Itämereen kadonneet valaat ja mursut kohtaavat surullisen loppunsa

Kun tapaat mursun Virossa, then stay away
Kun tapaat mursun Virossa, then stay away tankin puolustus: JOHAN NILSSON/Scanpix Baltics
  • The animals enter the Baltic Sea through the Danish Straits.
  • It is difficult to exit the Baltic Sea.
  • Our waters are not suited for the accidental visitors.

Two men who went to sea from Kokkola in Western Finland immediately before Midsummer Day believed to have sighted a whale. A walrus was found on a beach in Latvia early this week. Does this mean that we can meet new species in the Baltic Sea from now on?

The Finnish men told the Ilta-Sanomat newspaper that the back of the sighted animal had been uneven and wrinkled like that of a crocodile and decided that its appearance resembled a humpback whale. According to a Finnish marine biologist, it could be possible but an exceptional occurrence because humpback whales reach Finland’s shores only rarely.

But how usual is it that whales and walruses end up in the Baltic Sea? Estonian Professor of marine biology Georg Martin said that it is not usual but neither is it extremely rare. «It happens now and then that ocean creatures enter the Baltic.»

Martin explained that the only way for the animals to enter the Baltic is through the Danish Straits. Ocean creatures could end up in the Baltic by mistake while seeking for a better habitat. «Getting out of the Baltic is more complicated for them,» Martin said.

Seal researcher Mart Jüssi said that the traveling routes of animals are probably influenced by the rapidly changing Arctic climate – ice might disappear from the places it used to exist for millions of years.

«If the surface temperature of seawater or streams plays some role in finding the direction, a small change could influence the route so that seeking for ice hundreds of kilometers away could lead the animals to some place they never intended to reach,» Jüssi explained.

Jüssi said that the Baltic Sea is a sort of «place behind the corner» since the entrance of the sea is located towards the west rather than north. When traveling along the coast, they reach Denmark with its straits and the brackish water typical of the Baltic. «This is a sign for many animals that they are traveling in an abnormal direction. But if some of them dare enter the unknown waters they will be trapped: the northbound route will not lead them back to the Arctic Ocean but the dead ends of the Baltic Sea.»

Jüssi estimates that this trap could prove fatal to many animals because their instincts would not allow them to undertake the thousand-kilometer return voyage to the Danish straits. They will wander along the Baltic coast until their strength gives up or they end up in fishing nets.

«Many exotic dolphins or whales have been eventually caught in fishing nets or lost their lives through collisions in shipping lanes with frequent traffic,» Jüssi said and added that some animals may have returned to the ocean but one cannot be certain of that.

Regarding the walrus, Jüssi said that its route leads northward. «There are wide sandy beaches in Latvia and an animal that size lying there can be sighted several kilometers away. It can stay away from the stony beaches in Estonia or seek shelter in some shallows,» Jüssi told the daily.

Can we speculate that more different species will be seen in the Baltic Sea in the future? «It is mostly an accident, I believe. There can be no regularity in that. Nor is the Baltic Sea suitable for them to live in. If they come here and cannot get out quickly, they will not survive long. The environment is not suitable for them,» Georg Martin explained.

Marine biologist Jonne Kotta also said that walruses do not like the Baltic Sea because the water is too warm and there is no suitable food here – large crabs, scallops, octopus or squid.

«If you happen to see a walrus on the beach, you certainly should not go near it, but instead immediately report it to the Rescue Board or the Environmental Board. A disturbed walrus is very dangerous for humans, because of its mass if nothing else. The animal can weigh up to two tons,» Kotta warned.

Kotta also added that, unlike the walrus, humpback whales have been encountered in the Baltic Sea before, but these are rare cases. «However, a humpback whale has been caught in Estonia, and one specimen caught in Saaremaa even ended up in the collection of the St. Petersburg Academy of Sciences, where it can still be viewed.»