Quartz 5

Small-scale Aquaponic Food Production: Integrated Fish and Plant Farming

Properties1
tagsmeta/type/narrative-review, meta/region/global, meta/fish/tilapia, meta/fish/carp, meta/fish/catfish, meta/fish/trout

25 min read

Small-scale Aquaponic Food Production: Integrated Fish and Plant Farming

Metadata

  • Cite key: somervilleSmallscaleAquaponicFood2014
  • Item type: Book / institutional technical report — FAO Fisheries and Aquaculture Technical Paper No. 589, 262 pp. (per the document’s own citation on p. iv: “Somerville, C., Cohen, M., Pantanella, E., Stankus, A. & Lovatelli, A. 2014. Small-scale aquaponic food production. Integrated fish and plant farming. FAO Fisheries and Aquaculture Technical Paper No. 589. Rome, FAO. 262 pp.”). The PDF itself is 288 pages (front matter + 262 numbered pages + unnumbered final material).
  • Authors: Christopher Somerville (FAO Consultant, Ireland), Moti Cohen (FAO Consultant, Israel), Edoardo Pantanella (FAO Consultant, Italy), Austin Stankus (FAO Consultant, Italy), Alessandro Lovatelli (FAO Aquaculture Branch, Italy) — all per the title page (PDF p. 3).
  • Affiliation: Food and Agriculture Organization of the United Nations (FAO), Fisheries and Aquaculture Department, Rome.
  • Journal: [not applicable — institutional technical report] Published by FAO, Rome. FAO document symbol I4021E/1/08.14. ISBN 978-92-5-108532-5 (print), E-ISBN 978-92-5-108533-2 (PDF), ISSN 2070-7010 (FAO Fisheries and Aquaculture Technical Paper series).
  • Date: 2014 — per the document’s own self-citation (p. iv), the copyright notice ”© FAO, 2014” (p. iv), and the PDF’s embedded creation-date metadata (CreationDate: D:20141124, i.e. 24 November 2014). ⚠️ See Extraction notes for a year discrepancy against zotero-export.csv.
  • Date added: [not reported]
  • DOI: [no DOI found] — no DOI is printed anywhere in the PDF (checked front matter, copyright page, and every page containing the string “doi”; the only other hits were unrelated in-text uses of the word “doing” and one DOI belonging to a different cited work in Appendix 3, not to this document itself). A Crossref bibliographic search for the title also returned no DOI record for this FAO paper itself — only other papers that cite it. FAO’s institutional record for this document lives on its Open Knowledge repository (URL below) and on www.fao.org/fishery/publications/31589, neither of which lists a DOI.
  • Funding: [not reported] as a grant/award — the report was prepared as an FAO institutional technical paper; no external funder or grant number is stated (Preparation of this document, p. iii).
  • URL: https://openknowledge.fao.org/handle/20.500.14283/i4021e (FAO Open Knowledge repository record; returned HTTP 403 to automated fetching during this extraction, so its metadata could not be independently verified — recorded from web search result titles only, not confirmed by direct page read). Also listed at www.fao.org/fishery/publications/31589.
  • PDF: Somerville and Food and Agriculture Organization of the United Nations - 2015 - Small-scale aquaponic food production integrated .pdf (288 pages total)

