The European eel (Anguilla anguilla) is a critically endangered species experiencing catastrophic population decline while simultaneously being farmed and fished at substantial scale. The convergence of conservation emergency and commercial exploitation creates a complex ethical and welfare context unique in European fisheries.
European eel populations have declined by over 90% since the 1980s — one of the most severe declines of any commercially exploited species. A complex life cycle (spawning in the Sargasso Sea, 4,000-7,000km distant from European rivers) makes the species extremely vulnerable to any disruption: barriers to migration (dams and weirs), water quality deterioration, climate change effects on ocean currents and temperature, the swim bladder parasite Anguillicoloides crassus (introduced from Asia), and overfishing all contribute to decline. The species is classified as Critically Endangered on the IUCN Red List.
European eel aquaculture relies entirely on wild-caught glass eels (juvenile eels migrating from sea to freshwater) for stocking, as captive reproduction has not been achieved commercially. This creates a direct conflict: eel farming draws on the already depleted wild glass eel stock. Annual glass eel quotas, catch limits, and restocking obligations (requiring proportion of farmed glass eels to be returned to rivers) attempt to balance commercial interests with conservation needs.
European eel farming raises specific welfare concerns: High stocking densities in intensive recirculating systems may cause chronic stress; Aggression — eels are cannibalistic and territorial, requiring size grading to prevent predation of smaller individuals; Oxygen management — eels can extract oxygen from both water and air but crowded systems require careful oxygen management; Disease — bacterial (Aeromonas, Pseudomonas) and parasitic diseases cause welfare harm; Harvesting — traditional harvesting methods may involve prolonged suffering if inappropriate.
European eels are traditionally killed by live immersion in salt (osmotic shock) — a method that causes significant suffering before death and is increasingly recognised as unacceptable. Welfare-conscious alternatives include electrical stunning before killing, percussive stunning, or CO2 narcosis before killing. The development and adoption of humane killing methods for eels is a welfare priority, and some processors have adopted better methods in response to retailer standards and evolving regulatory guidance.
Several conservation measures for wild eels align with welfare concerns: improving fish passage at barriers (reducing injury and mortality during upstream and downstream migration), restoring wetland habitats, reducing barriers to natural eel recruitment, and decreasing pressure on wild eel populations from commercial fishing. Supporting wild population recovery reduces both the conservation crisis and the ethical problems of farming a critically endangered species.
Long-term solutions require: reducing commercial reliance on wild glass eels through genuine captive reproduction research (the holy grail of eel aquaculture), reducing total eel exploitation to levels compatible with population recovery, improving welfare standards in existing eel farming operations, and developing market products that explicitly support conservation (e.g., eel farmed using legally sourced glass eels with restocking obligations fulfilled). The European eel situation exemplifies the tensions between commercial exploitation, conservation, and welfare that increasingly characterise fisheries management.