Scale of Aquaculture
Aquaculture (fish and shellfish farming) is the world's fastest-growing food production sector, now supplying over half of all fish consumed globally. It involves hundreds of billions of individual fish and trillions of crustaceans and shellfish annually — numbers that dwarf land animal agriculture in individual count.
>50%
Of global seafood now from aquaculture
~120M tonnes
Annual aquaculture production
Trillions
Shrimp farmed annually (count)
>73B
Fish slaughtered in aquaculture/yr (est.)
Welfare Issues in Finfish Aquaculture
Crowding and Stocking Density
Commercial fish farms operate at high stocking densities that bear no resemblance to natural population densities. Atlantic salmon farms in Norway may hold 20–25 kg of fish per cubic metre of water. At these densities:
- Fish cannot engage in normal swimming patterns or schooling behaviour
- Dominant individuals have priority access to food; subordinate fish are chronically stressed
- Parasites (especially sea lice in salmon) spread rapidly through dense populations
- Aggression and fin damage are common
Disease and Parasites
Sea lice — copepod parasites — are a massive welfare problem in Atlantic salmon aquaculture. They feed on fish skin, scales, and tissue, causing severe lesions, pain, and sometimes death. Treatment involves:
- Chemical treatments: Pesticides (emamectin benzoate, azamethiphos) with welfare side effects
- Thermal delousing: Bathing fish in hot water (28-34°C) — extremely stressful and causes mortality
- Mechanical delousing: Machines that brush off lice — causes scale damage and stress
- Cleaner fish: Wrasse and lumpsuckers deployed as biological controls — often themselves kept in poor welfare conditions
Sea lice crisis: Sea lice resistance to treatments is growing. Norwegian salmon farms lose hundreds of millions of salmon to sea lice-related mortality annually. The welfare and economic costs are enormous — yet the industry continues to expand.
Slaughter Methods
Most farmed fish are killed by methods that cause significant suffering:
- Asphyxiation in air: Allowing fish to suffocate — can take 15+ minutes
- Ice slurry: Fish placed in ice and water — causes cold shock but fish remain conscious for some time
- CO2 narcosis: Causes distress before unconsciousness; not universally accepted as humane
- Percussive stunning + bleed: More humane; increasingly required by welfare certifications
- Electrical stunning: Being developed; reduces conscious time before death
Shrimp Welfare
Farmed shrimp are produced in enormous numbers — hundreds of billions annually. Welfare standards are virtually nonexistent. Key issues:
- Eyestalk ablation: Female shrimp have one eyestalk removed to trigger reproductive maturation — a painful mutilation performed without anaesthesia across the industry
- Extreme crowding: Intensive ponds hold shrimp at densities far exceeding natural populations
- Disease: Early Mortality Syndrome (EMS) and white spot disease have devastated shrimp production with catastrophic mortality events
- Water quality: Poor oxygen levels and ammonia accumulation cause chronic stress
- Slaughter: Typically by ice immersion — whether shrimp experience pain in a morally relevant sense is debated, but evidence supports at least some form of nociception
Shrimp Welfare Project: An organisation specifically focused on improving welfare for farmed shrimp — currently among the most tractable high-impact animal welfare interventions given the enormous numbers involved and near-zero current welfare standards.