Fresh Fish

Overview

Source-grounded narrative on this page is populated incrementally from the routed source pages; the evidence-summary table is regenerated by the source-routing layer as sources accumulate.

Who this page is for

This page serves brand legal teams, retailer-compliance reviewers, HMTc certification staff, and regulators reviewing fresh-and-frozen-finfish category certification. The product category covers fresh and frozen finfish whole, fillets, steaks, ground/portioned products, and minimally processed (raw, smoked, cured, marinated) preparations. It does NOT cover canned fish (see Canned Fish — REDIRECT (Cat 6 → canned-seafood)), seafood-containing infant foods (see Fish-Containing Baby Foods), shellfish, bivalves, or cephalopods (those route to ingredients-level pages and the broader Seafood category).

Fresh fish has different contamination dynamics from canned fish in three respects. First, the dominant analyte remains mercury (MeHg/tHg), but the secondary metals (Pb, Cd, tAs) are frequently below the analytical limit of quantification in finfish muscle, particularly in inland freshwater species — Rusko 2026’s 460-fish Latvian inland-lake survey reported Pb, Cd, and tAs all below LOQ across all 7 species. Second, no packaging migration concerns exist for fresh/frozen format (no Sn or Al migration). Third, trophic-level stratification is a stronger predictor of MeHg burden than species identity per se — apex carnivores accumulate MeHg via biomagnification, while detritivores and herbivores stay low. This makes species-and-trophic-level documentation the primary certification-relevant axis for fresh fish; the canned-fish concerns about can-material migration do not apply.

Fresh fish includes a distinct sub-category that needs separate certification consideration: recreational and self-caught fish from sport-fish populations (per Cleary 2021’s documentation of state-level US advisory frameworks). 45 of 46 US states publish MeHg-specific advisories targeting freshwater sport fish; commercial fresh-fish certification standards should reference but not duplicate these state-level frameworks.

Methodology

This page will report literature evidence’s product-category-page template. Speciation is non-substitutable (iAs vs tAs, Cr-VI vs total Cr, MeHg vs tHg); basis is preserved and labeled; non-detect handling follows the source’s own convention; pooling avoided across LOQ, period, geography, and analytical-basis differences. HMT&C certification thresholds are developed under the certification program at heavymetaltested.com, not on this page; this public page reports literature evidence only.

Literature Evidence Summary

Pending: regenerated by tools/evidence/apply-product-hmtc-evidence-summaries.mjs once sources route and the pooling engine emits aggregate rows for this product category.

Source Evidence Inventory

63+ source pages route to this category. Most load-bearing per-metal evidence:

Methylmercury (MeHg) and total mercury (tHg) — dominant concern across all fresh-fish sub-categories:

