/m3 mullet, 84 prawn/m2, 2.5 kg/m2 mussels — none convert to kg/m3 without multiplying by individual weight, which is derivation)
- SGR, Fish size initial/final, survival, weight gain as single system-level values (paper reports these per species; see
Experimental Remarksfor full per-species breakdown) - N, P, K feed composition as percentages (paper states absolute kg of N/P in total feed, not % composition)
- Water volume in the system as a single total (paper states each compartment’s volume individually — 5x40 m3 ponds, 20 m3 FRS bed, 6 m3 biofilter, 3 m3 sump — but never sums them; NFT trough volume is never stated at all)
- Daily Water exchange rate (paper states ~5% of system volume per week, not a daily figure)
- Lat/Long coordinates (station name and governorate given; no coordinates stated)
- FUE AP / FUE HYD / WUE as such (paper reports dietary N/P retention % instead; see
NO COLUMNnote below) - Plant height, leaf count, SPAD, tissue nitrate (not measured/reported for any plant species)
- Days Plant after transplant to first harvest (given only as a species-dependent range, 33-45 to 80-90 days; no single value)
NO COLUMN items (Experimental Remarks holds the detail):
- Full per-species growth/FCR/PER/PPV/ER tables (mullet, prawn, mussels) — schema has no polyculture-breakdown columns
- Dietary N and P utilization efficiency progression (the paper’s central finding) — no dedicated efficiency-% column exists distinct from FUE AP/HYD, which is ambiguous here since there is no hydroponic-only control
- BOD, COD, TA, TSS, PO4, TP water-quality values from Table 1 — no dedicated columns
- Individual compartment water volumes (5x40 m3 ponds, 6 m3 biofilter, 3 m3 sump, 20 m3 FRS bed)
- Proximate body composition (DM, CP, EE, ash, GE) for all five species (Table 5)
Extraction notes: severity tally and quality score
BLOCK: 1 (fish/system biomass totals). MATERIAL: 1 (NO2/NO3 footnote swap). CHECK: 1 (NFT lettuce density units). MINOR: 5 (do not count toward score). Per SCHEMA.md (1 BLOCK -> caution; 2+ BLOCK, 5+ MATERIAL, or misattribution -> suspect), this paper would land on caution by count alone. It is scored suspect instead because the BLOCK item is a headline outcome (total system biomass) with four mutually incompatible candidate values spanning the Abstract, two Results passages, and a table — a wider and more central inconsistency than a single-BLOCK case, and one that a reader citing this paper’s flagship “736.46 kg” figure would very likely reproduce without noticing the conflict.
Source: Goda et al. - 2024 - Optimizing nutrient utilization, hydraulic loading.pdf
Data Tables
Structured data extracted from this paper into the vault's
trials.csv/plant_measurements.csvdatasets. Fields the paper didn't report are omitted. Download the full datasets (measurements).
