What is overfishing?

It is a serious global problem that threatens ocean wildlife and biodiversity. Loss of marine life brings a further threat to the billions of people who rely on seafood for protein and livelihoods around the world - including here in the UK and Ireland.

Understanding what overfishing is and why it matters is essential to protecting the health of our oceans. When fish are caught faster than populations can recover, marine ecosystems can become unbalanced, affecting wildlife, coastal communities and future seafood supplies.

Overfishing statistics tell a stark story, and demonstrate the urgent need for action. Enforcing sustainable fishing practices and effective fisheries management is essential to protect ocean health and marine biodiversity for future generations.

Why is overfishing a problem in 2026?

Overfishing is only increasing

The level of overfishing has been increasing in recent decades and the number of overfished stocks is now three times higher than in 1970. The United Nations Food and Agriculture Organization (FAO) monitors over 500 fish stocks around the world. In 2021, it was estimated that over 35% of these fish stocks were overfished globally and 24.2% in the North Atlantic.

Collapse of local economies

For communities reliant on fishing, the impact of stock collapses can be devastating. In Cornwall, for every fisherman at sea, there are 15 more jobs helping to bring seafood to our plate; their work contributes £174 million to the UK economy. In the UK, for example, there has been concern in recent years surrounding overfishing in the North Sea for populations of cod and mackerel, as well as for other species.

Reduced biodiversity

Additionally, the environmental impacts of overfishing include critical losses of ocean biodiversity, including extinctions of entire species. This mass disruption to marine ecosystems is causing untold harm to ocean life and the people and animals that rely on them as an essential food source - and this harm will only increase in the coming years as the effects compound.

What causes overfishing?

There are several factors that drive overfishing, including:

Rising consumption 

The human population reached 8 billion in November 2022 and is expected to reach almost 10 billion by 2050. Consumption of aquatic foods (farmed and wild) is rising twice as fast as the global population.

Climate change

Increases in ocean temperatures change the migratory routes of fish stocks, causing them to move away from traditional fishing grounds. Overfishing occurs when fisheries continue to catch at the same level even though some of their target species have moved to new grounds.

Illegal, Unreported and Unregulated (IUU) fishing

Catching fish without abiding to governmental and international regulations, for example in protected zones, or not reporting part of the catches.

Fishing subsidies

It is estimated that governments have spent billions of dollars on subsidies to support their fishing industries. Sometimes, this might support fishing in overexploited areas where catch revenue will not be enough to cover the expense of fishing. In such cases, subsidies end up encouraging unsustainable fishing practices.

In many regions, these pressures can combine, making overfishing more difficult to address. As fish stocks move in response to climate change and seafood demand continues to grow, international cooperation and science-based management are increasingly important for preventing further stock declines.

What is the alternative to overfishing?

Fishing is sustainable if enough fish are left in our oceans and impacts on marine habitats and ecosystems are minimised. For this to happen, fisheries must follow sustainable fishing practices and be managed effectively.

What are the consequences of overfishing?

The environmental impacts of overfishing are dire, but they’re not the only consequences: declining fish populations can affect food security, economic stability and employment in coastal regions around the world.

Economic fallout

Almost 38 million people are directly employed in the wild capture seafood sector. Figures from the 2020 UN FAO State of the World Fisheries Report show 10% of the world’s population rely, at least partially, on fishing and aquaculture for their livelihoods.

Employment

If fish stocks collapse the impact can be immediate, but recovery can take decades. The collapse of Canada’s Grand Banks cod fishery in 1992 left over 35,000 fishers and plant workers from more than 400 coastal communities without jobs.

Loss of food security

Seafood is also an important source of protein and micronutrients. More than 3 billion people are dependent on the ocean for protein, with fish representing at least 20% of their daily animal protein intake.

The impact of overfishing on biodiversity

Overfishing can affect biodiversity, habitats and ecosystems that make vital contributions to the climate, clean air, water and food.

Seabird death

Biodiversity can also be affected when species captured unintentionally during fishing activities are caught at unsustainable levels. This can include familiar seabirds around the coasts of the UK and Ireland, such as kittiwakes and gannets, which can lose an important food source when small fish become scarce, and may also be harmed through interactions with fishing gear.

Bycatch

More broadly, fisheries can impact birds through bycatch, entanglement and other disruption, which is why reducing these impacts is an important part of sustainable fishing.

Sustainable fisheries work to minimise their negative impact on biodiversity. For example, MSC certified cockle fisheries in Wales and England have worked hard to make sure enough cockles are left to maintain the population at sustainable levels, and for overwintering birds to feed on when they visit our shores.

