Warming waters draw summer ‘feeding frenzies’ by whales off Greenland

The effects of global warming depend on species: The losers are legion, but a lucky few are winners. Now, researchers have shown that baleen whales are taking advantage of a newly opened-up fish bonanza in the Greenland Sea, east of Greenland and reaching to the Arctic Circle and beyond.

“Here we show that rising ocean temperatures and declining sea ice cover have facilitated the widespread occurrence of baleen whales along the East Greenland coast, as far north as 70°N,” said Professor Mads Peter Heide-Jørgensen of the Greenland Institute of Natural Resources. “This has led to regular mixed ‘feeding frenzies’ of fin whales, humpback whales and common minke whales—species that historically were only rarely observed in coastal East Greenland.”

Heide-Jørgensen and colleagues in Greenland, Denmark and Iceland documented this latest spectacle of the natural world in a study in Frontiers in Marine Science. They emphasized that it could spell major changes up and down the local food chain.

The Arctic and North Atlantic—apart from a puzzling ‘cold blob’ south of Greenland—are among the fastest-warming regions on Earth. For example, sea surface temperatures east of Greenland have risen by approximately 2°C since the 1990s. The ice edge in summer retracted far to the north after the mid-2000s, dramatically reducing the extent of pack ice along Greenland’s east coast.

First systematic surveys

The authors conducted the first systematic aircraft survey of baleen whales up to 50 km (31 miles) off the East Greenland coast in August 2015 and 2024. They added further airborne observations in the summer of 2022, testimony from Inuit hunters between 2023 and 2025, and records from ships taking part in North Atlantic Sighting Surveys since 1987. They also analyzed tracks from 15 satellite-tagged baleen whales collected at intervals between 2019 and 2025. They then built a mathematical model to find patterns within this sea of data, using historical measurements of key factors like sea surface temperature, salinity and ice pack concentration to explain the variation.

Together, the results provide a unique record of changes in the abundance of baleen whales in the Greenland Sea over the past three decades.

The picture was uniform: Between 1987 and 2024, there was a marked change in the occurrence of baleen whales along the East Greenland coast north of 60°N and west of 29°W. For example, ship-based surveys didn’t observe any humpback whales until 2006, while seven sightings were recorded in 2007, 26 by 2015 and more than 150 by 2024. Similarly, sightings of minke whales from the survey vessels were few until 1995, but 10–20 were encountered each year after 2001.

Ship-based sightings of fin whales likewise increased sharply from 1987 to the present day. In August 2025, a ship crew reported encountering exceptionally large aggregations of up to 50 baleen whales simultaneously along the east coast around 69°N, north of the Arctic Circle. Likewise, the systematic airborne surveys documented an almost continuous distribution of all three species at the same time between 60°N and 70°N in 2015 and 2024.

A fish called capelin

Heide-Jørgensen and colleagues estimate that altogether, no fewer than 4,000 humpback whales, 6,000 fin whales and 6,000 minke whales visited the Greenland Sea in the summer of 2024.

“There is little doubt that the three baleen whale species summering in East Greenland coastal waters do so primarily to feed,” the authors observed.

But what might bring them to the region in these staggering numbers? The authors found that the trio visits the region mainly to hunt for capelin—a cold-loving fish known to be one of their most important prey farther south. Capelin have recently been shown to have shifted their feeding grounds since the mid-2000s from the relatively warmer waters north of Iceland toward the Greenland Sea. The conclusion must be that baleen whales have caught up with this shift and moved in for the kill.

Reassuringly, there have never been any commercial capelin fisheries in this region, so competition with humans doesn’t seem likely for now.

“East Greenland is undergoing a major ecological regime shift. Ice-associated species such as narwhals are increasingly sharing their habitat with, or being displaced by, temperate baleen whales that generally avoid ice-covered waters,” Heide-Jørgensen concluded. “This marked change in species composition demonstrates how climate-driven changes are reorganizing the East Greenland marine ecosystem, potentially with long-lasting consequences.”

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