Seal populations drastically dwindling as Antartic ice disappears

By Lauren Beavis

Melting sea ice is drastically impacting seal populations, experts warned today.

The new study of Antarctic seals shows that environmental conditions, namely melting sea ice due to increasing temperatures, are leading to a "concerning" and severe decline in their populations in the South Orkney Islands.

Findings have revealed that since around 2015, fur seal numbers have dropped sharply and continue to fall. 

 Michael Dunn, lead author of the study from the British Antarctic Survey (BAS) said: “We’ve seen fur seal populations bounce back in the sub-Antarctic after hunting was banned in the 1960s.

"But this study offers a rare glimpse into the changes now unfolding in one small part of Antarctica.

"For once, we’re not just predicting how wildlife might respond to shrinking sea ice and environmental shifts, we’ve had the rare opportunity to confirm it, using solid, long-term data.

"The emerging picture is deeply concerning.”

The new study looked at three species: Weddell seals, Antarctic fur seals and southern elephant seals. 

It found that Weddell seals, which depend heavily on sea ice to breed and feed, and Antarctic fur seals, which breed on land but are still affected by environmental impacts on the food chain, have declined sharply by 54 per cent and 47 per cent respectively over almost 50 years.

Southern elephant seal numbers shared similar population trends over time, but in this study, they showed no significant overall long-term decline.

The BAS team concluded that changes in all three species are strongly linked to shifts in sea ice, when it forms and melts each year, and how long it lasts.

The new results, which have been published today (Wednesday, June 18) in the journal Global Change Biology, show how seals depend on sea ice for their survival. 

Researchers from the BAS have been monitoring seal numbers in the sub-Antarctic on Signy Island, in the South Orkney Islands, since the 1970s.

Using satellite records of sea ice concentration dating back to 1982, the team tracked annual changes in sea ice timing, extent and duration, then compared them to seal counts carried out every year since 1977.

The set of data spans through a period of long-term warming and a temporary cooling phase from approximately 1998 to 2014.

The BAS team explained how "this natural fluctuation gave the team a 'before and after' scenario", which allowed them to observe how seal populations reacted to changing ice conditions over time.

The results show profound variation in numbers of the three Antarctic species over nearly five decades and challenge earlier assumptions that Antarctic fur seal numbers had stabilised in the South Orkneys.

The team emphasises how this research highlights the vital importance of long-term ecological monitoring. 

The study also sheds light on broader ecosystem risks, with researchers raising concerns about how climate change is disturbing the fragile Antarctic food web – a system all three seal species depend on.