>> Background information

Development

According to different estimates some 100 000 Grey seals and as many as 200 000 Ringed seals lived in the Baltic Sea in the early 20^th century. Since then intensive hunting promoted by bounties decreased the number of seals considerably. This development was enhanced by environmental toxins and diseases, which have lowered their reproductive success since the 1960s. During the 1970s the populations of Grey and Ringed seals reached their lowest levels at approximately 2 000 individuals of each species in the whole Baltic Sea.

After the decrease in hunting pressure and the reduction of toxin contents in the Baltic ecosystem during past decades, seal numbers have began to increase again. The increase has generally been strong and constant in the Baltic Sea during the early 21st century. The trend has been similar in Finnish territorial waters where more than 9 000 Grey seals have been counted in recent years, most of them in the Southwest Archipelago. Due to their mobility, there are considerable annual fluctuations in the local abundance of seals.

Seals as indicator species

As fish eating predators seals are at the top of the food chain in the Baltic Sea. Therefore they are strongly affected by heavy metals and other toxins, which have a tendency for bioaccumulation. The concentrations of these toxins increase on every level of the food chain. Seals depend on healthy fish populations for food, which, in turn, depend on healthy populations benthic organisms, primary producers, etc. Therefore the state of seal populations indicates the state of the whole Baltic Sea ecosystem.

Seals are currently threatened mostly by habitat loss due to coastal development. Another problem is the high mortality rate among young seals which often become entangled in fishing gear. Grey seal is also a game species in Finland. During the decades of lowest population sizes no game licenses were admitted, but in recent years the bag of Grey seals has been a few hundred individuals per year. After the seal populations begun to increase, the pressure to permit larger scale hunting started to grow as well. This is mainly due to the losses of catch and damage to fishnets experienced by fishermen.