Illegal, unreported and unregulated fishing
Illegal, unreported and unregulated fishing is a broad term that refers to fishing without the permission of a nation state, 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.
Distinction between types of IUU
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. According to the UN Food and Agriculture Organization, 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.
The drivers behind illegal, unreported and unregulated 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, or to enforce national or international laws. 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.
The Chinese commercial fishing fleet is responsible for more IUU fishing than that of any other nation.
Economic and environmental impacts of IUU fishing
Illegal, Unreported, and Unregulated 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. The most affected areas by this phenomenon are Africa, Asia, and Latin America.The environmental effects of IUU fishing
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' growth 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. 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.
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 artisanal fishers rely: this can create food scarcity, and possible job losses for the local fishermen. Moreover, the coasts are subjected to bycatch of turtles and dolphins. The problem of IUU fishing in Mozambique and Tanzania sometimes derives from artisanal fishermen themselves, who fish during closed seasons in protected areas, and buy illegal catch from other vessels, to process it and sold it in exchange for shrimps, 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.Cargados Carajos Shoals
The main island, Mauritius, is situated 800 km east of Madagascar, has a land area of 2040 km2 and an exclusive economic zone of 2.3 million square kilometres which is impossible 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.
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. As one of the most heavily exploited marine zones in the Atlantic, West Africa's coastal waters represent a frontline in the global struggle against IUU fishing. The region's vast 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 UNCLOS and the FAO Code of Conduct for Responsible Fisheries, which call for the conservation and sustainable use of marine living resources, West Africa remains a hotspot of IUU activity, pointing to the disconnect between legal frameworks and practical enforcement.
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. Furthermore, IUU fishing contributes to unsustainable levels of fishing pressure on critical 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 has cascading ecological effects, reducing prey availability for larger marine predators and altering the structure of marine ecosystems. In many 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.