Decades of selective breeding have transformed farmed salmon's genetics, improving production traits but creating welfare trade-offs. Understanding these relationships helps evaluate salmon aquaculture welfare claims.
Selective breeding in salmon is a double-edged welfare tool. Decades of selection for rapid growth has created fish with skeletal problems and metabolic vulnerabilities, similar to welfare problems seen in fast-growing broiler chickens. Cataracts are common in farmed salmon, causing pain and impairing function. At the same time, breeding programs are now explicitly incorporating welfare traits including disease resistance, reduced aggression, and survival under pathogen challenge. This represents a recognition that genetics is a primary lever for welfare improvement at the population scale. The challenge is ensuring welfare traits receive sufficient weight in selection programs alongside commercially driven production traits.