European Eel

A 5,000 km Migrator Driven to Critical Endangerment by an Illegal Glass-Eel Trade

The European eel is a catadromous fish: it hatches in the Sargasso Sea (subtropical North Atlantic), drifts as larvae for ~12–18 months on the Gulf Stream toward European and North African coasts, transforms into transparent "glass eels" at the continental shelf, ascends rivers across Europe and North Africa, lives 5–25+ years in freshwater as a "yellow eel," then matures into a "silver eel" and migrates back to the Sargasso to spawn once and die [ICES 2024; Tesch 2003]. The species' recruitment — the annual return of glass eels to European coasts — fell to approximately 1–5% of the 1960s–80s baseline between 2010 and 2020 and has not recovered [ICES 2024]. The IUCN lists Anguilla anguilla as Critically Endangered [Pike et al. 2020]. The proximate cause of recent decline is no longer ambiguous: it is the illegal trafficking of glass eels to East Asian aquaculture markets, on a scale comparable in monetary value to international illegal drug trades.

Biology and identification

Anguilla anguilla adults reach 60–150 cm and 4–6 kg (females are larger). Body is serpentine, with continuous dorsal-anal-caudal fin, small pectoral fins, no pelvic fins, and a slimy mucus coating. Color varies by life stage: glass eels are transparent (~7 cm); yellow eels are olive-brown above with yellow flanks (juvenile to subadult); silver eels turn metallic dark-back, white-belly during the maturation phase that precedes the spawning migration [Tesch 2003].

The species' reproductive biology is the binding constraint on conservation. Eels spawn only once in their lifetime, after a 5,000 km migration to the Sargasso Sea. No European eel has ever been observed spawning in the wild. Captive breeding has been attempted at multiple research facilities over decades; producing larvae from captive broodstock is difficult, and rearing those larvae through metamorphosis to the glass-eel stage has been achieved only at small scale and never at population-relevant volumes [Tomkiewicz et al. 2019]. There is no aquaculture-based eel population; all "farmed" eels in commerce begin life as wild-caught glass eels.

Habitat and range

The European eel's range is one of the largest of any fish: the entire Mediterranean Sea and North Atlantic continental shelf from Mauritania to Iceland, plus inland freshwaters across all of Europe, North Africa, and parts of the Middle East. Adult eels are remarkably tolerant of habitat conditions — they survive in rivers, lakes, brackish lagoons, drainage ditches, and farm ponds [Tesch 2003]. Spawning is restricted to a region of the Sargasso Sea south of Bermuda, identified primarily through historical larval-catch distributions [Schmidt 1923].

Conservation status

The European eel is listed as Critically Endangered on the IUCN Red List [Pike et al. 2020]. The species was placed on CITES Appendix II in 2009 — meaning international commercial trade requires permits proving it is non-detrimental to species survival. Since December 2010, the European Union has suspended all trade in A. anguilla (and its products) between EU member states and non-EU countries, effectively banning exports of glass eels to Asia [European Commission 2010]. The International Council for the Exploration of the Sea (ICES) advises annually on European eel; the long-standing advice is that "all anthropogenic mortality should be reduced to or kept as close to zero as possible" [ICES 2024].

Threats

Illegal glass-eel trafficking is the principal documented driver of recent decline. Glass eels are wild-harvested on European coastlines during the late-winter and spring migration runs, smuggled out of the EU by air freight (typically packaged as "live fish" or mislabeled), and sold to aquaculture operations in mainland China and other East Asian countries that rear them to market size for the Japanese kabayaki (grilled eel) market. Europol coordinated investigations have identified the European eel trafficking trade as one of the highest-value wildlife crimes in Europe, with single shipments valued in the millions of euros [Europol/EU SOCTA 2021; Stein et al. 2016].

A 2019 investigation by Europol and EU member-state customs estimated that approximately 350 million glass eels were trafficked annually from Europe to Asia at the peak — likely a substantial fraction of the entire annual European glass-eel recruitment [Europol/Eurojust 2019; Pew Charitable Trusts 2020].

Other contributors include habitat loss (river damming, fragmentation of migration routes, channelization, drainage), pollution, the swimbladder parasite Anguillicoloides crassus (an invasive nematode introduced from Asia in the 1980s that compromises silver-eel swim function and may impair their ability to complete the spawning migration), and ocean-current shifts associated with climate change affecting larval transport [ICES 2024].

