A survey of this year's Saimaa ringed seal breeding population has found that 32 pups were born to this highly endangered freshwater species this winter, but that nine have died.
The number of new pups observed this year is only about a third as many as born annually in recent years. However, researchers say that it is possible that they missed a few during their count.
"The survey was carried out under difficult conditions, and not all the pups were found. Finding pups born on the open ice is a matter of chance. The number of females who had pups, however, was the same as last year," says conservation biologist Jouni Koskela from state-owned land and water administrator Metsähallitus.
According to Koskela, the actual number of pups born this spring may remain a mystery. Later this spring divers will look for traces of the downy fur shed by pups near dens in order to get a better idea of which were occupied by newborns.
Pups on open ice are easy prey
The Saimaa Lake district which is home to these seals saw unusually low levels of snowfall this winter. In breeding areas, volunteers shovelled what snow there was into piles along the lake shore in which females could dig the dens in which they birth and raise their newborn pups. However, in many spots, the snow melted before the seals could settle in.
Half of the pups counted in the survey were either in dens in these man-made snowdrifts, or close by.
On the open ice, seal pups are easy prey for predators, for example foxes.
"Almost all of the Saimaa seal pups lacked the protection that a den provides from predators and against the cold. Of the nine pups that died, six were killed by predators. In three of the cases, either surveillance cameras for tracks in the snow showed that they were killed by foxes," Koskela explains.
The Saimaa ringed seal population is around 400.
"After a year like this one, we can say that the population is not growing, more likely it's in decline," Koskela points out.