Opinion

Scope of what was actually read, given the 262-printed-page length: This is a large, single-volume FAO practitioner manual, organised into 9 chapters plus 9 appendixes and a quick-reference handout (full Contents on PDF pp. 7–9, read in full). Read in full: the front matter (title page, disclaimer, Preparation of this document, Abstract, pp. iii–iv), Chapter 1 “Introduction to aquaponics” (pp. 1–10), Chapter 2 “Understanding aquaponics” — the nitrogen cycle and feed rate ratio (pp. 11–19), Chapter 3 “Water quality in aquaponics” — all five water-quality parameters and hardness (pp. 21–33), Chapter 6 “Plants in aquaponics” (pp. 83–102), Chapter 7 “Fish in aquaponics” (pp. 103–121), Chapter 8 “Management and troubleshooting” — including the worked feed-rate-ratio calculation and Tables 8.1–8.4 (pp. 123–139), Appendix 1 “Vegetable production guidelines for 12 common aquaponic plants” (pp. 169–182), the ammonia/biofilter-sizing worked calculation in Appendix 4 (pp. 191–193), and the cost–benefit tables in Appendix 7 (pp. 205–207). That is roughly 120 of the 262 numbered pages (about 46 percent), read in depth with contradiction-checking applied only within that material. Not read in depth, sampled only via the Contents-page headings: Chapter 4 “Design of aquaponic units” (media bed/NFT/DWC construction detail, pp. 35–73), Chapter 5 “Bacteria in aquaponics” (pp. 75–81), Chapter 9 “Additional topics” (organic fertilizers, alternative feeds, saline aquaponics, case studies, pp. 141–155), the Glossary (pp. 163–166), Appendix 2 (pest/disease control, pp. 183–186), Appendix 3 (fish disease, pp. 187–189), Appendix 5 (homemade fish feed — only its opening protein-composition section was read, pp. 193–194 partial), Appendix 6 (key considerations before setting up a system, pp. 199–203), Appendix 8 (step-by-step construction guide, pp. 209–247, ~38 pages of build instructions), and the closing “Aquaponics quick-reference handout” (pp. 249–262). No original experimental data, sample sizes, treatments, or statistical tests belonging to this document itself were found anywhere in the material read: this is a synthesis of established RAS/hydroponics engineering practice, aquaponics-specific research by others (chiefly Rakocy, Lennard, Savidov and Salam, named explicitly in the brief history section, p. 7–8), and the authors’ own practitioner experience, presented as prescriptive ranges, rules of thumb and worked design/cost examples rather than as a reported study. This matches the CLAUDE.md guidance for long book-scale PDFs and follows the same honest partial-sampling approach used for the sibling entry lennardCommercialAquaponicSystems2017 in this vault.

Abstract

This technical paper begins by introducing the concept of aquaponics, including a brief history of its development and its place within the larger category of soil-less culture and modern agriculture. It discusses the main theoretical concepts of aquaponics, including the nitrogen cycle and the nitrification process, the role of bacteria, and the concept of balancing an aquaponic unit. It then moves on to cover important considerations of water quality parameters, water testing, and water sourcing for aquaponics, as well as methods and theories of unit design, including the three main methods of aquaponic systems: media beds, nutrient film technique, and deep water culture.

The publication discusses in detail the three groups of living organisms (bacteria, plants and fish) that make up the aquaponic ecosystem. It also presents management strategies and troubleshooting practices, as well as related topics, specifically highlighting local and sustainable sources of aquaponic inputs.

The publication also includes nine appendixes that present other key topics: ideal conditions for common plants grown in aquaponics; chemical and biological controls of common pests and diseases including a compatible planting guide; common fish diseases and related symptoms, causes and remedies; tools to calculate the ammonia produced and biofiltration media required for a certain fish stocking density and amount of fish feed added; production of homemade fish feed; guidelines and considerations for establishing aquaponic units; a cost–benefit analysis of a small-scale, media bed aquaponic unit; a comprehensive guide to building small-scale versions of each of the three aquaponic methods; and a brief summary of this publication designed as a supplemental handout for outreach, extension and education.