Trial Parameters
godaOptimizingNutrientUtilization2024-T1
Fish
| Field | Value |
|---|---|
| Fish | Nile tilapia (Oreochromis niloticus); African catfish (Clarias gariepinus); Thin-lipped grey mullet (Liza ramada); Freshwater prawn (Macrobrachium rosenbergii); Freshwater mussels (Aspatharia chaiziana, A. marnoi) — IMTA polyculture, identical aquaculture chain feeding both FRS and NFT hydroponic units |
| FCR | System cumulative FCR (stated) = 0.90 (see Extraction notes, not flagged as contradiction but does not reconcile with a simple feed/biomass recompute); per-species second cycle (Table 4): Tilapia 1.28 +/- 0.11, Catfish 1.42 +/- 0.24 (measured); Mullet 1.24, Prawn 1.21, Mussels 0.90 (estimate values per footnote) |
| SGR | Tilapia 1.77 +/- 0.30 %/day; Catfish 1.24 +/- 0.22; Mullet 2.11 +/- 0.17; Prawn 3.31 +/- 0.32; Mussels 0.92 +/- 0.42 (second cycle, Table 3) |
| Protein | 30.58 (crude protein %, diet fed to tilapia and catfish; ambiguous ‘respectively’ pairing in text, see Extraction notes) |
| Fish size initial | Tilapia 20.4 +/- 1.70 g; Catfish 131.27 +/- 7.60 g (IBW, second cycle, Table 3; conflicts with Methods-stated 25.4 +/- 1.7 g / 173.27 +/- 5.64 g, see Extraction notes) |
| Fish size final | Tilapia 275.65 +/- 2.14 g; Catfish 815.65 +/- 8.20 g (FBW, second cycle, Table 3) |
| Feed routine | Quantity of feed consumed daily adjusted based on periodic weighings; initial sampling day 30 post-stocking, then every 15 days (p.4) |
| Feed regime | Experimental diet, 30.58% crude protein / 19.38 MJ gross energy per kg (p.4); 2-week pre-trial acclimation on same diet |
| Total Feed (kg) | 571.90 (tilapia + catfish combined, second cycle, stated Abstract/Results); Tilapia 186.05 kg, Catfish 385.85 kg (Table 6, per 40 m3 pond) |
| Fish biomass created (kg) | UNCLEAR — see Extraction notes WARN-BLOCK. Candidates: Total IMTA = 736.46 kg (Abstract/Results p.9) vs 868.83 kg (Table 2, IMTA column, second cycle); Tilapia = 145.49 kg (Abstract ‘monoculture’, also reused as IMTA-internal gain in N-balance section p.9) vs 157.12 kg (Table 2); Catfish = 271.01 kg (same dual use) vs 323.00 kg (Table 2) |
| Fish survival rate | Tilapia 95% (estimate); Catfish 99% (estimate); Mullet 51% (estimate); Prawn 27% (estimate); Mussels 66% (estimate) (second cycle, Table 3 ‘S’ column, footnoted as estimate values) |
| Fish weight gain | Tilapia 255.25 +/- 1.73 g/fish; Catfish 684.38 +/- 8.10 g/fish; Mullet 112.04 +/- 1.70 g/animal; Prawn 25.69 +/- 0.61 g/animal; Mussels 361.8 +/- 36.20 g/animal (second cycle, Table 3) |
| Fish trial duration (days) | 147 |
Water
| Field | Value |
|---|---|
| Water recycle | ~266.67 L/min (UNIT CONVERSION ONLY: 16 m3/h stated pump flow rate -> L/min; pump run 6 h/day only, giving Qw = 96 m3/day, identical across IMTA/FRS/NFT) |
| Water volume in the system | NR (paper states individual compartment volumes only, never a stated system total; see Experimental Remarks) |
| Water type | Well water source (fresh water) (p.3) |
| Daily Water exchange rate | NR (paper states ~5% of system volume per WEEK, not a daily figure, p.4) |
| Aq pH | 7.44 +/- 0.54 |
| pHOptimal | ~7.0 (target/control setpoint; freshwater added when sedimentation-pond pH exceeded 8.0, to bring it back toward 7.0, p.11-12) |
