Atlantic-origin gilthead seabream shows trend towards better growth and feed conversion than Mediterranean lines

A study carried out under commercial sea cage farming conditions suggests that Atlantic-origin gilthead seabream (Sparus aurata) may show productive advantages over Mediterranean lines, particularly in terms of growth and feed efficiency.

The research, conducted over 15 months at a marine farm in Candarli Bay, Türkiye, compared two gilthead seabream populations – one of Atlantic origin and one over Mediterranean origin – reared under the same environmental and feeding conditions.

Atlantic-origin fish reached a mean final weight of 415 grams, compared with 374 grams in the Mediterranean group. The also showed a better feed conversion ratio, with a FCR of 1.79 compared with 1.92, as well as a higher specific growth rate.

However, the authors warn that these differences should be interpreted with caution. Although the results were initially significant, they were no longer statistically significant after applying False Discovery Rate correction for multiple comparisons. The study therefore does not allow a definitive conclusion that Atlantic line are superior, but it does identify a consistent trend that could be relevant for future selective breeding programmes.

Genetics and production efficiency

The study also analysed the genetic diversity of both populations using microsatellite markers and RAPD-PCR. The results showed moderate genetic differentiation between the Atlantic and Mediterranean groups, as well as greater genetic variability in the Atlantic population.

According to the researchers, this diversity could be linked to greater adaptative capacity and higher production potential under certain farming conditions.

The work reinforces an increasingly relevant line of research in Mediterranean aquaculture: the role of stock genetic origin in production efficiency, feed conversion and animal resilience.

Despite the observed differences in growth and lipid metabolism, survival rates were similar in both populations, at around 85-88%.

Histological analysis detected greater lipid accumulation in the liver and internal organs of the Mediterranean line, although no significant physiological differences were found between the groups.

Implications for Mediterranean breeding

Although the study does not provide definitive evidence, it raises a question of interest for hatcheries, producers and genetic improvement programmes in Europe: to what extent could certain Atlantic lines offer productive advantages in intensive gilthead seabream farming systems?

The researchers consider that these results need to be validated through multigenerational trials, testing across different production environments and higher-resolution genomic tools.

In a context of pressure on costs, feed efficiency and competitiveness, the study suggests that the selection of genetic origin could become an increasingly strategic variable for improving the productive performance of gilthead seabream.