• Risk-Benefit Assessment of Mercury, Lead, Cadmium, and Arsenic in Inland Fish from Latvian Lakes — 460 inland freshwater fish across 7 species and 5 Latvian lakes. tHg/MeHg measurable across the sample set with some samples exceeding the EU 0.5 mg/kg cap; MeHg is the dominant Hg form as expected. Pb, Cd, and tAs ALL below LOQ across the entire 460-sample set — a load-bearing finding that inland-lake freshwater fish in northern Europe carry essentially no Pb/Cd/As burden, making MeHg the sole metal-of-concern for this regional sub-category. Risk-benefit analysis: MeHg risk may outweigh nutritional benefit for at-risk populations (pregnant women, children) at high-consumption scenarios for predatory freshwater species (notably pike).
• Presence of Nematodes, Mercury Concentrations, and Liver Pathology in Carnivorous Freshwater Fish from La Mojana, Sucre, Colombia: Assessing Fish Health and Potential Human Health Risks — 326 fish from La Mojana wetland, Colombia. Mean tHg 0.31 µg/g wet weight overall. Peak species-season concentrations: Sternopygus macrurus 0.46 µg/g (rainy season), Cynopotamus magdalenae 0.54 µg/g (dry season). Apex carnivores (Hoplias malabaricus, trophic level 4.5) at top of distribution. CRM-validated DMA-80; MeHg fraction assumed at 90% per USEPA 1999.
• Assessment of total mercury content in fish muscle tissue from the middle basin of the Pastaza River, Ecuador — 40 fish from middle-basin Pastaza River, Ecuador (Amazonian). Trophic-level-stratified findings: carnivores (Charax 0.241, Cetopsis plumbea 0.116, Hoplias malabaricus 0.020-0.160 µg/g) vs herbivores (Hypostomus lowest values). Daily safe consumption range 6-199 g/day for children, 29-928 g/day for adults — over an order of magnitude depending on species. This source is the canonical evidence that trophic level, not species per se, drives MeHg burden.
• Correction: Mercury Concentrations in Sport Fish from Colorado Reservoirs — Walleye, northern pike, smallmouth bass from Colorado reservoirs. Specific corrected values in the source document; literature range for these species in temperate-freshwater reservoirs is typically 0.1 to >1.0 mg/kg, with walleye and pike toward the high end via biomagnification.
• Systematic review and spatiotemporal assessment of mercury concentration in fish from the Tapajós River Basin: implications for environmental and human health — Mercury Tapajós basin systematic review covering 36 studies (1992-2022), Pan-Amazon georeferenced. Tropical-river biomagnification dynamics in Amazonian fisheries.
• Mercury in aquatic ecosystems of two indigenous communities in the Piedmont Ecuadorian Amazon: evidence from fish, water, and sediments — Ecuadorian Amazon fresh fish Hg; supplements Pastaza data.
• Stable isotopes unveil ocean transport of legacy mercury into Arctic food webs — Greenland arctic fish Hg with isotope-based source attribution.
• Health risk assessment of methyl mercury from fish consumption in a sample of adult Qatari residents — Qatar coastal marine fish; provides marine counterpart to inland-lake data.
• Mercury levels in fish in the Valencian Community: temporal evolution (2011-2017) and associated factors — Spanish Mediterranean fresh-fish Hg market survey.
• Seasonal characterization of mercury contamination along the Portuguese coast: human health and environmental risk assessment — Portuguese coastal seasonal sampling.
• A preliminary assessment of mercury, methylmercury and other potentially toxic elements in largemouth bass (Micropterus salmoides) from the Almadén mining district — Spanish bass (Almadén legacy-mining region) Hg in fish.
• Methylmercury in fish and seafood – health risk assessment of new data from the BfR MEAL study — German BfR MEAL study including fresh-fish matrices.

Pb, Cd, tAs in fresh fish (often below LOQ; report what’s there):

• Risk-Benefit Assessment of Mercury, Lead, Cadmium, and Arsenic in Inland Fish from Latvian Lakes (above) — all three metals below LOQ across 460 inland-lake samples. Load-bearing finding for inland-lake low-Pb-Cd-As status.
• Heavy Metals Assessment and Health Risk to Consumers of Two Commercial Fish Species from Polyculture Fishponds in El-Sharkia and Kafr El-Sheikh, Egypt: Physiological and Biochemical Study — Egyptian aquaculture multi-metal fresh-fish characterization.
• Trace and heavy metal concentrations in pectoral fin of Acipenser stellatus (stellate sturgeon) from the Caspian Sea — Caspian Sea sturgeon multi-metal.
• More Danger Than Meets the Eye: Potentially Toxic Element Contamination in Fish from the Western Pará Poses Significant Hazards to Local Communities — Western Pará (Brazilian Amazon) fish multi-metal.
• Heavy metals in Garra shamal freshwater fish from Oman: accumulation and health risk — Garra (cyprinid) freshwater fish Oman multi-metal.

Arsenic speciation framework (mostly organic in marine fish):

• The Need to Unravel Arsenolipid Transformations in Humans — Comprehensive As speciation in seafood; iAs typically ~10% of tAs in fish. Important for fresh-fish certification standards that need to distinguish iAs (toxicologically relevant) from total As (which includes nontoxic arsenobetaine in marine species). Freshwater fish have less data on As speciation than marine species; assume similar ~10% iAs fraction in absence of speciated data.

