El Niño 2026 Is Strengthening and Disrupting the Pacific Marine Food Web

As of June 2026, El Niño has officially arrived. This naturally occurring climate pattern is marked by warmer-than-average sea surface temperatures in the equatorial Pacific, along with major changes in atmospheric and ocean circulation. Its effects can extend far beyond the Pacific, influencing everything from desert flooding and delayed monsoons to the formation and movement of tropical cyclones.

The NOAA Climate Prediction Center expects the current El Niño event to strengthen through the end of 2026. Forecasters estimate a 97 percent chance that the event will continue through the early Northern Hemisphere spring of 2027. Even in its early stages, satellites have detected key El Niño indicators, including warmer-than-normal sea surface temperatures and elevated sea surface heights along the equatorial Pacific.

El Niño Is Reducing Phytoplankton in the Equatorial Pacific

One of the earliest ecological effects of El Niño is a disruption to the marine food web. The maps above show chlorophyll-a concentrations, a pigment found in most phytoplankton. The measurements were collected by the Ocean Color Instrument (OCI) aboard NASA’s PACE satellite, short for Plankton, Aerosol, Cloud, ocean Ecosystem.

The June 2025 map, shown on the left, represents relatively neutral conditions. The June 2026 map, shown on the right, captures a strengthening El Niño. The most noticeable change appears in the central Pacific near the equator, north of New Zealand, where chlorophyll-a concentrations are significantly lower than they were the previous year.

According to Matthew Kehrli and Graham Trolley, oceanographers at NASA’s Goddard Space Flight Center Ocean Ecology Laboratory, the decline is consistent with expected El Niño conditions. During an El Niño event, easterly equatorial trade winds weaken. As a result, warm surface water spreads deeper into the ocean, suppressing the upwelling of cool, nutrient-rich water that normally supports phytoplankton growth.

As El Niño continues, scientists expect the reduction in central Pacific chlorophyll-a to become more pronounced. “This may manifest as a greater difference in values across the current region, as a broadening region of reduced surface chlorophyll-a concentration, or both, depending on the behavior of the equatorial trade winds,” Kehrli and Trolley said.

Fewer Phytoplankton Can Affect Fish, Seabirds, and Marine Mammals

Phytoplankton form the foundation of much of the ocean food web. When their abundance declines, fewer food resources are available for zooplankton, fish, seabirds, and marine mammals. These ecological effects can also create serious economic consequences for coastal communities and fishing industries.

Peru’s anchovy fishery has experienced substantial declines in catch during previous El Niño events. Warmer surface waters, weakened upwelling, and reduced phytoplankton productivity make it more difficult for anchovies to find food.

In 2026, Peru’s Ministry of Production repeatedly suspended anchovy fishing in an effort to protect the country’s most important fishery resource. Hungry pelicans have also been observed moving into Peruvian ports and urban areas in search of food.

Phytoplankton May Rebound After El Niño

Although El Niño can severely disrupt marine ecosystems, phytoplankton concentrations may increase after the event ends. This post-El Niño “chlorophyll rebound” can produce higher-than-normal chlorophyll levels across parts of the equatorial Pacific.

Research suggests that the rebound may be fueled by increased iron transported by ocean currents, as well as dust deposited into the ocean from drier regions of Central and South America. The recovery does not necessarily require a subsequent La Niña event.

La Niña often follows El Niño and can also contribute to elevated chlorophyll concentrations. A strong La Niña in 1998 and 1999 triggered a large phytoplankton bloom in the eastern Pacific and led to a significant increase in fish populations.

NASA’s PACE Satellite Provides New El Niño Data

Scientists now have more advanced tools for tracking how El Niño affects ocean ecosystems. NASA’s PACE mission launched in February 2024, making the 2026 event the first complete El Niño for which the satellite can collect global, near-daily hyperspectral observations.

“The scientific community will be able to observe the 2026 El Niño with data across more wavelengths of light than ever before,” Kehrli and Trolley said.

Researchers plan to use PACE data to examine how different phytoplankton communities respond to changing ocean conditions. The satellite’s capabilities also extend beyond marine ecosystems. PACE can measure plant pigment composition on land, as well as clouds and atmospheric aerosols—all of which can be influenced by El Niño.

NASA Earth Observatory images by Michala Garrison, using PACE data from the NASA Ocean Biology Distributed Active Archive Center OB.DAAC and processed by Matthew Kehrli. Story by Lindsey Doermann.

Sources

• The Conversation (2026, June 17). A ‘super’ El Niño has the power to devastate fishing – and leave seals and sea lions starving. Accessed August 6, 2026.
• Lim, H.-G., et al. (2022). Oceanic and atmospheric drivers of post-El-Niño chlorophyll rebound in the equatorial Pacific. Geophysical Research Letters, 49, e2021GL096113.
• Ministry of Production (2026, June 11). PRODUCE reinforces conservation measures and suspends anchovy fishing in the North-Central zone. Accessed August 6, 2026.
• NASA (2016). Ocean Phytoplankton. Accessed August 6, 2026.
• NASA Earth Observatory (2026, June 18). El Niño Is Underway. Accessed August 6, 2026.
• NASA Earth Observatory (2025, September 25). El Niño. Accessed August 6, 2026.
• NASA Earth Observatory (2015, October 29). El Niño Disrupts the Marine Food Web. Accessed August 6, 2026.
• NASA Scientific Visualization Studio (2016, January 29). 2015 El Niño Disrupts Ocean Chlorophyll. Accessed August 6, 2026.
• NWS Climate Prediction Center (2026, July 9). El Niño/Southern Oscillation (ENSO) Diagnostic Discussion. Accessed August 6, 2026.