Summary

This is FAO Fisheries and Aquaculture Technical Paper No. 589, a 262-page practitioner manual written by five FAO consultants/staff as a general-audience bridge between aquaculture and hydroponics practitioners who each previously knew only their own half of aquaponics. Rather than reporting a new study, it synthesises established recirculating-aquaculture and hydroponics engineering knowledge, aquaponics-specific research from named specialists (James Rakocy/UVI, Wilson Lennard, Nick Savidov, Mohammad Abdus Salam), and the authors’ hands-on practitioner experience into prescriptive guidance covering: what aquaponics is, its history, and where it is and is not appropriate (Ch. 1); the nitrogen cycle, nitrifying bacteria, and the “feed rate ratio” (grams of daily fish feed per m² of growing space) used to balance a unit (Ch. 2); the five key water-quality parameters — dissolved oxygen, pH, temperature, total nitrogen (ammonia/nitrite/nitrate), and hardness — with stated tolerance ranges for fish, plants and bacteria plus a “compromise” range for running all three together (Ch. 3); construction of media bed, nutrient film technique (NFT) and deep water culture (DWC) systems (Ch. 4, sampled only); bacterial biofiltration and system cycling (Ch. 5, sampled only); plant biology, nutrient deficiencies, and pest/disease management specific to a system where synthetic chemical pesticides cannot be used (Ch. 6); fish anatomy, feed conversion ratio, water-quality tolerances and species profiles for seven commercial species (Ch. 7); a worked numerical example of the feed-rate-ratio design calculation, fish-stocking-density and biofilter-sizing rules of thumb, staggered-stocking tables, and a troubleshooting table (Ch. 8); and supplementary topics including organic fertilizer alternatives, alternative fish feeds, and small-scale case studies (Ch. 9, sampled only). The nine appendixes add a 12-plant growing-condition reference table, pest/disease control tables, a step-by-step ammonia/biofilter-media sizing calculation, a homemade-fish-feed guide, a pre-setup checklist, a cost–benefit worked example for a domestic-scale unit, and full construction instructions for all three system types. Throughout, the document presents ranges and rules of thumb as prescriptive guidance rather than as data from a controlled study of its own; the closest things to “results” in the document are worked arithmetic examples (the feed-rate-ratio calculation, the ammonia/biofilter sizing calculation, and the cost–benefit tables) built from the stated ranges and assumptions, not from measured trial data.

