Effects of Crayfish Aquaponics System on Growth and Yield of Leafy Vegetables
Metadata
- Cite key: monroeEffectsCrayfishAquaponics2015
- Item type: Journal Article (per Zotero metadata) — but see note below
- Authors: A. Monroe, M. Day, M. Pfister, A. Saha, S. Saha
- Affiliation: Department of Biology and Department of Chemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
- Journal: [not reported]
- Date: 11/2015
- Date added: 2021-06-27
- DOI: [not reported] — no DOI found in the PDF or in
zotero-export.csv - Funding: Georgia Southern University’s College of Undergraduate Research
- URL: [not reported]
- PDF:
Monroe et al. - Effects of Crayfish Aquaponics System on Growth an.pdf
Opinion
A single-page undergraduate research poster, not a peer-reviewed journal article — despite Zotero’s item type of “Journal Article,” the Publication Title field is empty and the Zotero page count is 1. It reports a real RCBD experiment (3 blocks, AP vs HYD, two lettuce cultivars) but almost all quantitative results (fresh weight, height, chlorophyll index) exist only as bar-chart heights with no accompanying numbers in text or tables, and no test name, software, or p-values are ever given. Useful as a small, transparent negative/mixed result (no significant AP vs HYD difference in biomass, height, or chlorophyll) but not citable for any specific magnitude.
Abstract
Aquaponics is an agricultural production system in which the waste produced by aquatic animals, such as fish, provides nutrients for plants. Bacteria in the water convert ammonium from the animal waste into nitrites and then nitrates that plants can use for nourishment. An aquaponics study was conducted at a climate controlled greenhouse at Georgia Southern University, Statesboro, GA, where romaine and green leaf lettuce were used as agricultural crops. Red crayfishes and white river crayfishes were used as the aquatic species. The objectives of the study were to understand and compare the effects of a crayfish aquaponics system and hydroponic (no crayfish) on the growth, vigor and yield of leafy vegetable crops. Six tanks were used to create 12 floating plots of green leaf and romaine combinations. Five of each variety of lettuce were placed on each plot. Randomized complete block design was used to layout the plots. The seedlings were planted in coconut coir and vermiculite and placed in the holes of floating polystyrene sheets, allowing the roots to remain submerged in the water. Each tank housed twelve crayfishes. Crayfish are territorial, so hiding places were provided in the tank to lower the risk of injury and/or mortality in the tanks. The crayfishes were observed throughout the experiment to determine if they can maintain relatively stable populations that will provide enough nutrients for the vegetables. FloraNova Grow (7-4-10) Hydroponic Nutrient Solution was applied to all tanks (355 mL per tank) as a basic nutrient source. The tanks were monitored for water quality to ensure there was a balance between waste production and water/nutrient filtration. It was determined that no significance between aquaponics and hydroponics occurred for chlorophyll index, plant biomass, and plant height. However, romaine lettuce experienced greater chlorophyll index than green leaf. Green leaf lettuce produced higher biomass and length.
Summary
Undergraduate researchers at Georgia Southern University ran a randomized complete block design (3 blocks, 6 tanks) comparing a crayfish aquaponics system against a no-crayfish hydroponic control, growing romaine and green leaf lettuce on floating polystyrene rafts in coconut coir/vermiculite plugs. Each tank held twelve crayfish (red crayfish and white river crayfish, common names only), and a small dose of a commercial hydroponic nutrient solution (FloraNova Grow 7-4-10) was added to every tank regardless of treatment. They measured chlorophyll index (SPAD meter), plant height, and plant fresh weight/biomass, and tracked weekly pH, ammonia, nitrite, and nitrate in both treatments for 11 weeks. They found no statistically significant difference between aquaponics and hydroponics for chlorophyll index, biomass, or height, though there were non-significant numerical trends toward aquaponics producing taller, heavier plants. Between the two lettuce cultivars, green leaf lettuce had significantly higher fresh weight than romaine, while romaine had higher chlorophyll index. The poster reports only qualitative significance outcomes and bar-chart figures — no numeric means, SDs, test statistics, or p-values are given in the text for any of the growth measurements.