| Dissolved Oxigen | 5.99 +/- 1.12 (ppm; UNIT CONVERSION ONLY: mg/L reported, numerically equal to ppm in freshwater; Table 1, IMTA-FRS outflow, second cycle) |
| EC | 708.17 +/- 5.67 (dS/m; UNIT CONVERSION ONLY: mS/cm reported, numerically equal to dS/m; Table 1, IMTA-FRS outflow, second cycle) |
| Water temperature | 24.7-29.1 (range only, no trial mean reported, aquatic animal ponds generally, not split by system, Results p.7); Discussion p.9 separately states 24-28 range for fish ponds — both ranges recorded, see Extraction notes |
| TAN / NH4-N | 0.29491 +/- 0.00533 (mg/L; UNIT CONVERSION ONLY: 294.91 +/- 5.33 ug/L -> mg/L; paper reports NH3 not TAN specifically, Table 1, IMTA-FRS outflow, second cycle) |
| NO2-N | 0.05845 +/- 0.00145 (mg/L; UNIT CONVERSION ONLY: 58.45 +/- 1.45 ug/L -> mg/L; standard-convention reading of Table 1’s ‘NO2’ row, see WARN-MATERIAL in Extraction notes; IMTA-FRS outflow, second cycle) |
| NO3-N | 0.32021 +/- 0.00363 (mg/L; UNIT CONVERSION ONLY: 320.21 +/- 3.63 ug/L -> mg/L; standard-convention reading of Table 1’s ‘NO3’ row; IMTA-FRS outflow, second cycle) |
Plant
| Field | Value |
|---|---|
| Plant | Multiple vegetable species (see Details) — bell pepper, chili pepper, eggplant, red leaf lettuce, green leaf lettuce, head lettuce, tomato, cucumber, broccoli |
| Details | IMTA-FRS second-cycle total harvest (kg), Table 2: Bell pepper 148.60; Chili pepper 99.40; Eggplant 118.23; Red leaf lettuce 35.20; Green leaf lettuce 37.60; Head lettuce 62.40; Tomato 256.68; Cucumber 184.00; Broccoli 48.20. Grown in Styrofoam rafts, 20 rafts of 1 m2 each (25 holes/raft, 2-inch), 72 plants/raft (cucumber, broccoli, eggplant) or 96 plants/raft (pepper, lettuce, tomato) (p.4). All plants ‘grew positively… with no symptoms of nutritional or mineral imbalance’ (p.11). |
| Plant Category | Leafy vegetables (lettuce types) + fruiting vegetables (pepper, eggplant, tomato, cucumber, broccoli) — paper’s own grouping by conductivity factor: Group 1 low/intermediate CF 10-15 uS (broccoli, lettuce, cucumber), Group 2 high CF 20-50 uS (tomato, eggplant, pepper), p.4 |
| Days Plant after transplant | 33-45 to 80-90 (range only, species-dependent, to first harvest; no single trial value reported, p.4) |
| Plants/m2 | 15 (head lettuce, IMTA-FRS, p.7; consistent figure across both mentions in text) |
| Plant fresh weight | NR (paper reports total kg per crop per plot, not g/plant; see Details) |
System & Setup
| Field | Value |
|---|---|
| System type | Floating Raft System (FRS) — Styrofoam rafts floating in a 20 m2 growing bed (20x1x0.3 m LxWxD), black plastic liner (p.4) |
| Media Details | 20 m2 growing bed, 20x1x0.3 m (LxWxD), 1mm black plastic liner, 5cm drain; 5cm-thick Styrofoam board cut to bed size, 20 rafts of 1.00 m2 each fitted with 25 holes (2 inch); plastic pots with 3cm synthetic sponge inserts (p.4) |
| Biological system already in use | Y (Sand filter + large biological filter (6 m3) downstream of sedimentation pond; ammonia oxidized to nitrite then nitrate before water reaches hydroponic units (p.3)) |
| Air supplement | Y (Closed aeration network, air nozzles throughout system; 4 air blowers (Siemens, Munich, Germany; SCHMALZ, Glatten, Germany) on 30-min automatic timers, 24h/day; aeration nozzle maintains DO >5 ppm (p.3, p.14)) |
