Salmon Genetics and Welfare: How Selective Breeding Affects Fish Health

Decades of selective breeding in Atlantic salmon has produced faster-growing fish with compromised immune function and increased vulnerability to disease — a welfare consequence of production optimization.

Key Facts

Selective breeding has increased Atlantic salmon growth rates by over 200% since the 1970s
Faster-growing farmed salmon have higher rates of skeletal deformity, cataracts, and heart problems
Heart and skeletal muscle inflammation (HSMI) is a significant welfare and production problem in farmed salmon
Disease-resistant salmon strains are being developed but face regulatory hurdles in some markets
Trade-offs between growth rate and welfare traits are being increasingly recognized by the industry

Welfare Considerations

The salmon genetics story is a cautionary tale about production optimization at the expense of animal welfare. Decades of selection for rapid growth produced fish that grow faster but suffer more — higher rates of skeletal abnormalities, organ problems, and disease susceptibility. This is not inevitable: selection programs that explicitly incorporate health and welfare traits alongside production traits can produce fish that grow well and suffer less. The barrier is primarily the short-term thinking of production systems that externalize welfare costs.

What You Can Do

Support aquaculture certification programs that include genetic welfare criteria
Advocate for regulatory requirements for health and welfare monitoring in salmon breeding programs
Back research into salmon breeding programs that explicitly select for welfare-positive traits
Reduce farmed salmon consumption or choose certified products with welfare standards
Support mandatory reporting of abnormality rates and disease incidence in salmon farming