Experiment data
- Location: Climate-controlled greenhouse, Georgia Southern University, Statesboro, Georgia, USA
- Design: Randomized complete block design (RCBD); 3 blocks x 2 treatments (aquaponics with crayfish / hydroponics without crayfish) x 2 lettuce varieties (romaine, green leaf) = 6 tanks, 12 floating plots, 5 plants/plot
- Replicates / n: 3 blocks per treatment per lettuce variety (one plot per block); 5 plants per plot
- Duration: [not reported] as an explicit total; water-quality table (Table 1) spans through “Week 11” — see Extraction notes
- Organisms: Crayfish (red crayfish, white river crayfish — common names only, no scientific name given) / Lettuce (romaine, green leaf — no scientific name given)
- Statistics: Significance testing implied throughout Results/Discussion (“statistically significant” / “no statistical significance”); no test name, software, or p-values stated
- Chlorophyll index, plant height, plant biomass (AP vs HYD): no significant difference (Abstract, Results) — values shown only as bar-chart heights in Figures 3–5, no numbers in text/tables
- Green leaf vs romaine fresh weight: green leaf significantly higher (Results) — no numeric values given
Water quality
This paper: Table 1 reports six biweekly/weekly periods (Weeks 1–2 through Week 11) of pH, ammonia, nitrite, and nitrate for both the aquaponics and hydroponics tanks, with no stated trial mean or SD for any parameter — only the raw period-by-period table. Per the vault’s water-quality rule, only a range (not a computed mean) was recorded, in the aquaponic-loop columns (Aq pH, TAN/NH4-N, NO2-N, NO3-N); the parallel hydroponic-side numbers have no dedicated column in trials.csv and are recorded as NO COLUMN items in Experimental Remarks instead.
Compared with:
- todo Rakocy et al. — typical aquaponic nitrate/ammonia ranges for comparison (not yet in vault, see Citations to chase)
Growth and yield (AP vs HYD)
This paper: No statistically significant difference between aquaponics and hydroponics for chlorophyll index, plant fresh weight/biomass, or plant height (Abstract; Results). A non-significant numerical trend favored aquaponics for both height and weight. All three variables are reported only as bar charts (Figs 3–5); no numeric means or SDs appear anywhere in the text.
Compared with:
- todo Saha, Monroe, Day 2016 — companion Georgia Southern basil aquaponics/crayfish study (same senior author, same crayfish/floating-raft system) reporting aquaponic basil outperforming hydroponic basil in height (+14%), fresh weight (+56%), and dry weight (+65%), with chlorophyll/leaf nutrients not differing — directly comparable design, worth cross-checking whether this lettuce study’s non-significant result and the basil study’s significant result reflect species differences or statistical power (lettuce study: n=3 blocks; note this is the same lab and likely overlapping crayfish system).
Lettuce cultivar comparison
This paper: Green leaf lettuce had significantly higher fresh weight than romaine; a non-significant numerical trend showed green leaf taller than romaine; romaine had higher chlorophyll index than green leaf (reversed direction from the biomass/height comparison). No numeric values given for any of these — narrative-only in Results/Discussion.
Linked claims
- Aquaponics and hydroponics can produce statistically equivalent leafy-vegetable yield
- Crayfish can serve as the aquatic species in a floating-raft aquaponics system
Citations to chase
- todo Saha, S., Monroe, A., Day, M.R. (2016) — companion crayfish-aquaponics basil study by an overlapping author team at the same institution; already in
zotero-export.csv(item 4955X868, not yet extracted as of this batch) — check whether it should be pulled into this vault as its own note/trial rows - todo Rakocy et al. — typical aquaponic water-quality benchmark ranges, referenced generically in the aquaponics literature but not cited by this paper itself; needed to contextualize Table 1’s wide nitrate range (6.67–80.00 mg/L)
Extraction notes
Contradiction:
⚠️MATERIAL Plant biomass (fresh weight) significance, AP vs HYD. Abstract (p.1): “It was determined that no significance between aquaponics and hydroponics occurred for chlorophyll index, plant biomass, and plant height.” Results (p.1, “Fresh Weight”): “There was no statistical significance observed between the aquaponics and hydroponics systems. However, there was a numerical trend.” Discussion (p.1, “Chlorophyll Content”): “The health and quality of plants between aquaponics and hydroponics did not differ unlike plant biomass” — this phrasing implies plant biomass did differ significantly between AP and HYD, contradicting the Abstract and Results statements above. Two independent, explicit, mutually consistent statements (Abstract + Results) both say “no statistical significance” for biomass; the Discussion line is a single brief aside using looser language, most likely a sloppy restatement of the “numerical trend” already noted in Results rather than a genuine second, contradictory significance finding. Recorded as “not statistically significant” for the AP vs HYD fresh-weight comparison (Statistically analysed field), per the two clearer/more detailed sources. Affects: interpretation of the (already NR, figure-only) AP/HYD yield columns and the general “Statistically analysed” framing for both trial rows. Does not affect the extracted cells themselves since no numeric fresh-weight values exist to place in AP/HYD regardless.
