TALLINN - Since most Estonian residents have never seen a marbled seal in the wild, they were surprised to find out that the population of these Estonia-based sea mammals has rapidly declined over the last several years though it could be slowly restored, according to Mart Jussi, a researcher from the Estonian Fund for Nature.
There used to be a time when marbled seals, Phoca hispida, were spotted next to the Rusalka monument in the Tallinn harbor, when their total population in the Baltic Sea exceeded 30,000 animals, said Jussi, who is am expert on the animal.
By 2003, however, the population of these particular seals in Estonia amounted to roughly 500, or three times less than in 2001.
The natural food of seals is fish, including the Baltic herring, and the amount of accumulated toxic compounds in the Baltic herring exceeds that of the ocean fish by 30 to 100 times, Jussi explained.
Pollution is not only a problem for the Estonian waters but of the whole Baltic Sea. Before people realized the deadly effect of synthetic chemicals, the water was already polluted by the rapidly developing industrial enterprises of the region, the expert added.
"For some period of time 500 is enough for normal reproduction, but we have to take into account their habitat," said Jussi.
Apart from the marine pollution, which will fade within centuries, weather conditions are utterly important for survival of the marbled seals. Warm winters are deadly as there are no natural ice and snow lairs required for newborn baby seals.
The third major factor facilitating the animal's decline is the so-called human-caused mortality rate. Although it is prohibited to hunt seals, they still could die at human hands.
"Those are fish nets and disturbance in the national parks. Local people do not care about the special status of the parks and often go there for picnics and fishing as if it was a regular place," said Jussi.
"There is no information how many seals die in the nets of Estonian fishermen because the fishermen are not willing to talk about it. They are afraid of being accused of poaching," Jussi explained.
He admitted it was difficult to start using different, seal-friendly fishnets, but he referred to the Danish experience as a positive example. In Denmark, he said, the government covers investments into seal-friendly fishnets that are made of special material.
The Saaremaa bridge project would also harm the seals, according to Jussi, because it would block the natural migration route of the species.
One of the easiest ways to make a society think about a particular endangered animal is to present it to common people. For example, there are guided bird observation tours to Estonian forests and bogs. However, Jussi said it was not easy - sometimes impossible - with seals that are notoriously cautious and usually leave long before intruders can spot them.
"There has been only one place, in southern Estonia, where seals were permanently observable from the mainland. However, in the last several years the animals have not been spotted there," said Jussi.