Baltic Ringed Seal Area IMMA

Size in Square Kilometres

76,322 km2

Qualifying Species and Criteria

Baltic ringed seal – Pusa hispida botnica

Criterion B (1)



The Baltic Ringed Seal Area IMMA includes all the main ice field breeding habitat, as well as moulting areas and continuously used haul outs for the Baltic ringed seal (Pusa hispida botnica) population. Ringed seal pups are born and raised on ice and stay in snow lairs until weaning. The ideal habitat for pupping is stable fast ice with hummocks and ridges, and the ringed seals’ primary breeding locations depend on ice formation patterns and the extent of stable ice in any given year. The winter ice fields found in the Gulfs of Bothnia, Finland and Riga, and the Archipelago Sea are the exclusive breeding habitats for the Baltic ringed seal population. The current population of 20,000 individuals today is down from formerly 200,000 over 100 years ago. The recovery rate is slow due to the adverse effects of climatic change. Ice fields are shrinking and icebreaking operations to allow shipping during the winter months pose immediate threats to the seal breeding habitat. Other anthropogenic activities such as fishing, shipping, and industrial development of the Baltic Sea watershed area and coast also have severe negative impacts on the ringed seal population.

Description of Qualifying Criteria

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and resident populations

The Baltic ringed seal (Pusa hispida botnica) is one of five ringed seal subspecies, which occurs only in the Baltic Sea (Wilson and Reeder, 2005; Härkönen et al. 2015). Palo et al. (2001) found low genetic diversity in the subspecies, which was relatively recently dispersed into the Baltic Sea during the Holocene era. A morphometric study found that the Baltic, Ladoga (P.h. ladogensis) and Saimaa (P.h. saimensis) ringed seal populations are distinct (Hyvarinen and Nieminen 1990, Amano et al. 2002), and there is no evidence of Baltic ringed seal mixing with its Arctic counterpart. As such, the subpopulation should be considered as a stand-alone management unit.

Ringed seals were once the most abundant seals in the Baltic Sea, with a population of approximately 200,000 individuals over a century ago. However, the current population has drastically declined to only 15,000-20,000 individuals after a major population collapse in the mid-20th century (Halkka and Tolvanen, 2017).

Baltic ringed seals are strictly pagophilic, using fast ice as a platform to give birth and nurse their young (Helle, 1980, Härkönen, 2015). The pups, which are white-coated, are born in snow lairs and remain there with their mothers for up to six weeks, as documented by Helle (1980) and Lydersen and Smith (1989). Following the collapse of the snow lairs in late spring, both adult seals and pups remain on the ice to molt. Traditionally, four distinct subpopulations of Baltic ringed seals are recognized: those that  breed in 1) the Gulf of Bothnia (up to 20,000 seals; HELCOM, 2018), 2) the Gulf of Finland (200-300; Trukhanova et al., 2012; 2015, according to unpublished data this is might be down to ~100 animals, pers. comm), 3) the Archipelago Sea (~200-300 seals, Halkka and Tolvanen, 2017), and 4) the Gulf of Riga (1,000; Halkka and Tolvanen, 2017). Earlier studies, such as Palo et al. (2001), found no significant genetic differences among these subpopulations, but satellite tagging data (Härkönen et al., 2008) suggested that the exchange of individuals between them is very limited. The lack of movement between subpopulations has serious consequences for the small and unstable Gulf of Finland subpopulation in particular, for which warm winters and the absence of suitable ice for reproduction have been linked to reported reproductive failures (Härkönen et al., 2008).

Ringed seals in the Gulf of Finland form haul out sites on rocky ridges, individual rocks, and reefs between April and June and from September to November (Tormosov and Esipenko, 1990; Dmitrieva, 2000; Verevkin and Sagitov, 2004). The haul out sites are mainly located in the southern and central parts of the Russian waters of the Gulf of Finland, with the waters adjacent to the Kurgalsky Peninsula and Malyy and Moschnyy islands being characterized by large aggregations of seals (Verevkin and Sagitov, 1997; 2004; Loseva and Sagitov, 2015). Although other haul out sites are known in the Gulf of Finland, such as the Berezovyy Archipelago, the Vyborg Bay, and the Luga Bay, the aggregations in the Kurgalsky – Malyy – Moschnyy area are the largest. During the 1970s and 1980s, these aggregations consisted of 100-200 seals hauling out on the Kurgalsky and Kiskolsky Reefs, the Moschnyy and Bolshoy Tyuters islands, and the Vigryund Reef (Tormosov and Esipenko, 1986). Today, despite experiencing a significant decline in their population, Baltic ringed seals can still be observed gathering at various locations within the Kurgalsky – Malyy – Moschnyy area. Several authors (Verevkin and Sagitov, 1997; 2004; Loseva and Verevkin, 2012) have documented dozens of seals hauling out near the Kurgalsky Peninsula during the open-water season. The largest haulouts currently occur in the spring on the Kurgalsky Reef in the vicinity of Remisaar Island and Kiskolsky Reef, with group sizes reaching up to 70 individuals around Remisaar Island and 40-50 individuals on Kiskolsky Reef (Loseva and Sagitov, 2015). Moreover, mixed aggregations of ringed seals and grey seals are seen in the area of the Hitamatola tidal flat and an unnamed tidal flat close to the Ostrovnoy passage. Surveys conducted during April-June and September-November have reported periodic sightings of small groups of resting ringed seals at Luto, Pikhlisar, Kurgalsky capes, Kiryamo locality, and the Reymosaar Island (Loseva and Sagitov, 2015).

