Genetic parameters and genotype by environment interaction for production traits and organ weights of gilthead seabream (Sparus aurata) reared in sea cages

Gilthead seabream is a key fish species for farming in the Mediterranean region and farmed large geographical area under various production circumstances. However, more than 80% of genetically improved fingerlings originate from single country, Greece, which poses potential risk genotype by environment interaction (GxE). Therefore, objective this study was to quantify GxE several traits gilthead two distinct commercial sites, one south Greece (Galaxidi Marine Farm) another southeast Spain (Cudomar). For experiment, population juveniles produced mass spawning 33 males 20 females on day. These were stocked sea cages both locations when they reached stocking size (~3 g) grown conditions. Management conditions during grow-out period kept same between while subject naturally occurring differences such as water temperature, dissolved oxygen, salinity. Phenotypes recorded harvest (~400 g). Genetic parameters estimated using genomic relationship matrix that built ~30 k SNP. All studied had higher genetic variation heritabilities Cudomar. instance, heritability weight 0.37 ± 0.05 Galaxidi 0.55 correlations trait measured different environments. Moderate found (0.45 0.11), growth (0.43 fillet (0.49 0.12), liver (0.61 viscera (0.62 0.10). Weak fat (0.87 0.06), heart (0.76 cardiosomatic index (0.93 0.14), viscerosomatic (0.90 0.05), hepatosomatic (0.79 0.09). In conclusion, moderate estimates indicate with breeding program, performance data environments should be included, or separate programs may needed The variances observed Cudomar suggest suitable test selective breeding. • growth, weight, sites percentage Heritabilities all larger (Spain).