Review scope

  • Region / system covered: Global in subject matter and intended audience (the document explicitly targets “agriculture extension agents, aquaculture officers, non-governmental organizations, community organizers, companies and individuals — worldwide,” p. iii). Illustrative examples and case studies cited are drawn from multiple regions (United States of America, Australia, Canada, Bangladesh, the West Bank and Gaza Strip, and others named in Section 1.6.4’s list of humanitarian/food-security deployments: Barbados, Brazil, Botswana, Ethiopia, Ghana, Guatemala, Haiti, India, Jamaica, Malaysia, Mexico, Nigeria, Panama, the Philippines, Thailand, Zimbabwe).
  • Argument: Aquaponics is a viable, water- and land-efficient food production technique — combining two individually mature technologies (RAS aquaculture and hydroponics) — that is best suited to small-scale/domestic and educational/humanitarian applications and to locations where water is scarce, arable land is unavailable or degraded, or soil-based agriculture is otherwise difficult; it is not a wholesale replacement for soil agriculture, requires substantial technical knowledge, daily management and reliable electricity, and commercial-scale aquaponics remains comparatively rare and higher-risk than the small-scale/domestic applications the manual focuses on (Box 1, p. 5–6; Section 1.6.2, p. 8).
  • Evidence base: Practitioner/institutional synthesis: established RAS and hydroponics engineering principles, aquaponics-specific prior research attributed by name to James Rakocy (University of the Virgin Islands, UVI model), Wilson Lennard (Australia), Nick Savidov (Alberta, Canada — cited for a two-year study showing superior tomato/cucumber production under adequate nutrient levels) and Mohammad Abdus Salam (Bangladesh Agricultural University, home-scale subsistence aquaponics) (Section 1.5, p. 7–8), plus the authors’ own consulting/field experience. No systematic review methodology (search string, databases, inclusion criteria) is stated anywhere in the material read; this is consistent with narrative-review rather than systematic-review. One explicit external citation was noted for a non-aquaponics table: Table 6.2 (nutrient effects on fungal disease) is sourced “Agrios (2004)” (p. 100).
  • Frameworks/tools introduced: The feed rate ratio (grams of daily fish feed per m² of plant growing area — 40–50 g/m²/day for leafy greens, 50–80 g/m²/day for fruiting vegetables) as the single simplified balancing metric for an aquaponic unit (Section 2.4.2, p. 17–18; worked example Section 8.1.1, p. 123–124); a maximum fish stocking density rule of thumb (10–20 kg fish per 1 000 litres of water, never exceeding 20 kg/1 000 L); biofilter media-volume sizing ratios (1 litre of volcanic tuff or 0.5 litre of Bioballs® per gram of daily feed, Section 8.1.3, refined into a full worked ammonia-mass-balance calculation with a table of nine biofilter media types in Appendix 4); a “compromise” water-quality target table (Table 3.2: temp 18–30 °C, pH 6–7, ammonia <1 mg/L, nitrite <1 mg/L, nitrate 5–150 mg/L, DO >5 mg/L) balancing the separately-stated tolerance ranges of fish, plants and bacteria (Table 3.1); and a practical system-design lookup table (Table 8.1) scaling fish-tank volume, feed rate, pump flow, filter volume and plant growing area together for six unit sizes from 200 to 3 000 litres.
  • Key figures cited, own vs. secondary: Nearly all quantitative ranges in the document (water-quality tolerances, feed rates, stocking densities, biofilter sizing ratios) are presented as the manual’s own synthesized/recommended guidance rather than attributed to a single external source, so they are not marked [secondary] individually — they read as FAO’s own consolidated practitioner recommendation, drawing on the field generally. The exceptions found in the material read: the nutrient/fungal-disease-prevention table (Table 6.2) is explicitly [secondary, cites Agrios 2004] (p. 100); the claim that North Carolina State University’s early aquaponic systems used “just 5 percent” of the water used in pond culture for tilapia is attributed to that institution’s own demonstration, not measured by this manual (Section 1.5, p. 7) — [secondary, cites unnamed NCSU aquaponics research, not individually identified in the text]; and Nick Savidov’s two-year Alberta study showing “significantly superior production of tomatoes and cucumbers when some key nutrient levels were met” is explicitly attributed to Savidov’s own research, not this manual’s (Section 1.5, p. 7–8) — [secondary, cites Savidov, not individually referenced with a full citation in the pages read].

The nitrogen cycle and balancing an aquaponic unit (Ch. 2)

This document’s account: Fish waste (mostly ammonia, NH₃) is converted by two groups of nitrifying bacteria — ammonia-oxidizing bacteria (AOB, e.g. Nitrosomonas spp., optimal pH 7.2–7.8) and nitrite-oxidizing bacteria (NOB, e.g. Nitrobacter spp., optimal pH 7.2–8.2) — first to nitrite then to nitrate, the form plants use most readily (Section 2.1.1–2.2, Table 2.1, p. 11–16). Bacterial tolerance ranges are stated as 17–34 °C, pH 6–8.5, ammonia <3 mg/L, nitrite <3 mg/L, nitrate <400 mg/L, DO 4–8 mg/L (Table 2.1); below 17 °C bacterial productivity decreases, and below 10 °C productivity “can be reduced by 50 percent or more” (Section 2.3.3, p. 15). The feed rate ratio — grams of daily fish feed per m² of plant growing area — is presented as the single simplified balancing metric, assuming an industry-standard 32-percent-protein feed: 40–50 g/m²/day for leafy greens, 50–80 g/m²/day for fruiting vegetables (Box 2, p. 17–18; restated Ch. 8). Nitrogen-testing thresholds for rebalancing: if ammonia or nitrite exceed 1 mg/L, biofiltration is inadequate; if nitrate stays below 10 mg/L for several weeks, feed rate can be cautiously increased; if nitrate exceeds 150 mg/L for several weeks, partial water exchange is recommended (Section 2.4.4, p. 18–19).

