Resultat och påverkan

Seal samples have been collected since 2000. Most samples are from grey seals, in recent years we have received 100-150 grey seal samples/year, altogether about 1800 samples. The demographic structure of the grey seal population has changed during the 2000s: the mortality rate of females <10 years of age has increased, which may affect the population growth rate. The proportion of females (especially those in the best reproductive age) has decreased in the population. Because also the birth rate has decreased, the population now produces fewer pups than in the early 2000s. The demographic structure of the grey seal catch differs between the sea areas: in the Gulf of Bothnia hunting mainly takes place on the ice in late spring and the majority of the catch is females (except pups), while in the Archipelago Sea hunting more often takes place in autumn and the majority of the catch is males. Human induced mortality, i.e. hunting and by-catch mortality may be a significant mortality factor of grey seals. On the basis of the results of this project we can estimate the status of the grey seal population in the Finnish sea area (demographic structure, reproductive potential, mortality rate, nutritional status, parasite load) and further, the environmental status of the Baltic Sea (HELCOM CORESET indicators) as well as human impact (e.g. hunting and fisheries) on seal populations.