Illegal, unreported and unregulated fishing (IUU) is a broad term that refers to fishing without the permission of a government, or in contravention of its laws and regulations; unreported or misreported fishing; and fishing that is conducted in an area with no applicable conservation or management measures. IUU is an issue around the world. The fishing industry observers believe IUU occurs in most fisheries, and accounts for up to 30% of total catches in some important fisheries.World Wildlife Fund. "Fishing problems: Illegal fishing"
Illegal fishing takes place when vessels or harvesters operate in violation of the laws of a fishery. This can apply to fisheries that are under the jurisdiction of a coastal state or to high seas fisheries regulated by regional fisheries management organisations (RFMO). According to the UN Food and Agriculture Organization (FAO), Fisheries and Aquaculture Department, illegal fishing has caused losses estimated at US$23 billion per year.
Unreported fishing is fishing that has been unreported or misreported to the relevant national authority or RFMO, in contravention of applicable laws and regulations.
Unregulated fishing generally refers to fishing by vessels without nationality, vessels flying the flag of a country not party to the RFMO governing that fishing area or species on the high seas, or harvesting in unregulated areas.
IUU fishing poses a global challenge and has significant economic and environmental repercussions. The impact of IUU fishing includes economic losses, job losses, scarcity, price distortion, food insecurity and unfair competition, together with the depletion of fish populations and damages to the marine habitat.FAO Regional Conferenze for Asia and the Pacific (2020).Report on work in the Fight against Illegal, Unreported and Unregulated Fishing in Asia and the Pacific. Food and Agriculture Organization of the United Nations. The most affected areas by this phenomenon are Africa, Asia, and Latin America.Centre For Latin America and Latino Studies (2022). Adverse Consequences of IUU Fishing. American University. The Chinese commercial fishing fleet is responsible for more IUU fishing than that of any other nation.
The drivers behind illegal, unreported and unregulated (IUU) fishing are similar to those behind many other types of international environmental crime: pirate fishers have a strong economic incentive – many species of fish, particularly those that have been over-exploited and are thus in short supply, are of high financial value. Such IUU activity may then show a high chance of success – i.e. a high rate of return – from the failure of governments to regulate adequately (e.g. inadequate coverage of international agreements), or to enforce national or international laws (e.g. because of lack of capacity, or poor levels of governance). A particular driver behind IUU fishing is the failure of a number of flag states to exercise effective regulation over ships on their registers – which in turn creates an incentive for ships to register under these flags of convenience.
Environmental impacts
The environmental effects of IUU fishing include biodiversity loss, and damages to the marine flora and ecosystem, and are generally caused by illegal fishing methods, overfishing and bycatch.
Illegal fishing methods usually damage the seabed and the marine flora: fishing gears, chemicals, and explosions, can affect organisms' growthJennings, S., & Kaiser, M. J. (n.d.). The Effects of Fishing on Marine Ecosystems. and cause sediment transport, which blocks or reduces light, endangering the growth and settlement of oysters and scallop. Fishing gears and fishing methods in prohibited areas often damage the habitat, leading to environmental damage and fish detriment.International Maritime Organization (2024).Illegal, Unreported and Unregulated (IUU) Fishing.https://www.imo.org/en/OurWork/IIIS/Pages/IUU-FISHING.aspx Examples include the use of bottom trawling, which destroys sponges that take decades to regrow, and the use of fishing gears like beach seines and dynamite fishing, which highly damage the reef ecosystems and can kill up to 80% of the coral reef in the target areas.Interafrican Bureau For Animal Resources (n.d.).Economic, Social and Environmental Impact of Illegal, Unreported and Unregulated Fishing in Africa. African Union.Coral Reef Alliance (2005). Coral Reefs & Exploitive Fishing.https://coral.org/wp-content/uploads/2014/02/exploitivefishing.pdf
The impact on fish stock is an effect of overfishing and overharvesting, which can damage the ecosystem biodiversity and can create an imbalance in the food chain, thus affecting predators, forage species, and marine mammals. In addition, the catch of high market valued species, such as tuna and sharks, contribute to the depletion of fish stocks, causing both environmental effects, and food scarcity. Bycatch further exacerbates fish depletion and ecosystem damage, because the catch is often left in the ocean, contributing to ocean pollution, harming marine life, and impacting the honest fishermen' economy, who cannot sell that fish if they catch it.
Africa
In Eastern Africa, the coasts in Tanzania suffer the use of trawlers from foreign vessels, which impact the ecosystem, fish and crustaceans, upon which fishers rely: this can create food scarcity, and possible job losses for the local fishermen. The coasts are subjected to bycatch of turtles and dolphins. The problem of IUU fishing in Mozambique and Tanzania sometimes derives from fishermen themselves, who fish during closed seasons in protected areas, and buy illegal catch from other vessels, to process it and sell it in exchange for shrimp, which are overfished. The country also suffers the use of dynamite fishing, which destroys coral reefs, sea-grass beds, mangroves, and salt marshes, thus compromising the habitat. In Kenya, the overexploitation of some kinds of fish has led to a disproportionate increase in their forage, such as the sea urchin, which feeds on the reef, thus reducing the coral cover dramatically.
