Swim Bladder Welfare in Farmed Fish

Swim bladder disorders are common in farmed fish and cause chronic pain and buoyancy problems that significantly impair welfare. Understanding causes helps guide prevention.

Key Facts

Swim bladder disorders affect up to 30% of some farmed species including zebrafish and carp
Rapid pressure changes during crowding or transport cause barotrauma and swim bladder damage
Overinflation of swim bladders in intensively farmed fish is linked to high feeding rates
Affected fish struggle to maintain normal depth, causing chronic muscular effort or chronic sinking
Swim bladder disorders cause chronic pain evidenced by behavioural changes and reduced feeding

Welfare Considerations

Fish with swim bladder disorders cannot control their buoyancy, causing them to float unnaturally at the surface or sink to the bottom. Maintaining position against abnormal buoyancy requires constant muscular effort that is exhausting. Affected fish reduce feeding, show abnormal posture, and are more vulnerable to predation in natural settings. The chronic effort of swimming against buoyancy problems is painful and debilitating. Swim bladder damage is largely invisible to farmers monitoring surface behaviour, meaning many affected fish suffer without detection or treatment.

What You Can Do

Support aquaculture welfare standards that include swim bladder disorder monitoring
Choose farmed fish from producers using lower-stress handling and crowding protocols
Donate to fish welfare research on swim bladder disorder prevention and treatment
Advocate for swim bladder health inclusion in aquaculture welfare assessment frameworks
Engage with aquaculture retailers about swim bladder welfare monitoring in their supply chains