[unclear]:
- Overall fish/plant trial duration is never explicitly stated as a total (e.g., “the study ran for X weeks”). The only evidence is that Table 1’s water-monitoring schedule extends through a row labeled “Week 11” (six periods: Weeks 1&2, 3&4, 5&6, 7&8, 9&10, and Week 11 alone). This is suggestive of an experiment length of at least 11 weeks but is not a stated duration for either the fish or plant components, so
Fish trial duration (days)andDays Plant after transplantwere leftNRrather than inferring ~77 days from the table’s extent. - Figure 5’s y-axis is labeled “Chlorophyll Index (µg/L)” for what is described in Methods as a SPAD-502 Plus Chlorophyll Meter reading — SPAD meters normally output a unitless index, not a concentration in µg/L. Recorded as stated in the paper; not corrected, since the underlying chlorophyll values are unreadable from the figure anyway (no impact on any extracted cell).
[not reported] fields grouped:
- Fish/crayfish husbandry: Initial stock density (kg/m³), FCR, SGR, feed protein/N/P/K, % of body weight ration, feed routine/regime, total feed (kg), fish biomass created, fish survival rate, fish weight gain, fish size initial/final, fish trial duration — the poster gives crayfish count per tank (12) and general housing/behavior notes only, no feeding or growth data of any kind for the crayfish themselves.
- Water system infrastructure: Water recycle rate, water volume in the system, water type, water classification, daily water exchange rate, dissolved oxygen, EC, water temperature, average room temperature, lat/long, pHOptimal, FUE AP/HYD, WUE.
- Plant growth numerics: Days plant after transplant, plants/m², SPAD value, plant height, leaf count, plant fresh weight, plant dry matter, tissue nitrate AP/HYD — all either not measured (leaf count, tissue nitrate, dry matter) or shown only as unlabeled bar-chart heights with no numeric value in text or table (SPAD, height, fresh weight — Figs 3–5).
- Design/management flags: Biological system already in use, air supplement, iron supplemented, remineralization, pH buffers, artificial lighting — none mentioned at all.
NO COLUMN items (in Experimental Remarks of both trial rows):
- Hydroponic-side water quality from Table 1 (no dedicated HYD water-quality columns exist in the schema): pH range 6.24–8.17; Ammonia range 0.00–8.00 mg/L; Nitrite range 0.00–5.00 mg/L; Nitrate range 0.00–80.00 mg/L (all range-only, no trial mean reported, Weeks 1–11).
- “12 crayfish per tank” population count (no tank volume given, so no stocking density could be computed or recorded).
Scanned/OCR status: PDF has a native text layer (not scanned); ligature-substitution artifacts (e.g., “produc1on” for “production,” “leAuce” for “lettuce”) were present and corrected only in the Abstract transcription above for readability — content/wording unchanged. Not routed to NEEDS_OCR.md.
Type judgment: Classified experiment — the authors collected their own data under a randomized complete block design with defined treatments (crayfish aquaponics vs. no-crayfish hydroponics) and report significance-tested comparisons, even though the write-up is a poster rather than a full journal article and omits numeric results.
Plant/Fish category wording: Plant Category recorded as “Leafy vegetables” per the paper’s own title wording, since no more specific plant category language is used in the body text. Fish Category left NR — the paper never categorizes the crayfish beyond naming them “red crayfishes” and “white river crayfishes.”
