Genetic parameters and genotype by environment interactions for growth traits and survival of olive flounder (Paralichthys olivaceus) in recirculating aquaculture system and flow-through system

In recent years, intensive recirculating aquaculture systems (RAS) as an eco-responsible and more efficient aquiculture model have been emerged into practice, and have been taking place of the traditional flow-through systems (FTS). The aim of this study was to estimate genetic parameters for body weight (BW), total length (TL) and survival (SUR) reared in the both environments (i.e. RAS and FTS) in olive flounder, and investigate genotype by environment (G x E) interactions for these traits between RAS and FTS. The heritability estimates for BW and TL were moderate (0.15-0.22) in both environments. For SUR, the heritability was 0.13 +/- 0.05 and 0.19 +/- 0.06 for RAS and FTS respectively. The genetic correlations of BW (0.65 +/- 0.13), TL (0.33 +/- 0.12), and survival (0.40 +/- 0.10) were relatively low between the two rearing environments. The differences in the heritabilities and the low genetic correlations between the two environments suggested that the magnitude of G x E interactions was very high, which showed evidence that there was severe re-ranking of family performance. We concluded that G x E interactions for olive flounder between the two rearing environments were of vital importance. These results will be beneficial for developing breeding programs in olive flounder because the accuracy of selection and genetic gain for growth and survival may differ between rearing environments. Hence, it is necessary to select environment-specific strains in olive flounder. Statement of relevance: This paper offers guidelines to select breeding strategy in olive flounder when fish are reared in different aquaculture systems.