Waste from fish farms such as uneaten food and dead fish can accumulate and destroy parts of the sea.

ECONOMIST: Fish farming

What is more, the extent of sea ice cover influences the abundance of krill and the fish species that eat them - both food sources for the penguins.

BBC: Emperor penguins face extinction

Giery said the hospital's diagnosis at the time of death was that his illness was caused by food poisoning from ciguatera, a toxin sometimes found in large saltwater fish including grouper, red snapper and sea bass.

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