The five water-quality parameters (Ch. 3)

This document’s account: Table 3.1 gives separate tolerance ranges for warm-water fish, cold-water fish, plants and bacteria across temperature, pH, ammonia, nitrite, nitrate and DO; Table 3.2 gives the “ideal compromise” for running all three organism groups together: temperature 18–30 °C, pH 6–7, ammonia <1 mg/L, nitrite <1 mg/L, nitrate 5–150 mg/L, DO >5 mg/L (p. 22). Individual parameter detail: optimum DO for all three organisms is 5–8 mg/L, with some fish (carp, tilapia) tolerating as low as 2–3 mg/L (Section 3.2.1); pH 6.0–6.5 gives full nutrient availability to plants, pH 7.5 can cause iron/phosphorus/manganese “nutrient lock-out,” and fish tolerate pH swings poorly (>0.3 pH-unit change within 12–24 hours is flagged as problematic in Ch. 7, Section 7.3.2, p. 108) (Section 3.2.2); water hardness optimum for aquaponics is stated as “about 60–140 mg/litre” for both general hardness (GH) and carbonate hardness/alkalinity (KH) (Section 3.2.5, p. 27), with a separate hardness-classification scale given as soft 0–60, moderately hard 60–120, hard 120–180, very hard >180 mg/L. Salinity is flagged as generally too high above 1 500 μS/cm conductivity or 800 ppm TDS (Section 3.4, p. 29–30).

⚠️MINOR — Two overlapping-but-not-identical “hardness optimum” statements, both from this document, not from different sources: Section 3.2.5’s summary states the optimum for “both hardness types” is “about 60–140 mg/litre” (p. 27), which sits inside, but does not exactly match the boundary of, the separately-given hardness classification scale where “moderately hard” is defined as 60–120 mg/L and “hard” as 120–180 mg/L (same section, p. 28). These are not contradictory data points — one is a recommended target range and the other is a general hardness-naming convention — but a reader skimming only one of the two could reasonably expect them to align exactly at 140 mg/L, which the classification scale does not name as a boundary. Noted for clarity; does not affect any extracted cell since this paper produces no CSV rows.

Fish species profiles and feed conversion (Ch. 7)

This document’s account: Table 7.1 (p. 109) gives vital/optimal temperature, TAN, nitrite, DO, feed-protein percentage and stated grow-out growth rate for seven commercial species: common carp (600 g in 9–11 months), Nile tilapia (600 g in 6–8 months), channel catfish (400 g in 9–10 months), rainbow trout (1 000 g in 14–16 months), flathead mullet (750 g in 9–11 months), giant river prawn (30 g in 4–5 months), and barramundi (400 g in 9–10 months). Tilapia FCR is stated as 1.4–1.8 “in good conditions” (Section 7.2.3, p. 107) — i.e. 1.4–1.8 kg feed per kg of tilapia growth; this is presented as a general industry figure, not a value this document measured. Maximum recommended fish stocking density is 20 kg fish per 1 000 litres of water (10–20 kg/1 000 L “for the small-scale units described in this publication”), reduced to half that (1 kg/100 L) for tanks smaller than 500 litres (Section 8.1.2, p. 125). Catfish (Clariidae) can be stocked much more densely — “up to 150 kg/m³” — because of comprehensive additional mechanical filtration and their air-breathing physiology (Section 7.4.3, p. 113).

