Case study on the aptness of in-pond raceways for pikeperch, Sander lucioperca, grow-out

Pikeperch Sander lucioperca is a species of increasing presence in recirculation aquaculture system and the vast majority of thus far research was dedicated to its indoor farming. Concerning the present pond infrastructure in Central and East Europe, it is of interest to evaluate the intensive pond-connected system for pikeperch rearing. Therefore, the present study evaluated the grow-out performance in recirculation aquaculture system (RAS) and in-pond-raceway (IPR) in triplicated tanks. A 16-week trial with 1-year-old pikeperch (mean weight 215.7 +/- 8.1 g RAS and 217.7 +/- 2.6 g IPR) was conducted from June to October evaluating both culture and welfare pa-rameters. Significantly higher final mean weight (443.1 +/- 17.5 vs 400.6 +/- 13.2) and lower feed conversion (2.1 +/- 0.1 vs 3.0 +/- 0.1) was obtained in fish reared in IPR. Cortisol levels were overall higher in the RAS group throughout the trial being significantly higher at the first and last sampling. Elevated lysozyme levels were found in IPR in the first half of the trial, while further on they were higher in RAS being significantly higher compared to IPR in middle sampling. Thus, both in terms of culture performance and fish welfare, IPR proves aptness for pikeperch rearing. This study presents the first insight into the suitability of pond-connected intensive rearing of pikeperch describing IPR as a promising system for final grow-out during the growing season. More compre-hensive studies in terms of stocking densities and growing period are required to explore the full potential of pikeperch outdoor farming.