Manmade snowbanks give ringed seals a chance

fieldnotes snowbanks summer2018

SAFETY IN NUMBERS The population of Saimaa ringed seals is estimated at 380 individuals. WWF aims to keep that number growing each year.


Each winter the ringed seals of Finland’s Lake Saimaa give birth inside snowbanks atop the frozen lake. But as climate change has warmed winters, snow accumulations have decreased. In low-snow years, the seals give birth on bare ice, exposing pups to predators and the cold; in the worst years, up to half the pups die. Now volunteers organized by WWF-Finland and Parks & Wildlife Finland are stepping up to save these extremely endangered seals. This winter, volunteers built nearly 290 snowbanks—10 more than last year. This season’s pups haven’t yet been counted, but last year 73 out of 82 pups were born in the manmade snowbanks and hopes are high the trend will continue.

Building snow banks

  1. As nesting season nears, volunteers use a map created with data from past inventories to scout for spots where the seals have nested before.
  2. If the natural snowbanks at preferred nesting sites are already large enough, volunteers move on to build on secondary sites.
  3. The seals dig their lairs from underneath, so volunteers make a hole in the ice under each snowbank to check whether there is enough water for the seals to swim in. The snowbanks need to be about 3 feet high, 10 feet wide, and 26 feet long. The bigger they are, the longer they last, sheltering the pups into the spring.

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