Plant nutrient requirements and 12-plant growing guide (Ch. 6, Appendix 1)

This document’s account: Plants need six macronutrients (N, P, K, Ca, Mg, S) and six-plus micronutrients (Fe, Mn, B, Zn, Cu, Mo); the three most commonly deficient in a fish-feed-only nutrient supply are iron, potassium and calcium, because “fish simply do not need the same amounts of iron, potassium and calcium that plants require” (Section 6.2.4, p. 89). Recommended supplementation: chelated iron to reach roughly 2 mg/L in the system generally, or 5 mL of chelated iron per m² of grow bed when deficiency is suspected (Section 6.2.3, p. 89), and 1–2 mg/L for the first three months of a new unit specifically (Section 8.3.1, p. 128). Appendix 1 (p. 169–182) gives pH, spacing, germination temperature/time, growth time, optimal temperature, light exposure, mature plant size and recommended aquaponic method for 12 named vegetables/herbs (basil, cauliflower, lettuce, cucumbers, eggplant, peppers, tomato, beans and peas, head cabbage, broccoli, Swiss chard, parsley), each with a prose growing-conditions/growing-instructions/harvesting section. These are presented as the manual’s consolidated practical guidance drawn from “long-standing aquaponic farming, … horticulture manuals … extension papers, and the professional experience of farmers and researchers” (p. 169), not as data from a controlled trial reported in this document.

Worked design calculations (Ch. 8, Appendix 4, Appendix 7)

This document’s account — feed rate ratio worked example (Section 8.1.1, p. 123–124): to produce 25 heads of lettuce/week (100 heads over a 4-week grow cycle) at 25 heads/m², a system needs 4 m² of growing space; at 50 g feed/m²/day for leafy greens, that requires 200 g feed/day; at fish eating 1–2 percent of body weight/day, that requires 10–20 kg of fish biomass. This is arithmetic built from the manual’s own stated ranges, not a measured outcome.

Ammonia/biofilter sizing worked example (Appendix 4, p. 191–192): of the nitrogen in fish feed, the manual states ~30 percent is retained in fish body mass and ~70 percent is lost — 15 percent as undigested solid waste (of which ~60 percent is removed by clarifiers, leaving ~6 percent to degrade into ammonia in the water) and 55 percent excreted directly as ammonia or ammonia-precursors, for a combined ~61 percent of feed nitrogen becoming ammonia subject to nitrification. Worked example: 200 g of 32-percent-protein feed (nitrogen assumed at 16 percent of protein) yields ~7.5 g ammonia/day, requiring ~13.3 m² of nitrifying-bacteria surface area at a conservative removal rate of 0.57 g ammonia/m²/day, which in turn requires ~44.3 litres of volcanic tuff (SSA 300 m²/m³) — i.e. “1 litre of tuff can convert the ammonia obtained by 4.5 g of feed.” Table A4.1 tabulates this feed-to-media ratio for nine biofilter media types (coarse sand through coarse gravel), spanning specific surface areas from 150 to 5 000 m²/m³.

Cost–benefit worked example (Appendix 7, p. 205–207), explicitly a domestic-scale illustrative model, not a measured farm’s accounts: for a 1 000-litre-fish-tank / 3 m²-growing-space media bed unit growing 50 percent lettuce and 50 percent tomatoes, stated capital cost is USD 700 (Table A7.1), monthly operating cost USD 26.45 (Table A7.2, itemized: seedlings, fingerlings, electricity, water, fish feed, miscellaneous), annual revenue USD 758.40 from an assumed 360 lettuce heads + 54 kg tomatoes + 30 kg fish at stated local (Israeli) market prices accessed 17 September 2013 (Table A7.3), giving an annual net profit of USD 441 and a stated payback period of 19 months (Table A7.4). The manual is explicit that “the figures given in the tables are only intended as guidelines for new users” and that yields, prices and costs “may influence” the outcome considerably (p. 205) — this is presented throughout as a worked illustrative model built on stated assumptions, not as measured accounts from an actual operating unit.

