Pikeperch (Sander lucioperca) is a priority species for diversifying European inland aquaculture, but juvenile supply is limited by low and unstable survival, cannibalism, and deformities during the larval stage. Colchen et al. (2020) combined three multifactorial experiments and a validation trial in 700 L recirculating-aquaculture-system (RAS) tanks to identify a favourable combination of twelve husbandry factor modalities (initial density 100 larvae/L, no sorting of jumper fish, no sibling population, eggs from large females, discontinuous feeding, no co-feeding, 50 lx light intensity, weaning starting 16 days post-hatching, weaning duration 9 days, 100% per hour water renewal, morning tank cleaning, bottom-up water current), validated with survival 16.9 ± 1.7%, specific growth rate 15.1 ± 5.9% per day, final body weight 815.64 ± 95.34 mg, swim-bladder inflation 92.6 ± 3.2%, FCR 0.65 ± 0.02, and biomass 9.55 ± 0.23 kg per tank. The authors explicitly posed the unresolved question of extending, adapting, and generalizing this protocol, which was derived under voluntarily fixed conditions. Rotifer-based first feeding has been evaluated at production scale with cost accounting, and constant longer-photophase photoperiods have been tested with mixed outcomes, but no study has tested the twelve-factor protocol's robustness across rearing systems, broodstock cohorts, or commercial farms, nor ontogeny-matched progressive abiotic regimes, nor its farm-level transfer. The open problem is the reliable generalization and commercial transfer of the validated protocol.

Background

Pikeperch (Sander lucioperca) is a large freshwater percid fish prized for its white, bone-light flesh, and it is considered one of the best candidates for diversifying inland fish farming in Europe, where wild catches have fallen sharply. Most juvenile production now aims at recirculating aquaculture systems (RAS), i.e. closed indoor facilities in which water is mechanically and biologically filtered and reused, allowing year-round production independent of climate. The bottleneck of the whole production chain is the larviculture stage, the rearing of larvae from hatching to the juvenile stage. Two processes dominate the losses: first, larvae must gulp air at the water surface to inflate their swim bladder (the gas organ that lets fish control buoyancy); failed swim-bladder inflation causes swimming and feeding problems and skeletal deformities, so the inflation rate is a standard quality metric. Second, pikeperch larvae become cannibalistic within weeks, with large individuals ('jumpers') preying on siblings, so size grading is routinely used. Performance is usually reported as survival rate, growth (final body weight, specific growth rate), swim-bladder inflation rate, deformity rate, biomass, and feed conversion ratio (FCR, feed eaten per unit body mass gained). Larvae are first fed on live prey — Artemia nauplii (brine shrimp) or the smaller rotifer Brachionus plicatilis — and then 'weaned', i.e. progressively switched to formulated dry diets; dph denotes days post-hatching. Prior pikeperch larviculture work (compiled in the 2015 reference book Biology and Culture of Percid Fishes) was mostly single-factor experiments with heterogeneous, incompletely reported husbandry conditions, which made results hard to aggregate or transfer to farms. Against this background, Colchen et al. (2020) ran three successive factorial experiments (2015–2017) that varied environmental, feeding, and populational factors simultaneously — a multifactorial design that can estimate interactions between factors, not just single effects — in green 700 L tanks on one pilot-scale RAS, under a fixed 12 h light/12 h dark photoperiod, a 16 to 20 °C temperature ramp, a single Czech-origin broodstock, and commercial diets, followed by a seven-replicate validation trial (2018). This produced the 'twelve-factor protocol': a combination of twelve factor modalities (initial density 100 larvae/L; no sorting of jumpers; no sibling population; eggs from large females; discontinuous feeding; no co-feeding; light intensity 50 lx; weaning beginning at 16 dph; weaning duration 9 days; water renewal 100% per hour; tank cleaning in the morning; bottom-up water current), validated with survival 16.9 ± 1.7%, final body weight 815.64 ± 95.34 mg, specific growth rate 15.1 ± 5.9% per day, swim-bladder inflation 92.6 ± 3.2%, FCR 0.65 ± 0.02, and final biomass 9.55 ± 0.23 kg per tank. Earlier work by Yanes-Roca et al. (2018) had already suggested that introducing the smaller rotifer prey at first feeding could improve pikeperch survival. The open question left by the paper is that the protocol was validated inside one fixed experimental context — tank wall colour, volume and geometry, one broodstock source and management, given commercial diets, a fixed photoperiod and temperature schedule — and its authors state the results could differ if any of these fixed factors were modified, that breeder reproductive traits (age, spawning rank) changed across the three years and may have contributed to the improvement, that progressive adaptation of lighting and temperature to the larvae's sensory (retina) and digestive ontogeny (which develops over the first two months) was suggested but untested, and that know-how transfer to fish farmers has limits that remain unaddressed.