Regulatory and advisory framework:

• Commission Regulation (EU) 2022/617 of 12 April 2022 amending Regulation (EC) No 1881/2006 as regards maximum levels of mercury in fish and salt — EU 2022/617 per-species Hg cap (the operative current EU regulation for fishery products including fresh fish).
• Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006 — Full EU contaminants framework.
• Commission Regulation (EC) No 1881/2006 setting maximum levels for certain contaminants in foodstuffs and Commission Regulation (EC) No 466/2001 setting maximum levels for certain contaminants in foodstuffs — Pre-2023 and pre-2007 EU frameworks cited by older sources in the category.
• Comparison of Recreational Fish Consumption Advisories Across the USA — US state-by-state advisory comparison; 45/46 states have MeHg advisories targeting freshwater sport fish. The canonical reference for the US-state-advisory landscape for fresh/sport fish.
• Mercury Update: Impact on Fish Advisories — US EPA framework anchor.
• Organotin Compounds in Aquatic Products Available at Local Markets — Hong Kong organotin (TBT/DBT) in aquatic foods; supplemental for organotin contamination in coastal/aquaculture fish.

Broad Product Context: Author-Scope Index

Pending: regenerated by tools/evidence/apply-product-broad-context.mjs once broad-scope sources route to this page.

Federal/Regulatory Limits vs Field Findings

Pending: regenerated by tools/apply-product-crosswalk-sections.mjs once applicable_regulations are identified and field-finding evidence is pooled.

Levers to reduce contamination

Fresh fish shares the species-selection-is-dominant pattern with seafood and canned fish, but with sharper trophic-level differentiation and no packaging-migration concerns. Ordered by impact magnitude:

Sourcing levers (highest impact; trophic level is the strongest single predictor):

• Trophic level — the dominant lever for fresh fish. Per Paz-Suconota 2024 Ecuadorian Amazon and Fuenteslopez 2025 Colombian wetland data, trophic level is a stronger predictor of muscle MeHg than species identity per se. Apex carnivores (Hoplias malabaricus, walleye, northern pike, swordfish, shark, large tuna) accumulate MeHg through biomagnification at orders-of-magnitude higher than herbivores (Hypostomus) and detritivores. For certification standards, requiring documentation of trophic level rather than just species name allows more defensible MeHg-driven categorization. Within the same species across water bodies, trophic-position context (food web composition, predator-prey relationships) can produce 5-10× variability.
• Species selection within trophic levels. Salmon (anadromous, mid-trophic) carries less MeHg than open-ocean large pelagics. US-farmed catfish, US/EU-farmed trout, and farmed tilapia have systematically lower MeHg than wild-caught predatory species. Per Cleary 2021 state advisory data, the species-selection lever in the US is anchored on the FDA “Best Choices” list (salmon, anchovies, mackerel-Atlantic, herring, sardines, oysters, etc.) vs the “Choices to Avoid” list (king mackerel, marlin, orange roughy, shark, swordfish, tilefish-Gulf of Mexico, bigeye tuna).
• Origin region specification — water-body and regional MeHg differentiation. Inland lakes vary widely in MeHg from negligible to advisory-triggering levels driven by atmospheric Hg deposition, sediment Hg burden, and water chemistry (acidic peatland waters mobilize Hg more readily). Per Rusko 2026 (Latvian inland lakes), regional certification standards may legitimately differ. Marine origin matters too: Mediterranean swordfish vs Atlantic swordfish, Gulf of Mexico tilefish vs Atlantic tilefish (the FDA-advisory distinction). Sourcing certification should specify the catch region, not just the species.
• Aquaculture vs wild-caught. Farmed salmon, trout, tilapia, and catfish have substantially lower MeHg than wild-caught counterparts because the feed regime is controlled (feed-derived MeHg is the bottleneck). Wild-caught equivalents accumulate over a lifetime in open water. For HMTc certification distinguishing farmed vs wild within a species, the farmed sub-category will typically pass tighter MeHg ceilings.
• Self-caught/sport-fish exclusion or separate framework. Per Cleary 2021, self-caught freshwater fish carries inherent variability that commercial certification cannot anchor against. Commercial fresh-fish certification standards should not extend to recreational catch; that remains the state-level advisory framework’s territory.

