Introduction
Pikeperch (Sander lucioperca) is a valuable aquaculture species with a steadily increasing market demand (Policar et al. 2016). Most pikeperch originating from intensive culture are intended for market-size production. Nevertheless, pond aquaculture is becoming increasingly interested in stocking material produced in recirculating aquaculture systems (RAS), mainly due to predictable production and logistical advantages. However, differences in rearing environments, such as RAS versus traditional pond culture, may significantly impact swimming capabilities and behavior in general, which are critical as a foundation for predatory efficiency and effective escape responses (Khendek et al. 2017). These traits are important for survival, influencing both pond aquaculture success and the effectiveness of restocking programs into natural habitats as in both scenarios fish is exposed to natural complex environment and conditions close to them (Juza et al. 2024). This study investigates how distinct rearing conditions influence the swimming performance of pikeperch, with particular emphasis on traits supporting predatory capacity and escape reflexes.
Material and methods
Pikeperch with an average body weight of 30 g, originating from two different rearing systems — recirculating aquaculture systems (RAS) and traditional pond culture — were used for the study. Prior to the swimming performance trials, fish were acclimated for two days to the experimental environment under controlled conditions. Swimming activity was assessed over a three-day period for each repetition. The trials were conducted in three identical flow arenas, allowing simultaneous testing of multiple individuals. Each experimental set consisted of three repetitions. Fish swimming behaviour was continuously recorded using infrared cameras, enabling observation during both day and night without disturbing the fish. The recorded footage was analysed using EthoVision XT software (Noldus Information Technology), providing detailed quantification of swimming parameters such as velocity, distance travelled, and activity patterns.
Results and discussion
Significant differences in swimming performance were observed between the two groups of pikeperch. Fish differed in average velocity, total distance travelled, and overall activity levels throughout the recording periods. These differences were consistent across all repetitions and were evident during both daytime and nighttime observations.
The variation in swimming performance likely reflects the impact of rearing conditions. Environmental factors such as water movement and habitat complexity during the early stages of development can influence muscular development, stamina, and behavioral patterns. Fish reared under more dynamic conditions may develop enhanced swimming abilities, which can be advantageous for survival after release. These results highlight the importance of considering environmental conditioning in aquaculture practices, particularly for species intended for stocking into natural or semi-natural environments.
Acknowledgements
The study was supported by the CENAKVA.
References
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