The European eel (Anguilla anguilla) is a high-value species for commercial aquaculture in Europe, where wild-caught glass eels (transparent juveniles) are stocked in grow-out facilities to be cultured for human consumption or restocking purposes (FAO, 2023). However, the species has been categorized as “critically endangered” with the natural population at a historical low (Pike et al., 2020). Consequently, eel aquaculture requires closing the life cycle in captivity and efficient hatchery technology and techniques. Targeting this goal, developed broodstock feeds and assisted reproduction protocols, applying hormone therapy, have enabled a stable production of high-quality gametes and viable offspring (Tomkiewicz et al., 2019), while recent research has focused on the development of feeds and culture methodology for offspring (Politis et al., 2021; Benini et al., 2023; Bandara et al., 2024). This has led to larval growth and development into the leptocephalus stage (Fig. 1) incrementally extending longevity. Still, limited growth and high mortality in the early larval stages challenge the completion of this phase.
This presentation will overview progress in European eel larval culture and discuss bottlenecks needing attention to reach metamorphosis and glass eel stage in high numbers. Among other, we look at the still limited insights in larval demands to ambient culture conditions and stage specific nutritional requirements and preferences, but also the demands for an efficient hatchery operation and closed-cycle production of European eel.
References
FAO, 2023. www.fao.org/fishery/en/culturedspecies/anguilla_anguilla/en
Pike C, Crook V, Gollock M, 2020. Anguilla anguilla. The IUCN Red List of Threatened Species, 2020. https://doi.org/10.2305/IUCN.UK.2020-2.RLTS. T60344A152845178.en.
Tomkiewicz J, Politis S, Sørensen S, Butts I, Kottmann J, 2019. European eel – an integrated approach to establish eel hatchery technology in Denmark. In: Eels Biology, Monitoring, Management, Culture and Exploitation: Proceedings of the First International Eel Science Symposium, 2019. 5m Publishing, Sheffield, UK.
Politis SN, Syropoulou E, Benini E, Bertolini F, Sørensen SR, Miest JJ, Butts IAE, Tomkiewicz J, 2021. Performance thresholds of hatchery produced European eel larvae reared at different salinity regimes. Aquaculture 539, 736651.
Benini E, Bandara KA, Politis SN, Engrola S, Nielsen A, Conceiçao LEC, Santos A, Sørensen SR, Tomkiewicz J, 2023. Exploring first-feeding diets for European eel larval culture: insights at morphological, nutritional, and molecular levels. PLoS One 18, e0283680.
Bandara KA, Politis SN, Sørensen SR, Benini E, Tomkiewicz J, Vadstein O, 2024. Effect of Food Amounts on Larval Performance, Bacteriome and Molecular Immunologic Development during First-Feeding Culture of European Eel. Microorganisms, 12(2), 355.