Extraction notes

Type classification — narrative-review, and why not experiment/modelling/policy/technical-note: In every section read (Chapters 1, 2, 3, 6, 7, 8, Appendixes 1, 4 and 7), the document synthesises established RAS/hydroponics engineering knowledge, aquaponics-specific research attributed to named researchers (Rakocy, Lennard, Savidov, Salam), and the authors’ own field/consulting experience into prescriptive ranges and worked illustrative calculations — no original experiment, sample, treatment comparison, or statistical test belonging to this document itself was found. The worked calculations in Ch. 8, Appendix 4 and Appendix 7 (feed-rate-ratio example, ammonia/biofilter sizing, cost–benefit tables) are illustrative arithmetic applying the document’s own stated ranges and assumptions to hypothetical unit sizes — not measurements of a real system, so they cannot support a modelling (computational simulation), experiment, or case-study classification. policy was considered and rejected: the document does discuss where aquaponics is/isn’t appropriate (Box 1, benefits/weaknesses) but frames this evenhandedly as descriptive guidance for practitioners rather than arguing FAO or a reader should pursue a specific course of action. technical-note was considered and rejected on the SCHEMA.md test (“short descriptive report”) — at 262 numbered pages with substantial literature/history synthesis (Section 1.5) this is not short, and it more closely matches narrative-review’s definition (“synthesis with no stated search method”), consistent with the sibling practitioner-manual entry lennardCommercialAquaponicSystems2017 already classified narrative-review in this vault. No systematic search strategy, database list, or inclusion criteria is stated anywhere in the material read, ruling out systematic-review/scoping-review.

⚠️CHECK — Publication year: document’s own citation (2014) vs. zotero-export.csv (2015). The document’s own self-citation on p. iv reads “Somerville, C., Cohen, M., Pantanella, E., Stankus, A. & Lovatelli, A. 2014. Small-scale aquaponic food production…”; the copyright line on the same page reads ”© FAO, 2014”; the PDF’s embedded CreationDate metadata is D:20141124 (24 November 2014); and an independent Crossref search for papers citing this FAO document returned other authors’ reference-list entries dating it “(2014)” as well. Against this, zotero-export.csv lists this item (key YPCE2PY5) with year 2015, sourced from an “Open WorldCat” catalog record (OCLC 898228105) — i.e. a library-cataloging date, which can reflect when a physical/print copy was accessioned rather than the document’s own stated publication date. CLAUDE.md instructs that zotero-export.csv should generally be preferred over the PDF for metadata (it is more reliable against typos and mangled PDF headers), but here the conflict is not a typo — it is the document’s own explicit, internally consistent self-citation and copyright statement (both dated 2014) against a third-party library catalog date reflected in Zotero. Recorded here as 2014 (matching the document’s own citation, copyright notice, and file creation metadata, and the Paper ID somervilleSmallscaleAquaponicFood2014 was generated on this basis), with this discrepancy flagged rather than silently resolved. The PDF filename itself says “2015,” which per CLAUDE.md is not an authoritative source for year regardless.

No DOI found, confirmed by: (1) a full-text search of the PDF for the string “doi” — the only hits are the unrelated word “doing” (twice) and one DOI belonging to a different work cited within Appendix 3, not to this document; (2) a Crossref bibliographic search for the title, which returned only other papers citing this FAO document, not a DOI record for the document itself; (3) FAO’s own Open Knowledge repository and fao.org/fishery/publications listing pages, neither of which displays a DOI (the repository page could not be directly fetched during this extraction — it returned HTTP 403 to automated access — so this is based on the search-result snippets and the FAO publications listing page, not a direct read of the repository’s metadata fields).

No CSV rows. out/somervilleSmallscaleAquaponicFood2014.trials.csv and .plant.csv are header-only (87 and 11 columns respectively, verified by Python csv module field count against the vault’s existing header rows). This document is checked and confirmed to contain no original experimental data of its own anywhere in the material read: Appendix 7’s cost–benefit tables and Chapter 8/Appendix 4’s design calculations are explicitly stated by the authors to be illustrative worked examples built from assumed inputs and general industry ranges (“the figures given in the tables are only intended as guidelines,” p. 205), not measurements of an actual system that was built, stocked, and monitored for this publication. Per SCHEMA.md, only experiment, quasi-experiment, field-trial, and exploratory paper types receive trials.csv/plant_measurements.csv rows; narrative-review is explicitly excluded (“Never create trial rows from a meta-analysis or review”).