Source: Monroe et al. - Effects of Crayfish Aquaponics System on Growth an.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
monroeEffectsCrayfishAquaponics2015-T1
Fish
| Field | Value |
|---|---|
| Fish | Red crayfish; White river crayfish (common names only, no scientific name given) |
Water
| Field | Value |
|---|---|
| Aq pH | 6.82 - 8.20 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
| TAN / NH4-N | 0.12 - 6.00 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
| NO2-N | 0.92 - 5.00 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
| NO3-N | 6.67 - 80.00 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
Plant
| Field | Value |
|---|---|
| Plant | Romaine lettuce |
| Details | One of two lettuce varieties grown in the same tanks/blocks as green leaf lettuce (T2); floating plot, 5 plants/plot; harvest timing/day not stated |
| Plant Category | Leafy vegetables (title) |
| SPAD (aquaponics) | NR (figure only - Fig. 5 bar chart, no numeric value stated in text or table) |
| Plant height | NR (figure only - Fig. 4 bar chart, no numeric value stated in text or table) |
| Plant fresh weight | NR (figure only - Fig. 3 bar chart, no numeric value stated in text or table) |
System & Setup
| Field | Value |
|---|---|
| System type | Floating raft (polystyrene sheets with holes, roots submerged in tank water) |
| Media Details | Coconut coir and vermiculite (seedling planting media in floating polystyrene sheet holes) |
| Climate control | Y (Climate controlled greenhouse at Georgia Southern University, Statesboro, GA (no specific setpoints given)) |
| Nutrient supplemented | Y (FloraNova Grow (7-4-10) Hydroponic Nutrient Solution applied to all tanks (both aquaponic and hydroponic treatments alike), 355 mL/tank, as a basic nutrient source) |
| Equipment | SPAD 502 Plus Chlorophyll Meter (chlorophyll index measurement) |
| Control Parameters | Weekly water quality monitoring for pH, ammonia, nitrite, and nitrate (Table 1); crayfish population counted 3x/week |
| Combination | Crayfish (red crayfish and white river crayfish) and romaine lettuce; aquaponics (with crayfish) vs hydroponics (no crayfish), floating raft system, RCBD with 3 blocks |
Site
| Field | Value |
|---|---|
| Region | North America |
| Country | USA |
Results & Statistics
| Field | Value |
|---|---|
| Measured Unit | g (fresh weight/biomass, Fig. 3 axis ‘Weight (g)’); mm (height, Fig. 4 axis ‘Height (mm)’); µg/L (chlorophyll index, Fig. 5 axis label - atypical unit for a SPAD meter, recorded as stated) |
| Statistic Details | Randomized complete block design (RCBD), 3 blocks; qualitative significance language used throughout Results/Discussion (‘statistically significant’ / ‘no statistical significance’); no test name, software, or p-values ever stated |
| Statistically analysed | Y |
| Replicates (n) | 3 |
| AP | NR (figure only, no numeric yield value stated in text or table) |
| HYD | NR (figure only, no numeric yield value stated in text or table) |
Experimental Remarks: TRIAL DEFINITION: T1 = romaine lettuce grown on the crayfish aquaponics treatment, paired against romaine lettuce grown on the no-crayfish hydroponic control (HYD columns) within the same RCBD. Distinguished from T2 (green leaf lettuce) by lettuce variety only - both share the same 6 tanks, 3 blocks, and crayfish system. Split into 2 trial rows because the paper reports per-cultivar results (Results ‘Lettuce Varieties’ section; Figs 3-5 break out romaine vs green leaf by block and treatment). | Replicates (n) = 3: one romaine plot per block x 3 blocks per treatment (5 plants/plot; plant count is a sub-replicate, not counted as an additional experimental unit). | WARN-MATERIAL Plant biomass (fresh weight) significance, AP vs HYD: Abstract (p.1) ‘no significance between aquaponics and hydroponics occurred for chlorophyll index, plant biomass, and plant height’; Results (p.1, ‘Fresh Weight’) ‘There was no statistical significance observed between the aquaponics and hydroponics systems. However, there was a numerical trend’; Discussion (p.1, ‘Chlorophyll Content’) ‘The health and quality of plants between aquaponics and hydroponics did not differ unlike plant biomass’ (implies plant biomass DID differ). Two explicit, mutually consistent sources (Abstract+Results) vs one brief informal Discussion aside; recorded as ‘not statistically significant’ per Abstract+Results, the clearer/more detailed sources. Discussion wording noted as likely