The lead author of a study on the population of Cape Denison says "it was heart wrenching to see the impact of the fast ice"
Around 150,000 penguins have died after a large iceberg grounded near a colony of Adélie penguins in Antarctica.
A study, published in Antarctic Science, has found that the population at Cape Denison in Commonwealth Bay in December 2013 had reduced to around 10,000 penguins. The compares to a population in excess of 160,000 in 2011.
The sharp decline comes after the iceberg B09B - which has an area of around 100 sq kilometres - grounded in the Bay in 2010.
B09B has effectively cut off the colony's food supplies, forcing the penguins to walk around 60km to find food.
The authors of the study say a separate colony around 8km away from the edge of the iceberg is 'thriving', suggesting the iceberg was 'probably responsible' for the change at Cape Denison.
The writers warn that "the Cape Denison population could be extirpated within 20 years unless B09B relocates or the now perennial fast ice within the bay breaks out.
"Our results have important implications for wider East Antarctic if the current increasing sea ice trend continues," they add.
Lead author Dr Kerry-Jayne Wilson of the West Coast Penguin Trust, New Zealand said, “it was heart wrenching to see the impact of the fast ice on the penguins. The normally noisy and aggressive Adélie penguins were so subdued they hardly acknowledged our intrusion into their realm.
"It was sad to walk amongst thousands of freeze-dried chicks from the previous season and hundreds of abandoned eggs," she added.