Press release of WWF Finland, Metsähallitus Parks & Wildlife Finland, University of Eastern Finland and University of Helsinki (February 8th 2023)
Saimaa ringed seals will be moved from Pihlajavesi to Kolovesi and the southern Lake Saimaa between May and June. The aim of the translocation is to safeguard the growth of the Saimaa ringed seal population by supporting areas with declined ringed seal numbers and maintaining the remaining genetic diversity.
An estimated 440 Saimaa ringed seals inhabit the waters of Saimaa these days. Genetics research shows that the ringed seal population has become segregated into smaller sub-populations with typical genetic versions that only occur in these areas. The aim of the planned translocations is to enrich the genetic genome of the sub-populations and, at the same time, slow down their segregation by increasing the gene flow in Lake Saimaa.
– A more extensive and diverse gene base helps Saimaa ringed seals to cope better with environmental changes caused by, for example, climate change or chemicals, says Petri Auvinen, Research Director at the University of Helsinki.
– Translocations allow a genetically poor sub-population to recover characteristics that are good in terms of survival in the long term, says Auvinen.
The long-term effects of the translocations will be seen in the future ringed seal generations after it has been possible to obtain research data on whether the translocations have enriched the gene flow.
Five ringed seals to be moved from Pihlajavesi
The translocation will take place in May and June during the seal moulting season. In order to increase the gene flow and grow the local population, about five ringed seals will be taken from Pihlajavesi and relocated to Kolovesi and to the part of Lake Saimaa located south of Puumala.
Previous studies have shown that the Saimaa ringed seal population especially in Kolovesi is segregating genetically. The newest study shows that the same threat is occurring in the part of Lake Saimaa located south of Puumala. In Kolovesi the concern is also that the seal females giving birth have decreased significantly.
– At the beginning of the 21st century, 4–6 pups were born annually in Kolovesi, but in ten years, females giving birth disappeared almost completely. Through translocations, we aim to strengthen and diversify the Kolovesi ringed seal population. Kolovesi is largely a protected area, so it is a good and peaceful nesting environment for seals, says Miina Auttila, Senior Specialist in Nature Conservation at Metsähallitus, Parks & Wildlife Finland.
Encouraging example of Venla the seal
Saimaa ringed seals were moved once before, in 1992, when a ringed seal named Venla was translocated from Haukivesi to southern Saimaa in order to strengthen the declined seal population. After 30 years, Venla has descendants in several generations. Venla’s longevity – as the seal is still alive and at least 35 years old – shows that the translocation to the new living environment was a success.
– It was good to have a ringed seal from Savo in South Karelia. According to the study, Venla’s translocation has reduced genealogical inbreeding, which is known to affect birth rates and the mortality of pups in nests in the long term. The seal population in southern Lake Saimaa has grown relatively more strongly, partly thanks to the translocation, says WWF Regional Manager Ismo Marttinen, who works as Fieldwork Manager in the upcoming Saimaa ringed seal translocations.
Moving ringed seals are closely monitored
The seals that will be translocated are adults. Efforts are made to identify them based on fur patterns before they are caught in order to obtain as much information as possible about their characteristics and life cycle in advance. Fur patterns allow individuals to be monitored throughout their lives. DNA, on the other hand, also enables monitoring the next generations.
– Using pup fur or placentas found on nesting sites, DNA will help us find out if a pup is a descendant of a translocated seal in the future, says Auvinen.
Satellite tracking devices are installed on the translocated seals to provide accurate information on the position of the seal several times a day. Above all, post-translocation monitoring enables assessing immediate success: whether the seal will remain in the new area or not. The monitoring device is attached to the seal’s back fur and comes loose in the following spring at the latest during the moulting season.
– Satellite monitoring is the most effective way to get a large volume of observations on how animals move and behave in their living environment. No other method makes it possible to obtain such accurate, almost real-time information on the location and activity of the animal, says Marja Niemi, Researcher at the University of Eastern Finland.
The translocations of Saimaa ringed seals are part of Our Saimaa Seal LIFE project, and parties cooperating in the project include the Universities of Eastern Finland and Helsinki, Parks & Wildlife Finland and WWF Finland.
The Saimaa ringed seal population has been slowly increasing in recent years, but the subspecies is still very endangered. In addition to the low genetic variability of the population, the main threats to the Saimaa ringed seal are fish traps, climate change and disturbances caused by humans. The uniqueness of the Saimaa ringed seals has been further emphasised in the light of recent studies as the species does not seem to be nearly as closely related to the Baltic ringed seal and the Ladoga seal as previously thought.
Further information:
- Petri Auvinen, Research Director, Institute of Biotechnology, University of Helsinki +358 (0)50 448 2852, petri.auvinen@helsinki.fi
- Miina Auttila, Senior Specialist in Nature Conservation, Parks & Wildlife Finland (Saimaa ringed seal population monitoring and conservation): +358 (0)40 637 6324, miina.auttila@metsa.fi
- Marja Niemi, Researcher, University of Eastern Finland (monitoring methods: catching, satellite monitoring and individual identification): +358 (0)50 341 3654, marja.niemi@uef.fi
- Ismo Marttinen, Regional coordinator for WWF Finland (translocation of the ringed seal Venla, regional data of southern Lake Saimaa): +358 (0)50 434 9591, ismo.marttinen@gmail.com
- Our Saimaa Seal LIFE Project
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