Seabirds like kittiwakes can often be seen around fishing boats.

What can be done about overfishing?

Addressing overfishing requires action from governments, fisheries, seafood businesses and consumers. Science-based catch limits, effective monitoring and sustainable seafood choices can all play a role in helping fish populations recover and thrive.

Sustainably managed fisheries

Stopping overfishing doesn’t mean stopping fishing altogether. Fisheries that are sustainably managed are better for the environment and more productive in the long-term. 

If all fisheries were sustainably managed there would be an estimated 16 million more tonnes of fish a year, which would yield enough protein for 72 million morepeople. In the UK, 76% of seafood consumers agree that in order to save the ocean, we have to consume seafood from sustainable sources (GlobeScan Consumer Insights, 2025).

As the world grapples with how to feed its growing population, sustainably produced foods from the sea will have an increasingly important role to play. 

Despite the headline statistics on overfishing, there has been steady progress on the availability of sustainable seafood for consumers. 2019 figures in the FAO Blue Transformation report found that 82% of fish landings by volume come from sustainably managed stocks, an increase of nearly 4%. This means consumers are increasingly empowered to make sustainable choices, especially for popular species like tuna and salmon.

What is the MSC doing about overfishing?

The MSC was founded in response to overfishing and our Fisheries Standard can play a major role in its prevention.

Almost a fifth of the globe’s wild marine catch is certified or in assessment to the Standard. It is a globally recognised benchmark for seafood sustainability and reflects the most up-to-date understanding of internationally accepted fisheries science and management.

The MSC Fisheries Standard is a set of requirements that ensure fisheries aiming to be certified as environmentally sustainable only target stocks that are abundant and able to replenish themselves, and that fisheries minimise their impact on the wider marine ecosystem. The Standard also requires that fishing is well-managed, and fishers abide by the relevant local, national and international laws.

Assessments are carried out independently and audits are made every year to make sure requirements are being met.

Recent MSC research found that fish stocks targeted by fisheries certified to the MSC Standard perform better on key sustainability benchmarks than those targeted by non-certified fisheries. These stocks are healthier, more abundant, and much less prone to overfishing.

The MSC Fisheries Standard

The MSC Fisheries Standard is used to assess if a fishery is environmentally sustainable, well-managed and reflects the most up-to-date understanding of fisheries science.

Illegal fishing

Illegal fishing refers to any fishing that breaks local or international laws or regulations, such as fishing without a permit, in closed areas, with prohibited gear, above quotas, or for protected species.

Illegal, unregulated and unreported (IUU) fishing contributes to the problem of overfishing. It can take place without concern for the environment or the strict regulations on fishing quotas. This makes it more difficult for scientists and fisheries managers to accurately assess stock health and set sustainable catch limits.

Estimated to be worth £7.8-18.5 billion annually, IUU fishing threatens the sustainability of fish populations, ecosystems and the livelihoods of those who fish legitimately. 

The MSC program helps to drive out IUU fishing by disqualifying fisheries if they systematically engage in IUU fishing, or where IUU fishing by others is having a negative impact on the sustainability of the overall fishery.

For example, the MSC certified Poole Harbour clam and cockle fishery has overcome challenges related to illegal fishing by introducing a permit bylaw in 2015 for both clams and cockles. This has helped reduce illegal fishing activity by 95%.

The small boats only collect adult Manila clams and cockles, leaving the juvenile shellfish on the seabed, thereby preserving stocks. The fishery also worked to create its own Endangered, Threatened and Protected Risk Management Strategy, which has helped them to better understand and identify relevant species in the area.

Sources

Ambitious subsidy reform by the WTO presents opportunities for ocean health restoration,

https://link.springer.com/article/10.1007/s11625-020-00865-z

Food and Agriculture Organization of the United Nations, https://openknowledge.fao.org/items/3bffafd3-c474-437b-afd4-bb1182feeea6

Illegal, Unreported and Unregulated (IUU) fishing,

https://www.fao.org/iuu-fishing/fight-iuu-fishing/en/

Review of the state of world marine fishery resources – 2025,

https://openknowledge.fao.org/items/8bf1f881-9208-4c59-86e2-9ada635960dd

Wild-caught fish populations targeted by MSC-certified fisheries have higher relative abundance than non-MSC populations,

https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.818772/full

World Population Prospects 2022,

https://www.un.org/development/desa/pd/sites/www.un.org.development.desa.pd/files/wpp2022_summary_of_results.pdf