Decades of selective breeding for rapid growth in farmed salmon have produced fish with health vulnerabilities that create significant welfare challenges in aquaculture systems.
The salmon farming industry has optimized for production metrics — growth rate, feed conversion, disease resistance — while welfare consequences accumulated as secondary concerns. Fish bred for maximum growth carry biological burdens their wild counterparts never evolved to bear: oversized muscles straining skeletal systems, hearts working beyond their capacity, immune systems overloaded. This represents a fundamental tension in intensive aquaculture — the animals most profitable to raise are often those experiencing the greatest chronic health burden. Addressing this requires welfare criteria to be built into breeding programs alongside production traits.