El Niño 2026: the climate signal reshaping oceans, fisheries and aquaculture
From the Pacific Ocean to the Mediterranean and African coasts, a potential “Super El Niño” could intensify marine heatwaves, harmful algal blooms and ecosystem stress. Fisheries, aquaculture and coastal communities may soon face cascading environmental and economic impacts on a global scale.
The return of El Niño is once again drawing the attention of climate scientists, oceanographers and fisheries experts worldwide. According to forecasts from AccuWeather, the phenomenon developing in the Pacific Ocean during 2026 could evolve into a rare “Super El Niño”, potentially becoming one of the strongest recorded in modern history.
El Niño is a natural climate oscillation linked to the warming of surface waters in the eastern equatorial Pacific Ocean. When sea surface temperatures rise at least 0.5°C above long-term averages, El Niño conditions are declared. In extreme cases, where warming exceeds 2°C, the event is classified as a “Super El Niño”, a phenomenon observed only a handful of times since the mid-20th century.
Although originating in the Pacific, El Niño influences atmospheric circulation patterns across the entire planet. Its effects extend far beyond South America, modifying rainfall regimes, storm tracks, monsoon intensity, drought occurrence and ocean temperatures on a global scale.
Impacts along the Pacific coast
The Pacific coastline is usually the first region to experience direct consequences. Peru and Ecuador often face warmer coastal waters, reduced nutrient upwelling and severe disruptions to marine productivity. The weakening of nutrient-rich cold currents dramatically affects anchovy fisheries, one of the world’s largest fishery resources, with cascading impacts on food supply chains and fishmeal industries.
Warmer waters also create ideal conditions for harmful algal blooms (HABs), commonly referred to as “red tides.” These blooms can release toxins dangerous for marine organisms, aquaculture systems and human health. Episodes associated with previous strong El Niño events caused mass mortalities of fish, shellfish and marine invertebrates, generating significant economic losses for coastal communities dependent on fisheries and aquaculture.
Marine heatwaves and global ocean stress
One of the most concerning consequences associated with strong El Niño events is the amplification of marine heatwaves. These prolonged periods of unusually high ocean temperatures are becoming increasingly frequent under climate change and can destabilize marine ecosystems worldwide.
Elevated temperatures reduce dissolved oxygen levels in seawater, increase metabolic stress in marine organisms and alter species distribution patterns. Pelagic species such as tuna, sardines and mackerel may shift migration routes toward cooler waters, while benthic communities, including mollusks, sea urchins and crustaceans, often suffer severe stress due to reduced oxygen availability and habitat degradation.
Coral bleaching events also intensify during strong El Niño phases, particularly in tropical and subtropical regions. The ecological damage extends across food webs, affecting biodiversity, fisheries productivity and ecosystem resilience.
From the Pacific to the Mediterranean and Africa
Although geographically distant from the Pacific, the Mediterranean basin and African coastal regions can also experience indirect consequences linked to El Niño-driven atmospheric anomalies.
Scientific studies have shown that El Niño events can influence rainfall variability in North and East Africa, altering drought and flooding patterns. Eastern African countries may face episodes of extreme rainfall and flooding, while southern Africa often experiences drought conditions affecting agriculture, freshwater availability and coastal ecosystems.
The Mediterranean Sea, already considered a climate change hotspot, may experience intensified marine heatwaves during strong global warming anomalies associated with El Niño. In recent years, Mediterranean waters have repeatedly recorded exceptional temperature peaks, creating favorable conditions for jellyfish proliferation, invasive species expansion and harmful algal blooms.
Aquaculture systems are particularly vulnerable. Mussel farming, seabass and seabream production, oyster cultivation and lagoon ecosystems can all be heavily affected by elevated water temperatures and eutrophication processes. Episodes of mussel mortality linked to oxygen depletion and toxic blooms have already been documented in several Mediterranean farming areas during anomalously warm summers.
Aquaculture under pressure
The aquaculture sector faces growing exposure to climate-driven marine instability. Warmer waters accelerate pathogen proliferation, increase disease outbreaks and reduce oxygen availability inside farming systems.
Harmful algal blooms represent one of the most severe threats. Certain algal species can produce toxins that accumulate in shellfish, forcing harvesting bans and creating major economic losses. Fish cages exposed to red tides may experience sudden mass mortalities caused by gill damage and hypoxic conditions.
For benthic species, prolonged warming and sediment alteration can reduce reproductive success and habitat quality. For pelagic fisheries, changing migration patterns complicate stock management and increase uncertainty for fishing communities.
These impacts are not isolated environmental phenomena. They directly affect food security, employment, export markets and the socio-economic stability of coastal territories dependent on marine resources.
A warning for the blue economy
The possible arrival of a Super El Niño highlights the increasing vulnerability of marine ecosystems in a warming world. Fisheries, aquaculture operators and coastal authorities are now facing the challenge of integrating climate resilience into management strategies.
Early warning systems, continuous ocean monitoring, adaptive fisheries governance and climate-smart aquaculture practices will become increasingly essential to reduce future risks. The interaction between climate variability and human pressure on marine ecosystems is accelerating, making scientific cooperation and sustainable ocean management more urgent than ever.
For the blue economy sector, El Niño is not only a climate phenomenon. It is a global stress test for the future resilience of oceans, seafood production systems and coastal communities.
El Niño 2026: the climate signal reshaping oceans, fisheries and aquaculture
