Saimaa Lake IMMA

Size in Square Kilometres

6,363 km2

Qualifying Species and Criteria

Saimaa ringed seal – Pusa hispida saimensis

Criterion A, B (1), D (1)


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Lake Saimaa in Finland hosts an isolated endemic population of the Saimaa ringed seal (Pusa hispida saimensis), a freshwater seal subspecies. The Saimaa subspecies has been genetically isolated from the Baltic ringed seal (Pusa hispida botnica) for around 9,500 years. With only about 400 seals left, the Saimaa ringed seal population, is endangered but slowly increasing. The subspecies is affected by climate change, bycatch in fishing gear, recreational use of the region and industrial development.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

The Saimaa ringed seal (Pusa hispida saimensis) is listed as endangered (D, ver 3.1) on the IUCN Red List (Sipilä, 2016a). It is endemic to Lake Saimaa, Finland, a freshwater lake with very limited exchange to the Baltic Sea and other lake areas. Therefore, the proposed IMMA is the crucial and only available habitat for this endangered subspecies of ringed seals. The population dropped from between 2,000 and 4,000 animals about 5,000 years ago, to a low of 200 animals in around 1980 (Sipilä and Hyvärinen, 1998) and it is currently increasing by 3 % per year (Ympäristöministeriö 2011) with a recent count of ~400 individuals. With 135-190 mature individuals, the genetic diversity of the population may further decrease, making its viability questionable in the long term (Valtonen et al., 2014). The population is subdivided (Sipilä et al., 2005), making inbreeding a realistic threat. Climate change is one of the major threats that affects the viability of the population, which depends on fast ice for breeding, which is questionable for the long term given climate warming. Scientists are currently performing explorative use of artificial snow lairs to help Saimaa ringed seals reproduce successfully under the diminishing ice conditions observed in recent years.

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

The Saimaa ringed seal is resident to a single lake system, lake Saimaa, Finland. The subspecies is pagophilic (ice-breeding), giving birth in late February and early March. Saimaa ringed seals prefer to dig their lairs along the shoreline of small islands and islets, the only places in Lake Saimaa where the snow piles up in drifts (Sipilä, 1990).

The Saimaa ringed seal population consists of about 400 animals endemic to the Lake Saimaa area. The population in the lake is furthermore subdivided into smaller aggregations showing slowly decreasing individual heterozygosity in microsatellite loci, threatening the long-term viability of the subspecies (Valtonen et al. 2014), especially when facing a largely unknown future due to climate change-induced losses of breeding opportunities. Sundell et al. (2023) suggest that a translocation within the lake may be necessary to keep genetic diversity at a sustainable level.

The subspecies is a feeding generalist, preying mainly on smaller schooling fish. Animals feed locally around the haul outs, but can travel longer distances. Since almost no telemetry studies have been carried out there is not much fine scale information about feeding areas.

Criterion D: Special Attributes

Sub-criterion D1: Distinctiveness

The Saimaa ringed seal population is small, and genetically and geographically isolated. The subspecies’ adaptation to a freshwater ecosystem makes it exceptional among the pinnipeds, which are primarily marine.

Supporting Information

“A New Protection Strategy for the Saimaa Ringed Seal, Due to Climate Change” (PDF). Metsähallitus – Natural Heritage Services, Eastern Finland. 2011. Retrieved 2016-05-01.

Agafonova E. V., Verevkin M. V., Medvedev N. V., Sipilya T., Sokolovskaya M. V. and Shakhnazarova V. Y. 2007b. Distribution of haul-out sites of Ladoga ringed seals (Phoca hispida ladogensis Nordq.) and their abundance on the islands of the Valaam Archipelago (Lake Ladoga) in summer. Dynamics of game animal populations in Northern Europe. Petrozavodsk: KarRC RAS: 5–9

Hyvarinen, H. and Sipila, T. 1992. Saimaannorppa Phoca (Pusa) hispida saimensis. In: U. Elo (ed.), Maailman uhanalaiset eliiimet, pp. 68-71. Weiling and Gӧӧs, Vantaa.

Kunnasranta, M., Niemi, M., Auttila, M., Valtonen, M., Kammonen, J., & Nyman, T. (2021). Sealed in a lake—Biology and conservation of the endangered Saimaa ringed seal: A review. Biological Conservation, 253, 108908.

Saimaa Seal Pusa hispida ssp. saimensis has most recently been assessed for The IUCN Red List of Threatened Species in 2015. Pusa hispida ssp. saimensis is listed as Endangered under criteria D.

Sipilä, T. 2006. The past and future size of the Saimaa ringed seal (Phoca hispida saimensis) population. (In English and in Russian). In: V. M. Belkovich, A. N. Smelova and A. N. Boutunov (eds), Marine Mammals of the Holarctic, Collection of Scientific Papers. Saint Petersburg, Russia.

Sipilä, T. 2016a. Pusa hispida ssp. saimensis. The IUCN Red List of Threatened Species 2016: e.T41675A66991678.

Sipilä T., Helle E., & Hyvärinen H. 1990. Distribution, population size and reproductivity of the Saimaa ringed seal (Phoca hispida saimensis Nordq.) in Finland, 1980–84. Finnish Game Research, 47, 3-10.

Sipilä, T. and Hyvärinen, H. 1998. Status and biology of Saimaa (Phoca hispida saimensis) and Ladoga (Phoca hispida ladogensis) ringed seals. NAMMCO Scientific Publications. 1, (Jun. 1998), 83–99. DOI:

Sipilä, T., Hyvärinen, H. 1998. Status and biology of Saimaa (Phoca hispida saimensis) and Ladoga (Phoca hispida ladogensis) ringed seals. In: Heide-Jørgensen MP, Lydersen, C (eds) Ringed seals in the North Atlantic The North Atlantic. Marine Mammal Commission Scientific Publication 1, 83 –99

Sundell, T., Kammonen,, J.I., Mustanoja, E., Biard, V., Kunnasantra, M., Niemi, M., Nykänen, M., Nyman, T., Palo, J.U. Valtonen, M., Paulin, L., Jernvall, J. and Auvinen, P. 2023) Genomic evidence uncovers inbreeding and supports translocations in rescuing the genetic diversity of a landlocked seal population. Conservation Genetics 24: 155-165.

Valtonen, M., Palo, J.U., Aspi, J., Ruokonen, M., Kunnasranta, M. and Nyman, T. 2014. Causes and consequences of fine-scale population structure in a critically endangered freshwater seal. BMC Ecology 2014 14: 22.

Ymparistoministerio. 2011. Saimaannorpan suojelun strategia ja toimenpidesuunnitelma. – Ymparistoministerio 30.11.2011, Helsinki, 114.s. Available at:


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