Citations already resolved in this vault: James Rakocy’s UVI-model research, named as foundational in Section 1.5 (p. 7), already has a dedicated entry — notes/rakocyAquaponicsIntegrationFish1994.md. Wilson Lennard, named in the same section for “key calculations and production plans” in Australia, already has a dedicated entry for his 2017 book — notes/lennardCommercialAquaponicSystems2017.md — though the specific 1990s–2000s calculation papers referenced in that note’s own “Citations to chase” list (Lennard & Leonard 2004/2006, Lennard 2005 PhD thesis) remain unadded; this document’s brief mention does not identify a separate specific Lennard paper beyond what is already flagged there.

[not reported] fields, grouped: Zotero “Date added” (library timestamp); specific funding body or grant number (institutional FAO output, no external grant stated in the material read).

[unclear] / partially verified fields: The FAO Open Knowledge repository URL’s own metadata (DOI field, if any) could not be directly confirmed because the page returned HTTP 403 to automated fetching during this extraction; the URL is recorded as the best available locator but its content was not independently read.

PDF quality: Clean, fully extractable text layer throughout the pages read; no OCR artifacts or garbled tables encountered. Some inline chemical-formula subscripts (e.g. NH₃, NO₂⁻, NO₃⁻, H⁺) render with digits/superscripts detached from their base characters in raw text extraction (a PDF-extraction layout artifact, not a content error) — verified against the surrounding prose context in every case where this occurred in the material read.

Sampling caveat, stated plainly per CLAUDE.md’s guidance for long-book PDFs: No claim is made that every page, table, or numeric figure in this 262-page manual has been checked. Contradiction-checking (the ⚠️ tiers) was performed only within the ~120 pages actually read in depth (Chapters 1, 2, 3, 6, 7, 8, and Appendixes 1, 4, 7); Chapters 4, 5, 9, the Glossary, and Appendixes 2, 3, 5 (partial), 6 and 8 were sampled only via their Contents-page section headings and were not read in body-text detail, so any contradictions confined to those unread sections would not have been caught here.

Linked claims

Citations to chase

  • todo James Rakocy (University of the Virgin Islands) — UVI-model feeding-rate-ratio and system-design research, named as foundational in Section 1.5 (p. 7) — already in this vault as rakocyAquaponicsIntegrationFish1994; not re-added, but worth checking whether that entry covers the specific UVI feeding-rate-ratio figures this manual draws on.
  • todo Nick Savidov (Alberta, Canada) — cited (Section 1.5, p. 7–8) for an unnamed two-year study finding “significantly superior production of tomatoes and cucumbers when some key nutrients levels were met” in aquaponics; not yet in this vault as a standalone item, and no full citation is given in the pages read to identify the specific paper.
  • todo Mohammad Abdus Salam (Bangladesh Agricultural University) — cited (Section 1.5, p. 8) for furthering home-scale subsistence aquaponics research; not yet in this vault, no full citation given in the pages read.
  • todo Agrios, G.N. (2004) — source for Table 6.2’s nutrient/fungal-disease-prevention effects (p. 100); a plant-pathology textbook reference, not an aquaponics-specific paper, but the only individually-attributed external citation encountered in the material read.
  • todo North Carolina State University’s early aquaponics water-use demonstration (Section 1.5, p. 7) — cited for the claim that integrated systems used “just 5 percent” of the water needed for pond culture of tilapia; no specific paper or researcher name given in the pages read.

Missing/underspecified fields worth flagging

  • [not reported]: Zotero “Date added”; external funding body/grant number.
  • [unclear]: Whether the FAO Open Knowledge repository record (URL above) lists its own DOI — the page could not be fetched directly during this extraction (HTTP 403).

Source: Somerville and Food and Agriculture Organization of the United Nations - 2015 - Small-scale aquaponic food production integrated .pdf

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