Sea trout (Salmo trutta — the same species as brown trout, with a migratory sea-running life form) are farmed at a much smaller scale than rainbow trout or Atlantic salmon but represent an important niche product in UK and Scandinavian aquaculture. Their welfare needs share much with other salmonids but have specific characteristics worth understanding.
Brown trout and sea trout are the same species exhibiting different life history strategies. In aquaculture, both forms may be produced, typically in flow-through river-fed systems or small-scale RAS. Sea trout are generally less intensively farmed than rainbow trout, with production systems that often reflect more traditional, lower-density approaches. Their welfare challenges are broadly similar to rainbow trout but with some differences in stress physiology related to their anadromous (sea-migratory) background.
As for rainbow trout, electrical stunning followed by percussive killing or spiking is the welfare-preferred slaughter method. CO2 immersion is aversive and should be avoided where alternatives are available. The small scale of most brown/sea trout operations means that slaughter is often performed on-site rather than in large processing facilities, with variable welfare standards.