TV footage shows the team navigating through plates of ice by boat late Tuesday and using flashlights to find the stranded deer, wrap it in a blanket and carry it back to shore.
The animal was one of two roe-deer that were spotted early on Tuesday drifting some 200 metres offshore in northern Poland.
Firefighters managed to chase one back to land during the day but the other deer drifted further out to sea.
Firefighter Waldemar Bogatko says his team faced serious risks saving the second animal on the drifting ice on Tuesday night.
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Last year a Polish boat saved a dog as it also drifted on ice out in the Baltic.
