Eel research · provenance
Every data source we reviewed
An exhaustive, honest catalogue of the data behind this program — what we ingested and analyzed, what is in use as an ocean or climate input, what is request-gated and still pending, and what we reviewed and deliberately set aside. Licences and status are shown throughout. Where a source was excluded, the reason is stated. Nothing here is cherry-picked: the nulls, the embargoes, and the dead-ends are listed alongside the results.
Status key — INGESTED: pulled and analyzed here · IN USE: a standing input to the models · REQUESTED: access-gated, request sent or drafted · EXCLUDED: reviewed and set aside (reason given) · ANALOG: comparative / cross-species.
Adult telemetry & survey (eel life-stage)
| Source | Provider / licence | How used / why not | Status |
|---|---|---|---|
| EELIAD silver-eel satellite/archival tags | Cefas Data Portal holding 20655 (Righton et al. 2016) Open Government Licence v3 | Oceanic ground truth. Real release→terminal headings cluster on the Sargasso bearing (resultant R=0.76, p≈0, robust to centroid and reconstruction subset); over-ground speed 0.28 m/s independently matches the acoustic anchor; swim-vs-current shows eels compensate for currents; predation is 50% of tag fates; energetics feasible for most eels. | INGESTED |
| ETN / Verhelst acoustic telemetry | VLIZ / Ghent University (EurOBIS) CC0 | 136 female silver eels, 81,302 detections. The departure-speed anchor (~0.28 m/s) that the EELIAD tags independently reproduce. | IN USE |
| England WFD transitional-water eel survey | Cefas Data Portal holding 20473 Open Government Licence v3 | 10,681 surveys, 505 sites, 1981–2018. Occupancy decline is real but gear-dependent and concentrated in the South East; a worked example of how raw single series overstate cleanliness. | INGESTED |
| Burrishoole / Newport 50-year eel trap | Marine Institute Ireland ERDDAP CC-BY | 50 years of daily silver-eel counts. No robust shift in run timing (a quick OLS "earlier migration" did not survive robust estimators) — an honest null. | INGESTED |
| EDA / SUDOANG eel density database | Zenodo 6397009 + Briand et al. 2022 report Open | 48,699 electrofishing operations + 20,101 silver eels (FR/SP/PT). Dams cut upstream presence hard (OR 0.27/sd; 85%→<5%) but reduce silver-eel escapement only 4–12% — so continental dam habitat loss is unlikely to be a primary driver of the collapse (refutes Kettle et al. 2011). | INGESTED |
| Hanningfield reservoir acoustic telemetry | Cefas Data Portal holding 21846 Open Government Licence v3 | Reservoir behavioural telemetry; low priority for the oceanic question. Resolves an old licensing uncertainty. | INGESTED |
Larvae & spawning ground
| Source | Provider / licence | How used / why not | Status |
|---|---|---|---|
| ICES Eggs & Larvae Database (leptocephali) | ICES (McCleave/Miller compilation), 1862–2007 CC-BY | The open larval record. Back-tracks spawning origin (~26°N, 66–67°W) and validates the thermal anchor; the result reproduces on this open data without the restricted file. | IN USE |
| Als et al. 2011 Sargasso larvae | Dryad 10.5061/dryad.8155 Open | 271 A. anguilla + 117 A. rostrata larvae with coordinates; open spawning-area source points for inversion and panmixia. | IN USE |
| Miller et al. 2015 leptocephalus compilation | M. J. Miller (pers. comm.) Restricted — not redistributed | Corroboration only; no core result depends on it (the open ICES record carries the finding). | IN USE |
Ocean & climate inputs
| Source | Provider / licence | How used / why not | Status |
|---|---|---|---|
| SST — OISST v2.1, ERSST v5, COBE-SST2, OSTIA | NOAA NCEI / JMA / CMEMS Open | The 1854–2025 SST record for the isotherm-vs-front divergence and its attribution; multi-product robustness. | IN USE |
| GLORYS12 reanalysis + HYCOM currents | Copernicus Marine / HYCOM Copernicus / open | Eddy-resolving currents for the larval-transport IBM and the swim-vs-current decomposition; front-insensitivity holds across both products. | IN USE |
| GlobColour chlorophyll + net primary production | Copernicus Marine OCEANCOLOUR_GLO_BGC_L4 Copernicus | Route productivity along the drift corridor. Both biomass (CHL −5.3%/dec) and production (PP −3.3%/dec) decline in the drift season and survive AMO control — a warming-forced candidate mechanism, not excluded. | IN USE |
| Subsurface T — IAP/Cheng, EN4, Argo | ocean.iap.ac.cn / Met Office / argopy Open | Confirms warming reaches the ~150–200 m spawning depth across three products. | IN USE |
| Winds — ERA5, CCMP, NCEP/NCAR | ECMWF (ARCO-ERA5) / RSS / NOAA PSL Open | Ekman/convergence diagnostics; the wind leg was tested and dropped (product-robust null). | IN USE |
