Fish farming expands food supplies while exposing environmental tradeoffs
Published on 1 November 2026 at 08:27 GMT
By Editorial Team SDG14
Fish supplies protein and micronutrients to diets worldwide, but rising demand increasingly depends on animals raised rather than caught. Fish farming can make supplies more predictable, create employment and supplement wild catches. Its environmental and social results depend on what is farmed, where and how, and who receives the benefits.
The Food and Agriculture Organization of the United Nations (FAO) reported in June 2026 that aquaculture produced an estimated 103 million tonnes of aquatic animals in 2024, against approximately 92 million tonnes from capture fisheries. These totals include shellfish and crustaceans, not just finfish, and exclude algae. Aquaculture accounted for 53 per cent of aquatic animal production.
The historical shift is substantial. FAO records show apparent annual consumption rising from 9.1 kg per person in 1961 to 20.6 kg in 2021. Apparent consumption measures food availability rather than actual individual intake. Capture output has remained within approximately 86–94 million tonnes since the late 1980s; aquaculture has supplied nearly all subsequent production growth. FAO projects total aquatic animal output of 214 million tonnes by 2034, a forecast rather than an observed result.
Different farms different outcomes
Aquaculture includes a wide range of production systems. Asian freshwater ponds, including carp polyculture, differ from salmon cages in Norway or Chile and indoor recirculating tanks. Low-input ponds draw on natural productivity; more intensive farms use supplementary or formulated feeds and more controlled stocking. Even within one species, water exchange, farm density and local regulation alter outcomes.
Scheduled stocking and harvesting can make supplies more predictable than reliance on daily wild catches. Selective breeding, vaccines and improvements in feeding and husbandry have expanded control over production. Nevertheless, farms remain vulnerable to disease and environmental shocks. Contracts for regular deliveries do not eliminate the risk of mortality or interrupted production.
Efficiency also has several meanings. Feed conversion measures feed used per unit of growth, whereas edible yield, energy consumption and nutrient losses answer different questions. A farm producing more fish per hectare may simultaneously use more electricity. Comparisons that report only one measure can obscure costs elsewhere in the production chain.
Feed connects farms to land and sea
Rosamond Naylor and colleagues’ 2021 review documented improved feed efficiency between 1997 and 2017, alongside continuing dependence on marine ingredients and increased reliance on terrestrial crops. Fishmeal and fish oil can come from wild fisheries or processing by-products; plant ingredients bring land and resource demands. Dependence varies by species and diet. Salmon and herbivorous carp do not have identical nutritional requirements.
Whether farmed fish relieve pressure on a particular wild population depends partly on substitution. Additional farm output can replace purchases of wild fish, but can also meet additional demand. If feed uses wild fish, another fishery remains involved. Consequently, rising aquaculture production alone does not establish that fishing mortality has fallen in any particular stock.
Pollution disease and welfare
Uneaten feed and excreta can enrich surrounding waters and sediments. Open cages exchange water directly with the environment; ponds can discharge effluent; recirculating systems collect wastes that require treatment or disposal. Escaped fish may compete with wild animals or interbreed with related populations. The consequences depend on species, receiving habitats and escape numbers, rather than on a universal impact shared by all farms.
The World Organisation for Animal Health (WOAH) identifies disease spread through aquatic animal movements as a threat to production. It also warns that antimicrobial misuse and overuse increase resistance risks affecting animal and human health. Antibiotics, antiparasitic treatments and vaccines are different tools; their use cannot be inferred simply from a product being farmed. WOAH standards address antimicrobial stewardship and resistance monitoring.
Animal welfare raises questions beyond whether a fish survives. Water quality, crowding, handling and transport affect stress and injury. WOAH has developed farmed-fish welfare standards covering transport, stunning and killing. These international standards do not themselves demonstrate compliance at an individual farm. Species-specific assessment matters because tolerances and behaviour differ.
Technical changes redistribute risks. Recirculating systems filter and reuse water, but require large amounts of energy and carry high production costs; disease failures can be catastrophic. Offshore cages face storms, strong currents and large capital costs. Naylor and colleagues identified these constraints in 2021. Neither approach is a universal escape from the economic and ecological limitations of farming.
Fishing communities through the transition
Artisanal capture fishing and aquaculture are distinct activities, and both can operate at small scales. Artisanal fisheries typically involve relatively small production units and locally embedded livelihoods, although definitions vary between countries. Fishing and farming can coexist within households and regions. Their development cannot be reduced to small boats being replaced by large farms.
Engines, ice, refrigeration and market connections influence how catches reach consumers. Aquaculture also supports hatchery, husbandry, processing and technical jobs. Yet employment totals cannot reveal whether a particular household gains secure income, loses access to fishing grounds or takes on debt. Changes in living conditions depend on ownership, wages, market access and resource rights.
The FAO Illuminating Hidden Harvests initiative documents how limited information can marginalise small-scale fisheries in policy decisions. This complicates comparisons with readily measured commercial farm output. Higher production and export earnings do not automatically describe improvements in fishing communities’ housing, services or bargaining power. FAO also reports persistent gender inequalities across aquatic food employment.
Finance creates another dividing line. Feed purchases, juveniles, electricity and disease losses affect operating costs; advanced systems add substantial investment requirements. A technology that works biologically may remain commercially inaccessible to a small producer. Conversely, export-oriented output cannot be treated as equivalent to affordable food available locally.
Coexistence under specific conditions
Farms can expand supplies while capture fisheries retain nutritional, economic and cultural roles. Outcomes vary with feed sourcing, waste control, disease prevention, containment and access to shared waters. Marine pollution, biodiversity and access to marine resources connect these issues to SDG 14 (Life below water).
FAO promotes science-based governance and spatial planning for aquaculture alongside stronger capture-fisheries management. Assessing expansion therefore involves measuring environmental performance and how costs and benefits are distributed. Production growth records the quantity harvested; it does not, by itself, establish improvements in either.
Written by a human author, edited with AI assistance.
Further information:
FAO SOFIA 2026 release. Supports 2024 production estimates, the historical capture plateau, the 2034 forecast and governance positions.
FAO SOFIA 2024 release. Supports historical consumption, nutritional context and employment inequalities.
Naylor and colleagues 2021. Reviews species and systems, feed changes during 1997–2017, environmental risks and technical constraints.
FAO Illuminating Hidden Harvests. Explains the evidence gaps and policy marginalisation affecting small-scale fisheries.
World Organisation for Animal Health. Supports disease, antimicrobial resistance and farmed-fish welfare coverage.
