Greenland's glaciers play a crucial role in the Arctic ecosystem, and their rapid melting is leading to significant changes. Research has shown that this process directly affects the feeding habits of ringed seals, forcing them to switch to less calorie-rich prey.

Impact of Glacier Melting

The Greenland ice sheet is melting at an increasing rate. Among the main consequences of this phenomenon are rising global sea levels, disruption of food chains, and changes in the habitats of marine mammals. The ringed seal, the most numerous seal in the Arctic and a key food source for polar bears as well as a traditional resource for Greenland's indigenous peoples, is especially vulnerable to these changes.

The Role of Glacier Fronts

Since the 19th century, scientists have suggested that areas where glacial waters enter the sea attract marine animals. Glacial runoff causes upwelling of deep waters, enriching surface layers with nutrients and stimulating phytoplankton growth. This, in turn, attracts zooplankton and fish, particularly capelin. However, observing seal behavior near glaciers is challenging, and remote methods do not always allow for precise determination of feeding behavior.

Studying the Ringed Seal's Diet

Understanding how climate change affects the ringed seal's food base is vital for assessing the species' future. Special attention is given to identifying the link between seal presence and active feeding in glacier-sea contact zones.

During fieldwork in 2022 and 2023, local hunters provided researchers with the stomachs of harvested seals, along with precise coordinates of where they were caught. The rapid digestion in this species allowed scientists to view stomach contents as a snapshot of the last meal, tied to a specific location. In total, 42 samples were collected and analyzed. At the same time, hydroacoustic surveys of the fjord were conducted to objectively assess the distribution of potential prey.

Main Findings

Analysis showed that seals caught near glacier fronts had full stomachs, while those caught farther away were more often hungry. The mass of stomach contents decreased with distance from the glacier. The diet of seals living near glaciers was dominated by capelin—a fish that forms dense schools in these waters. Further from the glaciers, the diet became more varied, indicating a shift in feeding strategy: when large, energy-rich fish are available, seals prefer to hunt them rather than spend time on small crustaceans.

Consequences for the Seal Population

The data indicate that glacier fronts serve as vital summer feeding grounds for ringed seals. As glacier melting accelerates, the productivity of these zones drops sharply, and these rich feeding areas disappear. Deprived of access to capelin, seals are forced to switch to less nutritious food or search for new hunting grounds, which affects their physical condition and survival rates.