Testing and QC levers:

• Lot-level tHg testing on predatory or high-trophic-level fresh fish. Same variability concern as canned tuna: individual-fish MeHg varies by 5-10× even within a single species in one water body. Sport-fish or commercial-predator certification should not rely on species-average — lot-level testing is the defensible minimum.
• Speciated MeHg vs tHg-as-proxy. Fuenteslopez 2025 and Paz-Suconota 2024 used the USEPA-convention assumption that MeHg = 90% (Fuenteslopez) or 80% (Paz-Suconota) of tHg in freshwater fish muscle. For certification work, this convention may be acceptable for low-stakes uses, but any HMTc standard explicitly framed in MeHg should require direct speciation by GC-ICP-MS or LC-ICP-MS at a lot-sample basis.
• Multi-metal screening on regions with documented Pb/Cd/As burden. Rusko 2026’s all-below-LOQ Pb/Cd/tAs Latvian finding does NOT generalize to all fresh-fish sources. Egyptian aquaculture (Abbas 2023), Caspian sturgeon (Bakhshalizadeh 2024), and Brazilian Amazon (Albuquerque 2026) have documented non-Hg metal burdens warranting routine screening. Region-specific QC requirements rather than uniform-global certification panels.

Processing levers (limited impact in fresh format):

• Skinning and trimming. Removes some Pb and Cd from subcutaneous tissue and skin; effect is modest in fresh fillets and primarily relevant for whole-fish preparations where skin would be consumed.
• Cooking (frying, grilling, steaming, etc.). Does NOT reduce MeHg — binds to muscle protein and survives all cooking methods. Some Pb and Cd may leach into broths during boiling/steaming, but the leached fraction is small and recovered if the broth is consumed.
• Cold-storage and freeze-thaw cycles. No effect on heavy-metal content. Material remains in muscle protein regardless of storage temperature or duration.

Formulation levers (point of consumption / portion-control):

• Portion-size and consumption-frequency standards in advisory. Where certification cannot guarantee a species-level MeHg ceiling, consumption-frequency guidance (e.g., “no more than 2 servings per week of this species”) shifts risk per-meal vs cumulative-weekly. Documented in Paz-Suconota 2024’s daily safe consumption range (6-199 g/day children) and Cleary 2021’s meal-size guidance (median 0.227 kg/meal across states).
• Substitution within product lines. Same logic as canned-fish: replacing tuna fillets with salmon fillets in a meal-kit or grocery line shifts the MeHg burden by 5-10× without changing the consumer-facing product category.

Regulatory and certification levers:

• EU 2022/617 per-species Hg caps — 0.5 mg/kg general default, 1.0 mg/kg for listed predatory species. Operative current EU framework.
• FDA fish-consumption advisory framework — the species-categorized “Best/Good/Avoid” tiers are the consumer-protection backdrop for any US commercial fresh-fish certification.
• EFSA MeHg PTWI vs EPA RfD framing gap — same as in Seafood and Canned Fish — REDIRECT (Cat 6 → canned-seafood). Anchoring HMTc certification on the stricter EPA framing offers stronger consumer-protection defensibility.
• State-level advisory deference. Recreational/sport-fish certification should reference but not duplicate state-level frameworks per Cleary 2021’s documentation of substantial cross-state variation.

How standards math uses this page

This page reports what the peer-reviewed and government literature says about heavy-metal concentrations in this product category; it publishes no certification thresholds of its own. Certification criteria are set separately under the Heavy Metal Tested & Certified program at heavymetaltested.com, which reads this page as its literature baseline. The two are kept apart by design, so this page remains an independent record of the evidence rather than a justification for any threshold.

Historical recalls and enforcement

Public-record regulatory events material to fresh fish, framed as events not brand rankings (per Part 12):