| pH Buffers | Y (Freshwater well water manually fed into system via fish ponds when sedimentation-pond pH rose above 8.0, to bring it back to ~7.0 (p.11-12)) |
| Climate control | Y (Shade cloth and plastic sheeting over greenhouse structures for summer/winter temperature moderation (p.9-11); no active heating/cooling described) |
| Artificial Lighting | N (Plants cultivated ‘with natural photosynthesis, available radiation, and photoperiod’ (p.4); no supplemental lighting described) |
| Equipment | Self-priming pump 16 m3/h; 3 additional water pumps + manual ball valves; sand filter; biological filter 6 m3; 4 air blowers (Siemens, SCHMALZ) on 30-min timers; solar panels 4 m2 / 3 kW (08:00-16:00) + grid backup; YSI Pro Plus multiparameter probe (temperature, EC, pH, DO, TA); APHA methods for BOD/COD/NH4/NO2/NO4[sic]/PO4/TP (p.3) |
| Control Parameters | DO maintained >5 ppm via aeration; pH corrective action (freshwater addition) if sedimentation pond pH >8.0, target ~7.0; water temperature target 24-28C (seasonal, via shade cloth/plastic sheeting) (p.3, p.9-12) |
| Combination | Nile tilapia + African catfish + thin-lipped grey mullet + freshwater prawn + freshwater mussels (IMTA polyculture) coupled to Floating Raft System hydroponics growing 9 vegetable species/types |
Site
| Field | Value |
|---|---|
| Region | Africa |
| Country | Egypt |
| Average room Temperature | 25-32 (deg C, range; greenhouse air temperature during plant cultivation, p.4) |
Results & Statistics
| Field | Value |
|---|---|
| Measured Unit | kg per crop per treatment (total harvest, Table 2); plants/m2 density stated only for lettuce types (see Details/Plants per m2) |
| Statistic Details | Shapiro-Wilk and Bartlett’s tests (normality); Student’s t-test (aquatic animal growth/feed utilization/production); one-way ANOVA + Duncan’s multiple range test p<=0.05 (plant production, nutrient removal); 5% significance level; SPSS v.17.0 (p.6) |
| Statistically analysed | Y |
| Replicates (n) | 3 (analytical sub-sample replicate for growth/proximate composition, Table 3-5 footnotes); system-level replication NR — each of IMTA/IMTA-FRS/IMTA-NFT appears to be a single pond/trough set, not spatially replicated |
| AP | NR (see Extraction notes — no single per-m2 yield figure comparable across the multi-species treatment; full breakdown in Details) |
| HYD | NA (no hydroponic-only control arm in this study) |
Experimental Remarks: TRIAL DEFINITION: T1 = IMTA-FRS, HLR 4.8 m/day (Qw 96 m3/day / 20 m2 FRS bed), second production cycle (147 days). No hydroponic-only or fish-only paired control exists in this design; the ‘IMTA’ column (fish/prawn/mussel ponds only, no hydroponics, HLR 2.4 m/day) is the closest comparator, reported in Table 2 but not extracted as its own trial row per SCHEMA.md (not an aquaponic treatment). Aquaculture-side data (fish/mullet/prawn/mussel growth, feed, N/P balance) is IDENTICAL between the FRS and NFT configurations per Tables 3-4-6-7 (same numbers reported under both column headers) — only the plant/hydroponic-side data differs between T1 and T2. | WARN-BLOCK Fish biomass created: see Extraction notes in the note file; UNCLEAR recorded, four irreconcilable candidate figures (736.46/868.83 kg system total; 145.49/157.12 kg tilapia; 271.01/323.00 kg catfish). | WARN-MATERIAL NO2-N/NO3-N: Table 1 