Mauritius, situated 800 km east of Madagascar, has a land area of 2040 km2 and an exclusive economic zone (EEZ) of 2.3 million square kilometres, which is difficult to patrol and control, given its resources. This leads to massive Illegal, unreported and unregulated fishing by foreign fishing fleets including the Taiwanese fleet, which has the biggest fleet based in Port Louis and is documented as flouting the law, including human rights, worldwide multiple times on record. Mauritian fishing cooperatives also allegedly engage in illegal, unreported and unregulated fishing and are sometimes apprehended but their movements are impossible to track. The country includes the Cargados Carajos Shoals.
West Africa has been consistently identified as the global epicentre of IUU fishing, with estimates indicating that up to 37% of fish caught in the region are unreported or illegal. Evidence of foreign industrial fleets exploit enforcement gaps, weak governance, and limited maritime capacity to extract significant marine resources, often undermining the livelihoods of artisanal fishing communities. While West Africa has received growing scholarly and policy attention, the South Atlantic remains relatively underexplored in academic literature despite facing similar vulnerabilities. The region's large Exclusive Economic Zones, rich biodiversity, and relatively limited enforcement infrastructure have made it particularly susceptible to incursions by foreign industrial fleets. Despite the existence of global governance instruments such as the United Nations Convention on the Law of the Sea (UNCLOS) and the FAO Code of Conduct for Responsible Fisheries, which call for the conservation and sustainable use of marine living resources, West Africa has substantial IUU activity.
In addition to its socioeconomic impacts, IUU fishing in West Africa has severe environmental consequences. Illegal vessels frequently use destructive fishing techniques, such as bottom trawling and the use of fine-mesh or prohibited gear, which lead to seabed degradation, habitat destruction, and the bycatch of juvenile and non-target species. These practices contribute to the collapse of fish stocks, disrupt marine food webs, and threaten the long-term sustainability of marine biodiversity in the region. The lack of adequate monitoring means that endangered species, such as sharks, sea turtles, and marine mammals, are often caught unintentionally and discarded at sea, contributing to biodiversity loss. IUU fishing contributes to unsustainable levels of fishing pressure on species such as sardinella, horse mackerel, and hake, many of which are essential for both ecological balance and food security. The overfishing of these species reduces prey availability for larger marine predators and alters the structure of marine ecosystems. In parts of the South Atlantic, particularly in Angola and Namibia, IUU fishing has also been associated with increased levels of pollution and discarded fishing gear, which exacerbate marine plastic waste and further damage fragile ocean habitats.
Climate change is compounding these effects. Warmer sea temperatures and shifting fish distributions make stocks more vulnerable to IUU exploitation, particularly in upwelling zones such as the Canary and Benguela Currents. In such regions, depleted fish stocks recover more slowly due to changes in ocean productivity and nutrient flows, magnifying the long-term ecological toll of illegal fishing.
Asia-Pacific Region
Overfishing and bycatching in the Asia-Pacific region are destroying coral reefs and are depleting endangering the species by non-respecting the safe biological quota for fish replenishment.Frank, M.;Lack, M.(2008).Assessment of Impacts of Illegal, Unreported and Unregulated (IUU) Fishing in the Asia-Pacific.Asia-Pacific Economic Cooperation Fisheries Working Group. Moreover, the destructive fishing practices in the region involve the use of cyanide to poison reef fish: as a consequence, 56% of coral reefs in Southeast Asia are at risk, especially in the Paracel Islands, Indonesia, Taiwan, Philippines, and Malaysia. Dynamite fishing has destroyed 50% of the coral reef in Southeast Asia, endangering the food security of the population who relies on fish as primary food and income.National Intelligence Council(2016).Global Implications of Illegal, Unreported, and Unregulated (IUU) Fishing. National Intelligence Council and US Intelligence Community.
Oceania In Australia, IUU fishing is affecting biodiversity, and is leading to a decrease of legal fish traps in favor of the illegal ones.Almubarak, S. (2020). Illegal fishing and its impacts on marine life. International Journal of Life Sciences Research. www.researchpublish.com Illegal fishing is endangering the species of sea cucumber and oysters, leading to fish depletion, and damages to the ecosystem. Bycatch and illegal fishing are the main causes of turtle decrease in stock. The most endangered species by IUU fishing are scale fish, rock lobster, sharks and billfish. Bycatch in New Zealand has endangered the survival of the Maui dolphins., and dynamite fishing in the continent is killing corals that takes centuries to rebuild.
Europe