loose restatement of the ‘numerical trend’ rather than a genuine second finding. Affects: Statistically analysed interpretation and framing of the (already NR, figure-only) AP/HYD yield cells. | [unclear] Fish/plant trial duration: never explicitly stated as a total. Table 1’s water-monitoring schedule extends through a row labeled ‘Week 11’ (periods: Weeks 1&2, 3&4, 5&6, 7&8, 9&10, and Week 11 alone), suggesting an experiment length of at least 11 weeks, but this is not a stated duration for either the fish or plant components. Left NR (Fish trial duration, Days Plant after transplant) rather than inferring ~77 days from the table’s extent. | NOT REPORTED (grouped): fish/crayfish husbandry (stock density, FCR, SGR, feed protein/N/P/K, % body weight ration, feed routine/regime, total feed, fish biomass created, survival rate, weight gain, size initial/final, trial duration - poster gives only 12 crayfish/tank and general housing notes, no feeding or growth data); water infrastructure (recycle rate, system water volume, water type/classification, daily exchange rate, dissolved oxygen, EC, water temperature, average room temperature, lat/long, pHOptimal, FUE AP/HYD, WUE); plant numerics beyond what is notable per-trial below (days after transplant, plants/m2, leaf count, tissue nitrate AP/HYD, dry matter - not measured at all); design flags (biological system already in use, air supplement, iron supplemented, remineralization, pH buffers, artificial lighting - none mentioned). | NO COLUMN: Hydroponic-side water quality from Table 1 (no dedicated HYD water-quality columns in schema): pH range 6.24-8.17; Ammonia range 0.00-8.00 mg/L; Nitrite range 0.00-5.00 mg/L; Nitrate range 0.00-80.00 mg/L (all range-only, no trial mean reported, Weeks 1-11). NO COLUMN: ‘12 crayfish per tank’ population count stated (Methods) but no tank volume given, so stocking density could not be computed or recorded.
monroeEffectsCrayfishAquaponics2015-T2
Fish
| Field | Value |
|---|---|
| Fish | Red crayfish; White river crayfish (common names only, no scientific name given) |
Water
| Field | Value |
|---|---|
| Aq pH | 6.82 - 8.20 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
| TAN / NH4-N | 0.12 - 6.00 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
| NO2-N | 0.92 - 5.00 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
| NO3-N | 6.67 - 80.00 (range only, no trial mean reported; Table 1, aquaponics rows, Weeks 1-11) |
Plant
| Field | Value |
|---|---|
| Plant | Green leaf lettuce |
| Details | One of two lettuce varieties grown in the same tanks/blocks as romaine lettuce (T1); floating plot, 5 plants/plot; harvest timing/day not stated |
| Plant Category | Leafy vegetables (title) |
| SPAD (aquaponics) | NR (figure only - Fig. 5 bar chart, no numeric value stated in text or table) |
| Plant height | NR (figure only - Fig. 4 bar chart, no numeric value stated in text or table) |
| Plant fresh weight | NR (figure only - Fig. 3 bar chart, no numeric value stated in text or table) |
System & Setup
| Field | Value |
|---|---|
| System type | Floating raft (polystyrene sheets with holes, roots submerged in tank water) |
| Media Details | Coconut coir and vermiculite (seedling planting media in floating polystyrene sheet holes) |
| Climate control | Y (Climate controlled greenhouse at Georgia Southern University, Statesboro, GA (no specific setpoints given)) |
| Nutrient supplemented | Y (FloraNova Grow (7-4-10) Hydroponic Nutrient Solution applied to all tanks (both aquaponic and hydroponic treatments alike), 355 mL/tank, as a basic nutrient source) |
| Equipment | SPAD 502 Plus Chlorophyll Meter (chlorophyll index measurement) |
| Control Parameters | Weekly water quality monitoring for pH, ammonia, nitrite, and nitrate (Table 1); crayfish population counted 3x/week |
| Combination | Crayfish (red crayfish and white river crayfish) and green leaf lettuce; aquaponics (with crayfish) vs hydroponics (no crayfish), floating raft system, RCBD with 3 blocks |
Site
| Field | Value |
|---|---|
| Region | North America |
| Country | USA |
Results & Statistics
| Field | Value |
|---|---|
| Measured Unit | g (fresh weight/biomass, Fig. 3 axis ‘Weight (g)’); mm (height, Fig. 4 axis ‘Height (mm)’); µg/L (chlorophyll index, Fig. 5 axis label - atypical unit for a SPAD meter, recorded as stated) |