Problem Statement

Colchen et al. (2020) validated a twelve-factor larviculture protocol for pikeperch (Sander lucioperca) in 700 L RAS tanks — initial density 100 larvae/L; no sorting of jumper fish; no sibling population; eggs from large females; discontinuous feeding; no co-feeding; light intensity 50 lx; weaning beginning at 16 dph; weaning duration 9 days; water renewal 100% per hour; tank cleaning in the morning; bottom-up water current — obtaining survival 16.9 ± 1.7%, specific growth rate 15.1 ± 5.9% per day, final body weight 815.64 ± 95.34 mg, swim-bladder inflation 92.6 ± 3.2%, FCR 0.65 ± 0.02, and 9.55 ± 0.23 kg biomass per tank, under voluntarily fixed contextual conditions (green 700 L tanks with fixed geometry, 12L:12D photoperiod, a 16-to-20 °C temperature ramp, one Czech-origin broodstock, given commercial diets). The open problem posed by the source is to extend, adapt, and generalize this protocol into a reliable method for producing pikeperch juveniles at farm level, i.e. to determine, from the existing experimental and field literature and a specified study design: (i) how robust are the validated performances when the fixed environmental and dietary parameters are varied — tank wall colour, tank volume and shape, commercial diets, and non-progressive (constant) photoperiod/temperature variation other than the longer-photophase regimes — so that the protocol can be applied outside its original setting; (ii) how robust is it across broodstock cohorts and genetic strains, with the confounding contribution of breeder reproductive traits (age, spawning rank) disentangled from husbandry effects; (iii) whether progressively adjusted, ontogeny-matched lighting, temperature, or photoperiod schedules (matching the development of the retina, digestive tract, and behaviour) outperform the constant settings; (iv) whether integrating alternative first-feeding prey such as rotifers and longer-photophase photoperiods into the twelve-factor protocol improves performance at production scale; and (v) what operational constraints, labour requirements, and know-how gaps condition the transfer of the protocol to commercial farms, the source noting that the protocol 'has some limits for know-how transfers at the fish farmer level'. These five components are all required and jointly serve one common objective — a reliable, transferable commercial pikeperch larviculture protocol: (i)–(iii) establish which validated settings are robust and which require adaptation, (iv) fixes the first-feeding and photoperiod inputs integrated into the protocol, and (v) establishes operational transfer. For each component, the determination is whether the validated protocol is maintained in the varied context or requires adaptation, and how. A component is maintained when none of the six validated performance metrics the source reported (survival, specific growth rate, final body weight, swim-bladder inflation, FCR, and biomass) moves more than 10% from its validated value in the direction adverse to production, an improvement beyond 10% counts as an improvement rather than a failure to maintain, and a component for which the adverse-direction margin cannot be held requires adaptation.

