Genetic Traceability of European Sea Bass (Dicentrarchus labrax) and Gilthead Seabream (Sparus aurata) for Technological Advancements in Breeding Management

Abstract

This study evaluated the genetic variability and traceability potential of farmed European sea bass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) populations from a fish farm located in Petrosino (Marsala, Sicily) (FAO 37), using microsatellite markers. A total of 64 D. labrax and 63 S. aurata individuals were genotyped with species-specific multiplex panels (9 and 10 loci, respectively). High levels of polymorphism were observed in both species, with an average of 12 alleles per locus in D. labrax and 9.1 alleles per locus in S. aurata. Mean observed heterozygosity (Ho) was 0.530 in D. labrax and 0.459 in S. aurata, while expected heterozygosity (He) reached 0.762 and 0.702, respectively. The fixation index (F) indicated moderate heterozygote deficiency in both populations (0.320 in D. labrax and 0.352 in S. aurata). Significant deviations from Hardy–Weinberg equilibrium were detected at most loci in both species, suggesting non-random mating, genetic drift, or population substructure. The probability of identity (PI) values across loci confirmed the high discriminatory power of the microsatellite panels, supporting their suitability for individual identification and genetic traceability applications in aquaculture. Overall, the results highlight that, despite substantial genetic variability, the observed heterozygote deficiency and deviations from equilibrium may reflect suboptimal breeding management practices. These findings underline the importance of implementing regular genetic monitoring and integrating molecular tools into broodstock management to maintain genetic diversity, reduce inbreeding, and support sustainable aquaculture production.

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