What is being done

• CITES Appendix II + EU export suspension — the principal legal framework. Each shipment of glass eels (or eel products) crossing an EU external border requires CITES permitting; the EU's blanket trade suspension makes any commercial export effectively illegal [European Commission 2010].
• Europol "Operation Lake" — coordinated annual enforcement operations focused on the European glass-eel trafficking trade. Operation Lake VIII in 2023 reported the interception of millions of glass eels and tens of arrests across multiple member states [Europol 2023; verification pending on exact figures by year].
• Sustainable Eel Group — a multi-stakeholder organization developing the Sustainable Eel Standard, which certifies eel sourcing meeting biological and traceability criteria [Sustainable Eel Group 2024].
• National eel management plans — every EU member state with a recreational or commercial eel fishery is required under EU Council Regulation 1100/2007 to operate an Eel Management Plan with objectives of restoring 40% of escapement of silver eels to the marine spawning migration [European Council 2007]. Implementation has been uneven.

How readers can help

• Do not eat eel. This is the highest-leverage individual action. Almost all eel on European, North American, and Japanese restaurant menus — including kabayaki / unagi at Japanese restaurants — has wild origins through the trafficking-funded supply chain. The Sustainable Eel Group's certification covers a very small fraction of global eel trade; certified eel is rare in restaurants and difficult to verify in retail [Sustainable Eel Group 2024]. The straightforward rule: do not order eel.
• Support European wildlife-crime enforcement. Europol's Operation Lake and the national customs and police agencies coordinating it receive support from multiple NGOs and donor partners. Wildlife Justice Commission, TRAFFIC, and IUCN all run targeted programs supporting eel-trafficking enforcement.
• Support river-restoration NGOs. Removing dams, culverts, and barriers from European rivers improves yellow-eel habitat access. Organizations such as the Atlantic Salmon Trust and country-level river trusts do this work and benefit eels alongside other catadromous and anadromous fish.
• Engage with CITES enforcement. CITES decisions are made at intergovernmental Conferences of the Parties. The next CITES CoP will revisit the Anguilla anguilla Appendix II listing and may consider an Appendix I uplisting (full commercial-trade prohibition); civil-society engagement matters here.

Last verified: 2026-05-23 Conservation status: Critically Endangered (IUCN Red List 2020 assessment); CITES Appendix II since 2009; EU commercial export suspension since 2010.

References

• European Commission (2010). Suspension of import and export of Anguilla anguilla. Commission Regulation (EU) No 1158/2010.
• European Council (2007). Council Regulation (EC) No 1100/2007 establishing measures for the recovery of the stock of European eel.
• Europol (2023). Operation Lake VIII press release. https://www.europol.europa.eu/
• Europol/EU SOCTA (2021). EU Serious and Organised Crime Threat Assessment 2021 — Environmental Crime chapter.
• Europol/Eurojust (2019). Glass eels trafficking — annual operations summary.
• ICES (International Council for the Exploration of the Sea) (2024). European eel (Anguilla anguilla) stock advice. https://www.ices.dk/
• Pew Charitable Trusts (2020). Illegal European Eel Trade Continues to Threaten Species' Survival. https://www.pewtrusts.org/
• Pike, C., Crook, V., & Gollock, M. (2020). Anguilla anguilla. IUCN Red List of Threatened Species. e.T60344A152845178.
• Schmidt, J. (1923). The breeding places of the eel. Philosophical Transactions of the Royal Society B 211: 179–208.
• Stein, F. M., Wong, J. C. Y., Sheng, V., et al. (2016). First genetic evidence of illegal trade in endangered European eel from Europe to Asia. Conservation Genetics Resources 8: 533–537.
• Sustainable Eel Group (2024). Sustainable Eel Standard. https://www.sustainableeelgroup.org/
• Tesch, F.-W. (2003). The Eel. 5th edition (Thorpe, J. E., Ed.). Blackwell Science.
• Tomkiewicz, J., Politis, S. N., Sørensen, S. R., et al. (2019). European eel — an integrated approach to establish eel hatchery technology. In Eels: Biology, Monitoring, Management, ed. K. Tsukamoto & M. Kuroki, Springer.