footnote ‘NO2 nitrate, NO3 nitrite’ contradicts row labels and body-text usage; standard convention used instead (see note file). | Per-species full data (Tables 3-5, second cycle): Mullet IBW 5.3 +/- 0.01 g, FBW 117.34 +/- 1.69 g; Prawn IBW 0.20 +/- 0.01 g, FBW 25.89 +/- 0.56 g; Mussels IBW 125.34 +/- 13.40 g, FBW 487.14 +/- 26.1 g. Proximate composition (DM/CP/EE/ash %, GE KJ/kg), second cycle: Tilapia 27.87/58.53/27.58/13.89/591.33; Catfish 29.08/60.40/26.57/13.03/573.45; Mullet 31.16/56.79/25.64/17.57/551.86; Prawn 27.92/51.45/9.52/39.03/408.91; Mussels 14.48/39.84/7.37/52.79/294.74 (Table 5). | Dietary N efficiency progression (NO COLUMN, central finding): 44.40% (tilapia+catfish) -> 59.06% (+mullet/prawn) -> 65.61% (+mussels) -> 83.51% (+FRS, this trial) [Fig. 3A, Table 6]. Dietary P efficiency: 40.46% -> 51.19% -> 54.67% -> 96.82% (Abstract/Discussion) / 96.81% (Conclusion) (+FRS, this trial) [Fig. 4A, Table 7] — WARN-MINOR, 96.82 vs 96.81 within rounding, no cell affected. | Water quality NOT extracted for lack of column (Table 1, IMTA-FRS outflow, second cycle): BOD 3.88 +/- 1.09 mg/L; COD 6.99 +/- 0.57 mg/L; TA 284.65 +/- 4.73 mg/L; TSS 22.58 +/- 1.56 mg/L; PO4 72.68 +/- 1.04 ug/L; TP 140.15 +/- 2.54 ug/L. | Water volume components stated individually, not summed (no derivation): 5x 40 m3 ponds (tilapia, catfish, mullet+prawn, mussels, sedimentation) = 200 m3; biological filter 6 m3; sump 3 m3; FRS bed 20 m3 (T1 only); NFT trough volume not stated. | UNIT CONVERSION ONLY: pump flow 16 m3/h -> 266.67 L/min; EC mS/cm -> dS/m (1:1, no numeric change); DO mg/L -> ppm (1:1, no numeric change); NH3/NO2/NO3 ug/L -> mg/L (/1000). | NOT DERIVED, left NR: Initial Stock density (kg/m3) — paper gives 15 fish/m3 tilapia, 10 fish/m3 catfish, 50 fry/m3 mullet, 84 prawn/m2, 2.5 kg/m2 mussels, none convertible to kg/m3 without multiplying by unstated mean individual weight at stocking; N/P/K feed % composition — only absolute kg given (25.70 kg N, 9.70 kg P in 571.90 kg feed); Water volume total; Daily Water exchange rate (only a weekly ~5% figure given); FUE AP/HYD; WUE. | Statistical design caveat (not a contradiction, an interpretation note): no system-level replication is described; the letter-based significance testing in Tables 3-5 compares first vs second production cycle within each species, not spatial treatment replicates.
godaOptimizingNutrientUtilization2024-T2
Fish
| Field | Value |
|---|---|
| Fish | Nile tilapia (Oreochromis niloticus); African catfish (Clarias gariepinus); Thin-lipped grey mullet (Liza ramada); Freshwater prawn (Macrobrachium rosenbergii); Freshwater mussels (Aspatharia chaiziana, A. marnoi) — IMTA polyculture, identical aquaculture chain feeding both FRS and NFT hydroponic units |
| FCR | System cumulative FCR (stated) = 0.90 (see Extraction notes, not flagged as contradiction but does not reconcile with a simple feed/biomass recompute); per-species second cycle (Table 4): Tilapia 1.28 +/- 0.11, Catfish 1.42 +/- 0.24 (measured); Mullet 1.24, Prawn 1.21, Mussels 0.90 (estimate values per footnote) |
| SGR | Tilapia 1.77 +/- 0.30 %/day; Catfish 1.24 +/- 0.22; Mullet 2.11 +/- 0.17; Prawn 3.31 +/- 0.32; Mussels 0.92 +/- 0.42 (second cycle, Table 3) |
| Protein | 30.58 (crude protein %, diet fed to tilapia and catfish; ambiguous ‘respectively’ pairing in text, see Extraction notes) |