| NOAA Global Drifter Program | NOAA AOML ERDDAP Open | Real Lagrangian ground truth: observed passive delivery (~3%) and the measured dispersion that bounds the inversion horizon. | IN USE |
| Sargassum AFAI | NOAA AOML / USF Open | Floating-algae habitat index; nursery-band habitat cross-check. | IN USE |
| CMIP6 ensemble | Pangeo (Google Cloud) Open | Forward isotherm trajectory and the prospective habitat-edge pressure (+1.7/+3.3 °C by 2100). | IN USE |
| Climate indices — AMO, NAO, GISTEMP | NOAA PSL / CPC / NASA GISS Open | Internal-variability controls and the forced/warming attribution (frozen snapshots for reproducibility). | IN USE |
Recruitment & stock
| Source | Provider / licence | How used / why not | Status |
|---|---|---|---|
| ICES WGEEL glass-eel recruitment index | ICES Working Group on Eels Report annexes | The recruitment series whose link to spawning climate does not survive de-trending. | IN USE |
| SUDOANG silver-eel escapement (EDA 2.3) | Briand et al. 2022 (GT4 deliverable) Open report | The dam counterfactual: escapement with vs without dams (4–12% reduction); total SW-Europe stock 374.3 M eels. | IN USE |
Requested / access-gated
| Source | Provider / licence | How used / why not | Status |
|---|---|---|---|
| Reconstructed EELIAD daily tracks | Cefas / D. Righton Embargoed (EIR 12(4)(d)) | The dense reconstructed routes are withheld pending an unfinished synthesis paper (expected Dec 2026). We use the open release/terminal/geolocation subset instead. | REQUESTED |
| Righton et al. 2022 "direct evidence" Sargasso tracks | Corresponding authors (Cefas) On reasonable request | Newer PSAT tracks where some eels reached the spawning area; request drafted to the Cefas data channel. | REQUESTED |
| Béguer-Pon et al. 2015 American-eel PSAT | Authors (DFO / U. Laval) On request | Would enable a same-method orientation comparison across species (European vs American). Request sent. | REQUESTED |
| Australian long-finned eel PSAT (2025) | Authors On request | A third-species comparative (Anguilla reinhardtii → Coral Sea). Request drafted. | REQUESTED |
| Continuous Plankton Recorder | Marine Biological Association Data-use agreement | Plankton 1958–present to extend the corridor-productivity series back before the satellite era (does the decline predate the 1980s collapse?). Request sent. | REQUESTED |
| Japanese-eel larval / catch data | Aoyama / Tsukamoto On request | Comparative spawning-area larvae; noted as not yet compiled by the authors. | REQUESTED |
Reviewed & deliberately excluded
| Source | Provider / licence | How used / why not | Status |
|---|---|---|---|
| European eel reference genome + population genomics | ENA / GenBank (GCA_013347855.1; Jacobsen/Enbody comparative) Open | Open but large and specialized (VCFs + selection scans); a separate pop-gen project. The panmixia / two-species result is already established, so out of scope for this program. | EXCLUDED |
| OTN American-eel acoustic telemetry | Ocean Tracking Network Login-gated | Estuarine/riverine, not the oceanic release→terminal geometry needed for an orientation comparison. | EXCLUDED |
| DBEEL rivers spatial database (PostGIS dumps) | Zenodo 6384022 Open | The GIS substrate (river-network geometry, basin polygons) behind the EDA tables; ~4 GB of database dumps with no new eel observations. Escapement numbers recovered from the published report instead. | EXCLUDED |
| Otolith microchemistry (Sr:Ca life history) | Various (HAL, theses, reports) Mixed / paywalled | Reviewed; mostly extract-from-PDF rather than clean deposits. Held for a future life-history slice. | EXCLUDED |
| Movebank oceanic-turtle / eel tracks | Movebank Login + data-use agreement | No open Anguilla oceanic tracks; used open drifters and Dryad turtle sets instead. | EXCLUDED |
Comparative / analog
| Source | Provider / licence | How used / why not | Status |
|---|---|---|---|
| Anguilla rostrata occurrence | OBIS / GBIF Open | American-eel distribution for the comparative "same gyre, two continents" framing; modeled origins converge near the Sargasso (~1.9° from the European-eel origin). | ANALOG |
| Cross-species reproductive-climate database | Six public databases, GBIF-resolved Open (compiled) | A 14k-species climate-reproduction asset built to test a generalization of the eel pattern — which then failed independent testing (reported openly, nulls included). | ANALOG |
This catalogue is maintained alongside the research notebook. Data redistributed here retain their original licences; restricted and embargoed sources are named but not redistributed. Last reviewed July 2026.