Evaluation of the stock enhancement effect of Korean Rockfish Sebastes schlegelii with molecular markers in the Haiyang sea area

Objective This study aimed to evaluate the efficacy of Korean Rockfish Sebastes schlegelii stock enhancement in the Haiyang coastal waters (Shandong Peninsula) during 2023–2024 using molecular markers, including microsatellite loci and mitochondrial DNA sequences. The goal was to assess the contribution of released individuals to the local population and provide novel perspectives for sustainable fishery management. Methods The analysis utilized ‌412 broodstock samples‌ collected from the Haiyang sea area and ‌424 recaptured individuals‌ from four sampling events (July–October 2024). Genetic diversity was quantified via eight microsatellite loci, measuring allele counts, observed heterozygosity, and expected heterozygosity. Parentage analysis combined simple sequence repeat markers and mitochondrial DNA sequences to trace released individuals and their offspring in recaptured samples‌. Results A total of ‌105 alleles‌ were identified across eight loci (average = 13 alleles/locus). The population exhibited high genetic diversity (observed heterozygosity = 0.711 ± 0.109; expected heterozygosity = 0.787 ± 0.060)‌. Among recaptured individuals, ‌40 offspring‌ (linked to ‌37 parents‌) were confirmed as progeny of the 2024-release cohort and no 2023-released individuals were detected, potentially due to low survival rates or insufficient sampling. Conclusions Molecular markers effectively demonstrated that the 2024-released S. schlegelii significantly supplemented the local population’s biomass within the same year‌. However, the absence of 2023-released individuals highlights the need for improved survival monitoring and expanded sampling. Future studies should prioritize tracking interannual population dynamics to optimize long-term fishery sustainability‌.