• EU Commission Regulation (EU) 2022/617 (operative current EU framework for fishery products including fresh fish; per-species Hg cap 0.5 mg/kg default, up to 1.0 mg/kg for listed predatory species). See eu-reg-2022-617-mercury-fishery.
• EC 1881/2006 framework (superseded May 2023; cited by most pre-2023 sources in this category). See Commission Regulation (EC) No 1881/2006 setting maximum levels for certain contaminants in foodstuffs.
• EC 466/2001 (the EC 1881/2006 predecessor, in force 2001-2007; older sources may cite it). See Commission Regulation (EC) No 466/2001 setting maximum levels for certain contaminants in foodstuffs.
• US FDA-EPA joint “Eating Fish: What Pregnant Women & Parents Should Know” framework (ongoing, last major update 2017+) — species-categorized “Best Choices / Good Choices / Choices to Avoid” tiers driving commercial fresh-fish certification context.
• State-level US fish consumption advisories — 45 of 46 states publish MeHg-specific advisories per Cleary 2021. State frameworks generally extend the federal framework to recreationally-caught freshwater fish and add water-body-specific or species-specific guidance. RfD basis ranges 7×10⁻⁵ to 5.6×10⁻⁴ mg/kg-day across the 39 states citing a numeric value (median 1×10⁻⁴ mg/kg-day, the EPA value).
• NOAA/USDA fish-and-seafood traceability frameworks (Seafood Import Monitoring Program — SIMP, US Lacey Act, EU IUU regulation) require origin and species documentation at point of import. These traceability frameworks indirectly support HMTc certification because species-and-origin documentation is the foundation for any MeHg-driven sub-categorization standard.
• Periodic FDA fresh-fish recalls for elevated Hg, scombroid toxin, or Listeria appear in the FDA recall database; Hg-driven recalls are typically tied to FDA action-level exceedances on individual lots of large predatory species. Pattern over time is policy-trajectory context for HMTc certification.

For HMTc-facing material citing regulatory backdrops, reference the regulation page directly rather than naming specific brand recall events. Brand-by-brand recall enumeration belongs in the private brand-intelligence build per Part 26, not on this public page.

References

Works cited in this page’s text, in first-appearance order. This is not the full corpus for this page; it is only what the prose above draws on. The complete set of sources is listed under Sources below. Each title links to its source record, which carries the ingest receipt, the extracted values, and the file hash of the document it was built from.

