The Saimaa ringed seal, a subspecies of ringed seal, is among the most endangered seals in the world, having a current total population of only about 310 individuals in the Saimaa area of Finland. The population is descended from ringed seals that were separated from the rest of their species after the last ice age. This seal, along with the Ladoga Seal and the Baikal Seal, is one of the few living freshwater seals in the world and Finland is working hard to preserve its tiny population.
Ringed seals in Saimaa will soon be looking for dens because in just a few months, new pups will be born.
“This kind of variable weather is good for the seals because it adds layers to the snow that make the snow dens more sturdy,” says Ismo Marttinen, a volunteer with World Wildlife Fund Finland.
It is estimated that some 60 ringed seal pups were born in the eastern region of Saimaa last spring and the same number is expected this year. Last year, almost all of the pups that were born were birthed in man-made dens. Seal pups born on the open sea are at much more risk of being eaten by a fox, for example.
Saimaa ringed seals tolerate each other’s company well, but do not live in groups like other seals with larger populations.
“In the spring, they can get into fights over good resting rocks,” says Marttinen.
Tunnels go on and on
Saimaa ringed seals use the sharp claws on their flippers to dig a den, which is normally two metres long and complete in just 24 hours. The dens are typically located just under the surface of the snow, so the seals can enter the water easily and swim. During the winter, however, many seals expand their dens with tunnels up to tens of meters long. Even the pups sometimes help to build the tunnels.
The seal's pups are usually born in late February-early March, but the females can sometimes start to build dens months in advance. The pups go for their first swim in the water already when they are just a few days old. The seals are forced to abandon their dens already in late April most years, as the ice begins to thaw.
Saimaa seals can stay below water for about twenty minutes at a time, after which they must swim to the surface for air. During the winter months, the seals maintain dozens of breathing holes in the ice near their den.
The Saimaa ringed seal has no real enemies in nature, but humans pose the greatest risk to the survival of this fragile species. Several pups are lost each year in fishing nets. The Saimaa seal lives for 25 to 30 years and females can give birth to some 20 pups in their lifetime.