| Fish size initial | Tilapia 20.4 +/- 1.70 g; Catfish 131.27 +/- 7.60 g (IBW, second cycle, Table 3; conflicts with Methods-stated 25.4 +/- 1.7 g / 173.27 +/- 5.64 g, see Extraction notes) |
| Fish size final | Tilapia 275.65 +/- 2.14 g; Catfish 815.65 +/- 8.20 g (FBW, second cycle, Table 3) |
| Feed routine | Quantity of feed consumed daily adjusted based on periodic weighings; initial sampling day 30 post-stocking, then every 15 days (p.4) |
| Feed regime | Experimental diet, 30.58% crude protein / 19.38 MJ gross energy per kg (p.4); 2-week pre-trial acclimation on same diet |
| Total Feed (kg) | 571.90 (tilapia + catfish combined, second cycle, stated Abstract/Results); Tilapia 186.05 kg, Catfish 385.85 kg (Table 6, per 40 m3 pond) |
| Fish biomass created (kg) | UNCLEAR — see Extraction notes WARN-BLOCK. Candidates: Total IMTA = 736.46 kg (Abstract/Results p.9) vs 868.83 kg (Table 2, IMTA column, second cycle); Tilapia = 145.49 kg (Abstract ‘monoculture’, also reused as IMTA-internal gain in N-balance section p.9) vs 157.12 kg (Table 2); Catfish = 271.01 kg (same dual use) vs 323.00 kg (Table 2) |
| Fish survival rate | Tilapia 95% (estimate); Catfish 99% (estimate); Mullet 51% (estimate); Prawn 27% (estimate); Mussels 66% (estimate) (second cycle, Table 3 ‘S’ column, footnoted as estimate values) |
| Fish weight gain | Tilapia 255.25 +/- 1.73 g/fish; Catfish 684.38 +/- 8.10 g/fish; Mullet 112.04 +/- 1.70 g/animal; Prawn 25.69 +/- 0.61 g/animal; Mussels 361.8 +/- 36.20 g/animal (second cycle, Table 3) |
| Fish trial duration (days) | 147 |
Water
| Field | Value |
|---|---|
| Water recycle | ~266.67 L/min (UNIT CONVERSION ONLY: 16 m3/h stated pump flow rate -> L/min; pump run 6 h/day only, giving Qw = 96 m3/day, identical across IMTA/FRS/NFT) |
| Water volume in the system | NR (paper states individual compartment volumes only, never a stated system total; see Experimental Remarks) |
| Water type | Well water source (fresh water) (p.3) |
| Daily Water exchange rate | NR (paper states ~5% of system volume per WEEK, not a daily figure, p.4) |
| Aq pH | 8.51 +/- 0.65 |
| pHOptimal | ~7.0 (target/control setpoint; freshwater added when sedimentation-pond pH exceeded 8.0, to bring it back toward 7.0, p.11-12) |
| Dissolved Oxigen | 6.47 +/- 0.90 (ppm; UNIT CONVERSION ONLY: mg/L reported, numerically equal to ppm in freshwater; Table 1, IMTA-NFT outflow, second cycle) |
| EC | 710.34 +/- 11.45 (dS/m; UNIT CONVERSION ONLY: mS/cm reported, numerically equal to dS/m; Table 1, IMTA-NFT outflow, second cycle) |
| Water temperature | 24.7-29.1 (range only, no trial mean reported, aquatic animal ponds generally, not split by system, Results p.7); Discussion p.9 separately states 24-28 range for fish ponds — both ranges recorded, see Extraction notes |
| TAN / NH4-N | 0.20929 +/- 0.01076 (mg/L; UNIT CONVERSION ONLY: 209.29 +/- 10.76 ug/L -> mg/L; NH3, Table 1, IMTA-NFT outflow, second cycle) |
| NO2-N | 0.03342 +/- 0.00104 (mg/L; UNIT CONVERSION ONLY: 33.42 +/- 1.04 ug/L -> mg/L; standard-convention reading, see WARN-MATERIAL in Extraction notes; IMTA-NFT outflow, second cycle) |
| NO3-N | 0.34561 +/- 0.00445 (mg/L; UNIT CONVERSION ONLY: 345.61 +/- 4.45 ug/L -> mg/L; IMTA-NFT outflow, second cycle) |
Plant
