Esox lucius is a voracious predator that inhabits freshwater streams and lakes of most of the northern hemisphere (i.e., North America, north of Europe, and north of Asia). E. lucius' cannibalistic nature since early stages makes it unsuitable for intensive farming because survival is low even with plenty of food, and the use of live prey (sometimes in polyculture systems) increases production costs. LARVAE and FINGERLINGS are primarily produced for stocking of natural populations, with an optimal harvest size of 7-10 cm (2-5 g) or 4-6 cm to avoid cannibalism. A second use is as predator in polyculture pond systems to suppress commercially less valuable cyprinid species to benefit Cyprinus carpio. Reproduction in captivity is achieved in conditions similar to natural ones as well as with hormonal induction of maturation. Although E. lucius only migrates to spawning grounds, its use of space can be quite large, therefore captive conditions will negatively impact its welfare. Additionally, E. lucius is stressed when in captive conditions and when handled, suffers from malformations both in captivity and in the wild, and there is no stunning and slaughter method implemented specifically for it. All these facts make of E. lucius an undesirable candidate for aquaculture.
