Salmon Jaw and Skeletal Deformities: Welfare in Aquaculture

Skeletal deformities including jaw malformation and spinal curvature affect a significant proportion of farmed salmon. Understanding causes and prevention is essential for welfare improvement.

Key Facts

Jaw and spinal deformities affect 5-20% of some farmed salmon populations
Causes include genetic factors, nutritional deficiencies, and early rearing conditions
Jaw deformities (shortened or twisted mandibles) impair feeding causing chronic starvation stress
Spinal curvature (lordosis, scoliosis) may impair swimming causing chronic physical discomfort
Deformed fish are typically culled early but suffer during the period before detection
Vitamin C supplementation and improved hatchery conditions reduce deformity rates

Welfare Considerations

Skeletal deformities in farmed salmon cause chronic welfare harm that may persist for extended periods before affected fish are identified and culled. Fish with jaw malformations cannot compete at feeders, experience nutritional stress, and may suffer secondary infections from impaired mucus barriers. Spinal deformities impair hydrodynamic efficiency causing chronic physical strain during swimming. Prevention through nutrition and genetics is the welfare priority; early detection and humane culling minimise suffering duration.

What You Can Do

Support aquaculture welfare certification requiring deformity monitoring and reporting
Advocate for mandatory deformity rate reporting in aquaculture licensing
Choose salmon from farms with documented low deformity rates and early detection protocols