1. Risk-Benefit Assessment of Mercury, Lead, Cadmium, and Arsenic in Inland Fish from Latvian LakesRusko L, Ozola-Davidane R, Kviesis J, and Klavins M · Foods · 2026 · doi.org/10.3390/foods15091516Review
2. Presence of Nematodes, Mercury Concentrations, and Liver Pathology in Carnivorous Freshwater Fish from La Mojana, Sucre, Colombia: Assessing Fish Health and Potential Human Health RisksFuentes-Lopez Katerin, Olivero-Verbel Jesus, and Caballero-Gallardo Karina · Archives of Environmental Contamination and Toxicology · 2025 · doi.org/10.1007/s00244-025-01117-wReview
3. Assessment of total mercury content in fish muscle tissue from the middle basin of the Pastaza River, EcuadorPaz-Suconota F, Fernández L, Carpintero-Salvador N, Ruiz-Urigüen M, Brück SA, Galarza FER, et al. · PLOS ONE · 2024 · doi.org/10.1371/journal.pone.0310688Review
4. Correction: Mercury Concentrations in Sport Fish from Colorado ReservoirsLepak JM, Bhavsar SP, and Eagles-Smith CA · PLOS ONE · 2025 · doi.org/10.1371/journal.pone.0319526Review
5. Systematic review and spatiotemporal assessment of mercury concentration in fish from the Tapajós River Basin: implications for environmental and human healthAuzier Guimarães KL, do Nascimento Andrade SJ, Liscano-Carreño AA, de Oliveira RB, and Ribeiro Rodrigues LR · ACS Environmental Au · 2025 · doi.org/10.1021/acsenvironau.4c00053Review
6. Mercury in aquatic ecosystems of two indigenous communities in the Piedmont Ecuadorian Amazon: evidence from fish, water, and sedimentsEscobar-Camacho D, Escobar-Camacho B, Rodas-Trejo J, Tafur-Ramos J, Escobar-Ortiz A, Miserendino G, et al. · Environmental Science and Pollution Research · 2024 · doi.org/10.1007/s10646-024-02764-wReview
7. Stable isotopes unveil ocean transport of legacy mercury into Arctic food websDietz R, Søndergaard J, Rigét FF, Bach L, Basu N, Fort J, et al. · Nature Communications · 2025 · doi.org/10.1038/s41467-025-60356-6Review
8. Health risk assessment of methyl mercury from fish consumption in a sample of adult Qatari residentsAl-Sulaiti MM, Al-Ghouti MA, Ramadan GA, and Soubra L · Environmental Science and Pollution Research · 2023 · doi.org/10.1007/s10661-023-11194-wReview
9. Mercury levels in fish in the Valencian Community: temporal evolution (2011-2017) and associated factorsBlanco C, Ballester F, Báguena R, Marín S, LLop S, López-González U, et al. · Revista Española de Salud Pública · 2023 · www.sanidad.gob.esReview
10. Seasonal characterization of mercury contamination along the Portuguese coast: human health and environmental risk assessmentCardoso PG, Morais H, Crespo D, Tavares D, Pereira E, and Pardal MA · Environmental Science and Pollution Research · 2023 · doi.org/10.1007/s11356-023-29495-5Review
11. A preliminary assessment of mercury, methylmercury and other potentially toxic elements in largemouth bass (Micropterus salmoides) from the Almadén mining districtBarquero JI, Hidalgo JJ, Esbrí JM, Higueras P, and García-Ordiales E · Environmental Geochemistry and Health · 2024 · doi.org/10.1007/s10653-024-02326-3Review
12. Methylmercury in fish and seafood – health risk assessment of new data from the BfR MEAL studyGerman Federal Institute for Risk Assessment (BfR) · BfR Opinion 023/2024 · 2024 · doi.org/10.17590/20240626-094256-0Government
13. Heavy Metals Assessment and Health Risk to Consumers of Two Commercial Fish Species from Polyculture Fishponds in El-Sharkia and Kafr El-Sheikh, Egypt: Physiological and Biochemical StudyAbbas MMM, EL-Sharkawy SM, Mohamed HR, Elaraby BE, Shaban WM, Metwally MG, et al. · Biological Trace Element Research · 2023 · doi.org/10.1007/s12011-023-04007-1Review
14. Trace and heavy metal concentrations in pectoral fin of Acipenser stellatus (stellate sturgeon) from the Caspian SeaBakhshalizadeh S, Bani A, Abdolmalaki S, and Hedayati A · Environmental Science and Pollution Research · 2024 · doi.org/10.1007/s11356-024-32653-yReview
15. More Danger Than Meets the Eye: Potentially Toxic Element Contamination in Fish from the Western Pará Poses Significant Hazards to Local CommunitiesAlbuquerque FEA, Monteiro GC, Freitas MB, Silva EO, Aviz RL, and Lima MO · ACS Omega · 2026 · doi.org/10.1021/acsomega.5c10676Review
16. Heavy metals in Garra shamal freshwater fish from Oman: accumulation and health riskAl Jufaili S, Al Khamisi S, Al Busaidi M, and Al Habsi S · Environmental Science and Pollution Research · 2024 · doi.org/10.1007/s11356-024-32229-wReview
17. The Need to Unravel Arsenolipid Transformations in HumansChávez-Capilla T · DNA and Cell Biology · 2022 · doi.org/10.1089/dna.2021.0476Review
18. Commission Regulation (EU) 2022/617 of 12 April 2022 amending Regulation (EC) No 1881/2006 as regards maximum levels of mercury in fish and saltEuropean Commission · Official Journal of the European Union, OJ L 115, 13.4.2022, pp. 60–63 · 2022 · eur-lex.europa.euRegulation
19. Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006European Commission · Official Journal of the European Union · 2023 · eur-lex.europa.euRegulation
20. Comparison of Recreational Fish Consumption Advisories Across the USACleary BM, Romano ME, Chen CY, Heiger-Bernays W, and Crawford KA · Current Environmental Health Reports · 2021Review
21. Mercury Update: Impact on Fish AdvisoriesUS EPA Office of Water · US EPA Fact Sheet EPA-823-F-99-016 · 1999 · www.epa.govGovernment
22. Organotin Compounds in Aquatic Products Available at Local MarketsCentre for Food Safety, Food and Environmental Hygiene Department, and Government of the Hong Kong Special Administrative Region · Risk Assessment Studies Report No. 60, Centre for Food Safety, Hong Kong FEHD · 2019 · www.cfs.gov.hkGovernment

Sources

Auto-generated from source-page frontmatter, with the “Used on this page for” column populated by per-page synthesis.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.