| Field | Value |
|---|---|
| Plant | Multiple vegetable species (see Details) — red leaf lettuce, green leaf lettuce, head lettuce only |
| Details | IMTA-NFT second-cycle total harvest (kg), Table 2: Red leaf lettuce 82.22; Green leaf lettuce 89.54; Head lettuce 132.98. Only lettuce species were grown successfully in IMTA-NFT per Discussion (p.14): ‘broccoli, tomato, cucumber, and eggplant acclimated quickly… in IMTA-FRS systems but not in IMTA-NFT systems, but lettuce species adapted well… in all experimental conditions.‘ |
| Plant Category | Leafy vegetables (lettuce types only) — Group 1 low/intermediate CF, p.4 |
| Days Plant after transplant | 33-45 to 80-90 (range only, species-dependent, to first harvest; no single trial value reported, p.4) |
| Plants/m2 | UNCLEAR (see WARN-CHECK, Extraction notes — NFT lettuce density stated as both 3 plants/m [linear] and 3 plants/m2 [areal] in adjacent sentences, p.7, no reconciling statement) |
| Plant fresh weight | NR (paper reports total kg per crop per plot, not g/plant; see Details) |
System & Setup
| Field | Value |
|---|---|
| System type | Nutrient Film Technique (NFT) — two 122 m channels, PVC pipes with 4-5cm holes for net pots (p.3-4) |
| Media Details | Two NFT channels, 122 m each, drilled with 4-5cm diameter holes for net pots; plastic cups as planting containers, bottom perforated 30mm (p.3-4) |
| Biological system already in use | Y (Sand filter + large biological filter (6 m3) downstream of sedimentation pond; ammonia oxidized to nitrite then nitrate before water reaches hydroponic units (p.3)) |
| Air supplement | Y (Closed aeration network, air nozzles throughout system; 4 air blowers (Siemens, Munich, Germany; SCHMALZ, Glatten, Germany) on 30-min automatic timers, 24h/day; aeration nozzle maintains DO >5 ppm (p.3, p.14)) |
| pH Buffers | Y (Freshwater well water manually fed into system via fish ponds when sedimentation-pond pH rose above 8.0, to bring it back to ~7.0 (p.11-12)) |
| Climate control | Y (Shade cloth and plastic sheeting over greenhouse structures for summer/winter temperature moderation (p.9-11); no active heating/cooling described) |
| Artificial Lighting | N (Plants cultivated ‘with natural photosynthesis, available radiation, and photoperiod’ (p.4); no supplemental lighting described) |
| Equipment | Self-priming pump 16 m3/h; 3 additional water pumps + manual ball valves; sand filter; biological filter 6 m3; 4 air blowers (Siemens, SCHMALZ) on 30-min timers; solar panels 4 m2 / 3 kW (08:00-16:00) + grid backup; YSI Pro Plus multiparameter probe (temperature, EC, pH, DO, TA); APHA methods for BOD/COD/NH4/NO2/NO4[sic]/PO4/TP (p.3) |
| Control Parameters | DO maintained >5 ppm via aeration; pH corrective action (freshwater addition) if sedimentation pond pH >8.0, target ~7.0; water temperature target 24-28C (seasonal, via shade cloth/plastic sheeting) (p.3, p.9-12) |
| Combination | Nile tilapia + African catfish + thin-lipped grey mullet + freshwater prawn + freshwater mussels (IMTA polyculture) coupled to Nutrient Film Technique hydroponics growing 3 lettuce types |
Site
| Field | Value |
|---|---|
| Region | Africa |
| Country | Egypt |
| Average room Temperature | 25-32 (deg C, range; greenhouse air temperature during plant cultivation, p.4) |
Results & Statistics
