The ice cover is crucial to the birthing season, because the pups are born on the ice and spend a month with their mothers in snow burrows. If there is too little ice for cover, the pups become exposed to predators, they can become separated from their mothers, and even fall into the icy waters before they have developed the necessary protective layer of fat.
This species of seal only reproduces in marine areas which have a layer of ice for an average of 90 days a year.
"The difficulty in the seals' reproduction is one consequence of climate change," says the WWF Finland's chairman of the seal unit, Antti Halkka.
"Climate models predict that the ice on the Baltic Sea will decrease by 50 to 80 percent by the end of the century, unless the rise in global temperatures is stopped. We have to radically reduce CO2 emissions or the seal may disappear from the Baltic."
There are four main Baltic ringed seal populations in Finland. Last year, which was the driest in several centuries, three of the four populations suffered tremendous losses, with more than half of their newborn pups dying.
The Baltic ringed seal, listed as a "threatened species", should not be confused with the highly endangered Saimaa ringed seal.