| Statistic Details | Randomized complete block design (RCBD), 3 blocks; qualitative significance language used throughout Results/Discussion (‘statistically significant’ / ‘no statistical significance’); no test name, software, or p-values ever stated |
| Statistically analysed | Y |
| Replicates (n) | 3 |
| AP | NR (figure only, no numeric yield value stated in text or table) |
| HYD | NR (figure only, no numeric yield value stated in text or table) |
Experimental Remarks: TRIAL DEFINITION: T2 = green leaf lettuce grown on the crayfish aquaponics treatment, paired against green leaf lettuce grown on the no-crayfish hydroponic control (HYD columns) within the same RCBD. Distinguished from T1 (romaine lettuce) by lettuce variety only - both share the same 6 tanks, 3 blocks, and crayfish system. Split into 2 trial rows because the paper reports per-cultivar results (Results ‘Lettuce Varieties’ section; Figs 3-5 break out romaine vs green leaf by block and treatment). Green leaf fresh weight was reported significantly higher than romaine (Results, no numeric value given). | Replicates (n) = 3: one green-leaf plot per block x 3 blocks per treatment (5 plants/plot; plant count is a sub-replicate, not counted as an additional experimental unit). | WARN-MATERIAL Plant biomass (fresh weight) significance, AP vs HYD: Abstract (p.1) ‘no significance between aquaponics and hydroponics occurred for chlorophyll index, plant biomass, and plant height’; Results (p.1, ‘Fresh Weight’) ‘There was no statistical significance observed between the aquaponics and hydroponics systems. However, there was a numerical trend’; Discussion (p.1, ‘Chlorophyll Content’) ‘The health and quality of plants between aquaponics and hydroponics did not differ unlike plant biomass’ (implies plant biomass DID differ). Two explicit, mutually consistent sources (Abstract+Results) vs one brief informal Discussion aside; recorded as ‘not statistically significant’ per Abstract+Results, the clearer/more detailed sources. Discussion wording noted as likely loose restatement of the ‘numerical trend’ rather than a genuine second finding. Affects: Statistically analysed interpretation and framing of the (already NR, figure-only) AP/HYD yield cells. | [unclear] Fish/plant trial duration: never explicitly stated as a total. Table 1’s water-monitoring schedule extends through a row labeled ‘Week 11’ (periods: Weeks 1&2, 3&4, 5&6, 7&8, 9&10, and Week 11 alone), suggesting an experiment length of at least 11 weeks, but this is not a stated duration for either the fish or plant components. Left NR (Fish trial duration, Days Plant after transplant) rather than inferring ~77 days from the table’s extent. | NOT REPORTED (grouped): fish/crayfish husbandry (stock density, FCR, SGR, feed protein/N/P/K, % body weight ration, feed routine/regime, total feed, fish biomass created, survival rate, weight gain, size initial/final, trial duration - poster gives only 12 crayfish/tank and general housing notes, no feeding or growth data); water infrastructure (recycle rate, system water volume, water type/classification, daily exchange rate, dissolved oxygen, EC, water temperature, average room temperature, lat/long, pHOptimal, FUE AP/HYD, WUE); plant numerics beyond what is notable per-trial below (days after transplant, plants/m2, leaf count, tissue nitrate AP/HYD, dry matter - not measured at all); design flags (biological system already in use, air supplement, iron supplemented, remineralization, pH buffers, artificial lighting - none mentioned). | NO COLUMN: Hydroponic-side water quality from Table 1 (no dedicated HYD water-quality columns in schema): pH range 6.24-8.17; Ammonia range 0.00-8.00 mg/L; Nitrite range 0.00-5.00 mg/L; Nitrate range 0.00-80.00 mg/L (all range-only, no trial mean reported, Weeks 1-11). NO COLUMN: ‘12 crayfish per tank’ population count stated (Methods) but no tank volume given, so stocking density could not be computed or recorded.
Plant Measurements
| Trial | System | Category | Analyte | Value | Unit | Sig. | Location |
|---|---|---|---|---|---|---|---|
| monroeEffectsCrayfishAquaponics2015-T1 | AP | biochemistry | Chlorophyll index (SPAD) | NR | NR | ns | Fig. 5 (p.1) |
| monroeEffectsCrayfishAquaponics2015-T1 | HYD | biochemistry | Chlorophyll index (SPAD) | NR | NR | ns | Fig. 5 (p.1) |
| monroeEffectsCrayfishAquaponics2015-T2 | AP | biochemistry | Chlorophyll index (SPAD) | NR | NR | ns | Fig. 5 (p.1) |
| monroeEffectsCrayfishAquaponics2015-T2 | HYD | biochemistry | Chlorophyll index (SPAD) | NR | NR | ns | Fig. 5 (p.1) |