European sea bass (Dicentrarchus labrax) is one of the most valuable farmed fish in the Mediterranean, with significant production in Greece, Turkey, Italy, Spain, and Croatia. As global seafood demand grows and capture fisheries face pressure, farmed sea bass production is expandingāmaking welfare science increasingly important.
Sea bass are predatory, active fish requiring substantial swimming space and varied environmental stimulation. Wild sea bass occupy structured coastal habitatsāseagrass beds, rocky reefsāand display complex social hierarchies. In aquaculture, they are typically farmed in open sea cages at high densities with limited environmental enrichment. Their stress physiology (cortisol, immune markers) responds sensitively to handling, crowding, and water quality.
Stocking density: Commercial sea bass densities of 15-25 kg/mĀ³ exceed levels shown to cause chronic stress in research settings. Optimal welfare density is estimated at 8-15 kg/mĀ³. Crowding during harvest: Pursing net harvest concentrates fish to extreme densities, causing severe acute stress. Improved harvest protocols and pre-slaughter crowding minimization are welfare priorities. Sea lice: Caligus parasites cause irritation, tissue damage, and secondary infection. Treatment (chemical or cleaner fish) involves handling stress. Spawning stress: Hormonal manipulation of spawning induces endocrine stress.
Sea bass are often killed by COā immersion or ice slurry without prior stunningāmethods causing prolonged conscious distress. Electrical stunning before killing is technically feasible and increasingly advocated. Some premium producers use live chilling with ice slurry at near-freezing temperatures which reduces (but may not eliminate) consciousness before killing.
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