By Koroi Tadulala
Months have passed since El Niño was declared across the Pacific, and its effects are being felt far and wide.
At the same time, the United Nations Environment Programme’s Limiting Overshoot report highlights the increasing likelihood of temporarily exceeding 1.5°C of global warming and warns that higher peak temperatures increase the risk of irreversible impacts.
Current El Niño conditions provide a clear example of how natural climate variability is interacting with an already warming ocean, resulting in unusually high ocean temperatures across parts of the Pacific.
Most Pacific communities are experiencing drought, damaged crops, and shrinking water supplies with reports from several countries that points to drought and frost damage in parts of Papua New Guinea, water scarcity in parts of Vanuatu, Fiji, and Tonga among other countries and agricultural losses that are placing increasing pressure on livelihoods and food security.
While these impacts are visible above ground, there is a silent battle happening beneath our ocean’s surface. Throughout the vast stretches of our Pacific Ocean, unusually warm ocean temperatures in the central and eastern Pacific and cooling in the western Pacific are altering marine conditions in ways that are less visible but equally significant.
International concern over the warming Pacific has also been raised at the highest levels.
“El Niño is being supersised before our eyes. The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up,” said United Nations Secretary-General António Guterres.
Ocean temperatures have remained well above normal for several months, with coral bleaching alerts now active across much of the region. Scientists warn that sustained ocean warming is placing coral reef ecosystems under increasing stress.
The figure shows the unusual weather conditions manifesting across the Pacific, which deviate from historical observations (anomaly) and show the strength of the current El Niño.
Pacific Community’s (SPC) Fisheries, Aquaculture and Marine Ecosystems (FAME) Division scientist Dr Victor Odongo explains:
“Tunas are highly sensitive to changes in their environment and each species is adapted to specific temperature ranges, oxygen levels, and of course, prey abundance. When El Niño pushes species’ ideal conditions across the ocean, the tuna follow by moving to different latitudes, longitudes, and depths,” said Dr Odongo.
As warm ocean temperatures shift from the western Pacific towards central and eastern Pacific, tuna stocks move eastwards as well, following favourable environmental conditions for their survival. This large-scale migration is reshaping fishing activity across the vast Blue Pacific.
The movement of tuna stock also drives the movement of fishing fleets, as vessels follow the fish into new grounds of the central and eastern Pacific. This results in a decline in commercial purse-seine catches, (a fishing method that catches large groups of tuna by encircling them with a large net) in western Pacific countries such as Papua New Guinea, the Solomon Islands, and the Federated States of Micronesia.
Consequently, these countries earn less money from fishing licences and commercial fishing. At the same time, local fishers need to travel farther to find fish, spending more on fuel and facing increased risks at sea.
On the other hand, Kiribati, an atoll nation spread across a vast area of the central Pacific, has enjoyed increasing fishing activity for the past months. Its fishing industry generates 70 percent of the country’s revenue – the highest proportion by any nation.
For a country comprised of small, widely dispersed atolls, the tuna industry represents a vital economic lifeline.
“Our monthly Ocean Outlook provides insights that help generate economic activity at the national level. Through the Pacific Ocean Portal supported by the Climate and Oceans Support Program in the Pacific (COSPPac), we’re able to identify hotspots for fishing activities within our exclusive economic zone which attracts international fishing vessels, and this is where most of our government revenue comes from,”said Ueneta Toorua, Director of the Kiribati Meteorological Service.
These country-specific National Monthly Ocean Outlooks are developed through a series of capacity-building workshops led by SPC and co-designed with national ocean stakeholders, coordinated through the National Meteorological and Hydrological Services (NMHSs). This collaborative process combines scientific expertise, local knowledge, and user needs to produce tailored ocean information that supports decision-making across sectors.
According to the latest forecasts presented through the COSPPac Monthly Climate and Ocean Bulletin, increased tuna fishing activity is expected to continue across central and eastern Pacific, including Nauru, Kiribati, Tokelau and Tuvalu, throughout the latter part of 2026.
However, the benefits are not without challenges. Kiribati has also experienced months of heavy rainfall linked to El Niño causing flooding across parts of the country, inundating major roads and low-lying coastal communities.
While tuna-rich waters create economic opportunities in some areas, the environmental consequences of warmer ocean temperatures are becoming increasingly evident. Rising ocean temperatures increase the likelihood of marine heatwaves and prolonged coral bleaching events, threatening important coastal habitats.
“These episodic warming events can trigger a domino effect: rising fish mortality, crippled coastal tourism, and severe damage to local aquaculture infrastructures and cultured organisms increase the risks of economic losses,” said Dr Victor Odongo, Pacific Community.
The effects extend well beyond coral reefs. As habitats deteriorate, populations of reef fish can decline, reducing food availability for local communities that depend on coastal fisheries.
SPC’s Ocean Science Officer, Dr Moleni Tu’uholoaki stresses that current monitoring shows that El Niño conditions are expected to persist over the coming months, with forecasts indicating the event could continue through February 2027.
For fisheries, this means the eastward redistribution of tuna stocks is likely to continue, bringing increased fishing effort and transhipment activity across the central Pacific, particularly around Kiribati and neighbouring atoll nations.
At the same time, elevated ocean temperatures are expected to maintain pressure on coral reefs and marine ecosystems across much of the Blue Pacific.
Dr Odongo points to successful frameworks like the Parties to the Nauru Agreement, which cooperatively manages the regional purse-seine fishery, as a blueprint for navigating El Niño’s uneven impacts across the Pacific.
“Ultimately, safeguarding the Pacific will require helping local communities diversify their livelihoods, ensuring that the periodic ocean changes don’t hang their survival in the balance.”
As countries grapple with varying impacts of El Nino, the coming months will present a complex picture for our Blue Pacific. While some nations may benefit from increased fisheries revenue, others will continue to face risks of prolonged drought, water shortages, ecosystem degradation, and mounting climate-related risks.
While El Niño evolves, so does the continued monitoring of ocean conditions through tools such as the Pacific Ocean Portal, a key tool used by National Meteorological and Hydrological Services to monitor sea-surface temperatures, and access coral bleaching and marine heatwave outlook, chlorophyll concentration information amongst a range of other products that help inform national preparedness and response.
