Melting sea ice brings whale 'feeding frenzies' to East Greenland, study finds

The decline and near-disappearance of summer sea ice in East Greenland have opened coastal feeding grounds to thousands of large whales, contributing to a rapid reorganization of the region's marine ecosystem, according to a new study.

The research, published Thursday in the journal Frontiers in Marine Science, found that humpback, fin and minke whales now regularly feed along the East Greenland coast as far north as 70 degrees latitude and probably beyond.

Persistent coastal pack ice historically restricted these boreal whale species' access to the area. However, researchers found that sea ice declined sharply after about 2000, while summer and autumn sea surface temperatures increased by approximately 1 degree Celsius from levels recorded before the late 1990s.

The changing conditions have allowed whales to enter nearshore feeding areas that were previously largely inaccessible, while temperature-sensitive fish such as capelin have increasingly shifted from waters around Iceland toward the East Greenland shelf.

Systematic ship surveys did not record humpback whales in the region before 2007, when seven were observed. That number increased to 26 in 2015 and more than 150 in 2024.

Aerial surveys conducted in 2015 and 2024 also found an almost continuous distribution of humpback, fin and minke whales along the coast between 60 and 70 degrees north.

The 2024 survey estimated that the area contained about 3,900 humpback whales, 5,200 fin whales and 6,400 minke whales. The estimated minke whale population in particular, had more than doubled from approximately 2,800 in 2015.

Researchers combined the aerial and ship surveys with satellite tracking of nine humpback whales and six fin whales, as well as field observations and reports from local hunters.

Satellite data showed that some whales remained in East Greenland's coastal waters into October. The study estimated that the animals spend at least four months in the region each year, primarily to feed.

- Whales could consume more than 1 million tons of prey annually

Evidence from harvested minke whales and observations of feeding groups suggests that capelin is one of the whales' main food sources, alongside krill and potentially other fish and squid species.

The researchers conservatively estimated that the three whale species consume more than 800,000 tons of prey during their seasonal stay. When increased summer feeding rates are considered, consumption could exceed 1 million tons.

The authors cautioned that the figure is an approximate estimate because of uncertainty over whale numbers, feeding rates and the animals' exact length of stay.

They said the influx was likely caused by a combination of reduced sea ice, warming waters, changes in prey distribution and the long-term recovery of North Atlantic whale populations following the end of large-scale commercial whaling.

Some animals may also have moved from West Greenland, where the abundance of fin and minke whales has declined.

The study described the change as the rapid "borealization" of East Greenland's marine environment, in which species associated with warmer waters expand northward while Arctic species retreat.

Researchers said the arrival of thousands of whales introduces a major new source of predation on capelin, a key forage fish that supports other predators and several commercially important fish populations.

The findings suggest that melting sea ice is not merely changing where whales can travel but also reorganizing food webs, predator-prey relationships and potential competition with fisheries across East Greenland.