| Field | Value |
|---|---|
| Measured Unit | kg per crop per treatment (total harvest, Table 2); plants/m2 density stated only for lettuce types (see Details/Plants per m2) |
| Statistic Details | Shapiro-Wilk and Bartlett’s tests (normality); Student’s t-test (aquatic animal growth/feed utilization/production); one-way ANOVA + Duncan’s multiple range test p<=0.05 (plant production, nutrient removal); 5% significance level; SPSS v.17.0 (p.6) |
| Statistically analysed | Y |
| Replicates (n) | 3 (analytical sub-sample replicate for growth/proximate composition, Table 3-5 footnotes); system-level replication NR — each of IMTA/IMTA-FRS/IMTA-NFT appears to be a single pond/trough set, not spatially replicated |
| AP | NR (see Extraction notes — no single per-m2 yield figure comparable across the multi-species treatment; full breakdown in Details) |
| HYD | NA (no hydroponic-only control arm in this study) |
Experimental Remarks: TRIAL DEFINITION: T2 = IMTA-NFT, HLR 6.4 m/day (Qw 96 m3/day / trough length; Table 1 states 122# m [footnoted ‘total area by m’] as the NFT trough length, matching Methods’ ‘two NFT hydroponic units (122 m each)’ and Results’ ‘IMTA-NFT (122 m)’ — stated 3x consistently. Table 2 separately lists NFT ‘Total area (m)’ = 15, which numerically equals a nearby plant-density figure and appears to be a copy/mislabel — WARN-MINOR, no dedicated column affected, see note file), second production cycle (147 days). Paired comparator is the same shared IMTA aquaculture chain used for T1 (see T1 remarks); aquaculture-side data is identical between T1 and T2 per Tables 3-4-6-7. | WARN-BLOCK Fish biomass created: same four-way irreconcilable figures as T1 (see note file). | WARN-MATERIAL NO2-N/NO3-N: same Table 1 footnote swap as T1, standard convention applied. | WARN-CHECK Plants/m2: NFT lettuce density stated as ‘3 plants m-1’ (linear, for head lettuce, p.7) and separately as ‘3 plant m-2’ (areal, for red/green leaf lettuce, same page, a few sentences later) — same numeral, incompatible units, no reconciling statement or channel width given to convert between them. Recorded UNCLEAR. Added to REVIEW.md. | Dietary N efficiency for this trial’s hydroponic addition: 65.61% (+mussels, shared baseline) -> 74.29% (+NFT) [Fig. 3B, Table 6]. Dietary P efficiency: 54.67% -> 79.81% (+NFT) [Fig. 4B, Table 7]. | Discussion (p.14) states fruiting/high-nutrient-demand crops (tomato, pepper, cucumber, eggplant, broccoli) performed poorly or were not grown in IMTA-NFT, while lettuce types ‘adapted well… in all experimental conditions’ — consistent with Table 2 showing zero production (’-’) for all non-lettuce crops under IMTA-NFT. | Water quality NOT extracted for lack of column (Table 1, IMTA-NFT outflow, second cycle): BOD 4.71 +/- 0.91 mg/L; COD 6.78 +/- 0.87 mg/L; TA 271.94 +/- 5.12 mg/L; TSS 13.7 +/- 1.22 mg/L; PO4 72.96 +/- 1.54 ug/L; TP 147.46 +/- 3.34 ug/L. | UNIT CONVERSION ONLY: pump flow 16 m3/h -> 266.67 L/min (same system-wide flow as T1); EC mS/cm -> dS/m; DO mg/L -> ppm; NH3/NO2/NO3 ug/L -> mg/L (/1000). | NOT DERIVED, left NR: same list as T1 (Initial Stock density, N/P/K %, Water volume total, Daily Water exchange rate, FUE AP/HYD, WUE). | Same statistical design caveat as T1 (no system-level replication; letters compare cycle-to-cycle).