References

  1. Colchen, T.; Gisbert, E.; Krauss, D.; Ledoré, Y.; Pasquet, A.; Fontaine, P. (2020). Improving pikeperch larviculture by combining environmental, feeding and populational factors. Aquaculture Reports 17, 100337. DOI 10.1016/j.aqrep.2020.100337. https://doi.org/10.1016/j.aqrep.2020.100337
  2. Yanes-Roca, C.; Mráz, J.; Born-Torrijos, A.; Holzer, A.S.; Imentai, A.; Policar, T. (2018). Introduction of rotifers (Brachionus plicatilis) during pikeperch first feeding. Aquaculture 497, 260–268. DOI 10.1016/j.aquaculture.2018.08.004. https://doi.org/10.1016/j.aquaculture.2018.08.004
  3. Imentai, A.; Rašković, B.; Steinbach, C.; Rahimnejad, S.; Yanes-Roca, C.; Policar, T. (2020). Effects of first feeding regime on growth performance, survival rate and development of digestive system in pikeperch (Sander lucioperca) larvae. Aquaculture 529, 735636. DOI 10.1016/j.aquaculture.2020.735636. https://doi.org/10.1016/j.aquaculture.2020.735636
  4. Imentai, A.; Gilannejad, N.; Martínez-Rodríguez, G.; Moyano López, F.J.; Martínez, F.P.; Pěnka, T.; Dzyuba, V.; Dadras, H.; Policar, T. (2022). Effects of First Feeding Regime on Gene Expression and Enzyme Activity in Pikeperch (Sander lucioperca) Larvae. Frontiers in Marine Science 9, 864536. DOI 10.3389/fmars.2022.864536. https://doi.org/10.3389/fmars.2022.864536
  5. Kučera, V.; Pěnka, T.; Malinovskyi, O.; Yanes-Roca, C.; Kuanchaleyev, Z.B.; Policar, T. (2024). Comparative study on the large-scale intensive culture of pikeperch (Sander lucioperca) larvae: Evaluation of two different live exogenous food options. Czech Journal of Animal Science 69(6), 243–254. DOI 10.17221/42/2024-CJAS. https://doi.org/10.17221/42/2024-CJAS
  6. Panana, E.; Deceuninck, G.; Teerlinck, S.; Adriaens, D. (2023). Effect of photoperiod regime on the growth performance, survival, swim bladder inflation and vertebral anomalies of pikeperch (Sander lucioperca) larvae in recirculating aquaculture systems (RAS). Journal of Applied Aquaculture 36, 574–592. DOI 10.1080/10454438.2023.2290705. https://doi.org/10.1080/10454438.2023.2290705
  7. Bischoff, A.A.; Kubitz, M.; Ballesteros-Redondo, L.; Stüeken, M.; Rapp, T.; Fink, P.; Hagen, W.; Palm, H.W. (2023). Dynamics of Fatty Acids in Pikeperch (Sander lucioperca) Larvae and Juveniles during Early Rearing and Weaning in a Commercial RAS—Implications for Dietary Refinement. Fishes 8(9), 444. DOI 10.3390/fishes8090444. https://doi.org/10.3390/fishes8090444
  8. Ballesteros-Redondo, L.; Palm, H.W.; Bährs, H.; Rapp, T.; Stuecken, M.; Wacker, A.; Bischoff, A.A. (2023). Growth and fatty acid composition of pikeperch (Sander lucioperca L., 1758) larvae under altered feeding protocol including the copepod Apocyclops panamensis (Marsh, 1913). Scientific Reports 13, 19574. DOI 10.1038/s41598-023-46988-y. https://doi.org/10.1038/s41598-023-46988-y
  9. Franz, G.P.; Stüeken, M.; Höhne, C.; Grunow, B. (2025). Overlap of vertebral development and first gradings during pikeperch (Sander lucioperca) rearing: implications for possible temporal protocol adaptations. Aquaculture International 33, 522. DOI 10.1007/s10499-025-02208-0. https://doi.org/10.1007/s10499-025-02208-0
  10. Lavajoo, F.; Falahatkar, B.; García-Meilán, I.; Perelló-Amorós, M.; Efatpanah, I.; Gutierrez, J. (2023). Ontogeny of the digestive enzyme activity of the pikeperch (Sander lucioperca) under culture condition. Scientific Reports 13, 19739. DOI 10.1038/s41598-023-43845-w. https://doi.org/10.1038/s41598-023-43845-w
  11. Olin, M.; Kotakorpi, M.; Nurminen, L.; Ruuhijärvi, J. (2021). The maternal effects on Pikeperch (Sander lucioperca) larvae depend on temperature. Ecology of Freshwater Fish 31, 280–290. DOI 10.1111/eff.12629. https://doi.org/10.1111/eff.12629
  12. Ljubobratović, U.; Demény, F.; Peter, G.; Malinovskyi, O.; Kwiatkowski, M.; Pataki, B.; Horváth, Á. (2022). Can artificial reproduction strategies (hormonal type and dose/thermal regime) affect gamete quality in indoor-reared pikeperch (Sander lucioperca)? Aquaculture Reports 23, 101032. DOI 10.1016/j.aqrep.2022.101032. https://doi.org/10.1016/j.aqrep.2022.101032
  13. Pourhosein-Sarameh, S.; Falahatkar, B. (2024). Pikeperch (Sander lucioperca) adaptive or maladaptive reactions to environmental stressors: a review. Aquaculture International 32, 6539–6573. DOI 10.1007/s10499-024-01478-4. https://doi.org/10.1007/s10499-024-01478-4
  14. Pěnka, T.; Tellbüscher, A.A.; Mráz, J.; Policar, T.; Roy, K. (2025). Aquaculture nutrition of perch and pikeperch: An analysis for European percid aquaculture. Aquaculture 606, 742589. DOI 10.1016/j.aquaculture.2025.742589. https://doi.org/10.1016/j.aquaculture.2025.742589
  15. Kestemont, P.; Dabrowski, K.; Summerfelt, R.C. (eds.) (2015). Biology and Culture of Percid Fishes. Springer. DOI 10.1007/978-94-017-7227-3. https://doi.org/10.1007/978-94-017-7227-3