European eel aquaculture is based entirely on wild-caught glass eels, raising both conservation and welfare concerns throughout the production cycle.
Eel aquaculture welfare is inseparable from conservation concern, as every farmed eel represents a wild-caught individual removed from an already critically depleted population. High-density rearing in RAS causes chronic stress with stereotypic behavior including persistent surface swimming. Handling during grading causes acute stress and injury risk given the eel's elongated body. Slaughter of eels requires attention as their robust physiology means delayed loss of consciousness with some methods. The absence of captive breeding means that improving eel aquaculture welfare cannot compensate for the wild population impact. The most welfare-positive outcome for the species may be elimination of eel farming rather than improvement of farming conditions.