The warming of the climate (IPCC, 2022) is causing an increase in mild winter frequency in the Baltic Sea region, which is leading to a decline in breeding habitat for ringed seals (Sundqvist et al., 2012). The sea ice is freezing later, breaking up earlier, and melting faster, resulting in a rapid decrease in the total amount of suitable habitat for ringed seals to whelp, nurse their young and molt. As the amount of breeding and molting ice diminishes, the density of seals on the remaining ice fields increases, resulting in overcrowding in breeding habitats for females (Sundquist et al., 2012). This problem is further aggravated by the expanding industrial activities in the area, such as icebreaking operations and shipping, which leads to habitat fragmentation, disturbance to breeding animals, as well as increased risks of collisions and pollution (Wilson et al., 2017; Wilson et al. 2020). Thus, the decrease in ice fields triggers a density-dependent process that negatively impacts the weaning weight and survival rate of pups (Sundquist et al., 2012).

Supporting Information

Amano, M., Hayano, A., Miyazaki, N. 2002. Geographic variation in the skull of the ringed seal, Pusa hispida. Journal of Mammalogy 83: 370–380

Berta, A. and Churchill, M. 2012. Pinniped taxonomy: review of currently recognized species and subspecies, and evidence used for their description. Mammal Review, 42: 207-234.

Dmitrieva L. N. 2000. Comparative analysis of some ecological features of the Baltic and Ladoga ringed seal subspecies. Master thesis. St. Petersburg. 80 p. (In Russian)

Dyrcz, C. 2017. Analysis of Ice Conditions in the Baltic Sea and in the Puck Bay. Zeszyty Naukowe Akademii Marynarki Wojennej. 210. 1-1. 10.5604/01.3001.0010.6581.

Halkka, A. and Tolvanen, P. (eds.) 2017.The Baltic Ringed Seal – An Arctic Seal in European Waters – WWF Finland report 36.

Härkönen, T. 2015. Pusa hispida ssp. botnica. The IUCN Red List of Threatened Species 2015: e.T41673A66991604. Accessed on 05 April 2023.

Härkönen, T. and Heide‐Jørgensen, M.-P. 1990. Density and distribution of the ringed seal in the Bay of Bothnia. Holarctic Ecol. 13:122-129.

Härkönen, T., Lunneryd, S.G. 1992. Estimating abundance of ringed seals in the Bothnian Bay. Ambio 21: 497-510.

Härkönen T., Jüssi M., Jüssi I., Verevkin M., Dmitrieva L., Helle E., Sagitov R., Harding K. C.  2008. Seasonal activity budget of adult Baltic ringed seals. PLoS One. Vol.3, issue 4, pp. 1–10.

Härkönen, T. J., O Stenman, Mart Jüssi, Ivar Jüssi, R V. Sagitov and Michail Verevkin. “Population size and distribution of the Baltic ringed seal (Phoca hispida botnica ).” Nammco Scientific Publications 1 (2014): 167-180.

HELCOM core indicator report. 2018. Population trends and abundance of seals. Access:

HELCOM HOLAS 3 Dataset. 2023. Accessed on April 5 2023

HELCOM. 2023. HELCOM Thematic assessment of biodiversity 2016-2021. Baltic Sea Environment Proceedings No. 191., accessed 25.05.2023.

Helle, E. 1980. Reproduction, size and structure of the Baltic ringed seal population of the Bothnian Bay. PhD Thesis. Acta Universitatis Ouluensis series A Scientiae rerum naturalium No. 106 Biologica No. 11, 47 pp.

Helle, E. 1980. Aerial Census of Ringed Seals Pusa hispida Basking on the Ice of the Bothnian Bay, Baltic. Holarctic Ecology, 3(3), 183–189.

Helle, E. and Stenman, O. (eds.) 1990. Baltic seal populations in 1986-1990. Maailman Luonnon Siiiition WWF Suomen Rahaston Raportteja 1. 76 pp. (In Finnish or Swedish with English summary).

Hyvarinen, H., Nieminen, M. 1990. Differentiation of the ringed seal in the Baltic Sea, Lake Ladoga and Lake Saimaa. Finnish Game Research 47: 21–27.

IPCC. 2022: Climate Change 2022: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press. Cambridge University Press, Cambridge, UK and New York, NY, USA, 3056 pp., doi:10.1017/9781009325844.

Laidre, K.L., I. Stirling, L.F. Lowry, Ø. Wiig, M.P. Heide-Jørgensen, and S.H. Ferguson. 2008. Quantifying the sensitivity of arctic marine mammals to climate-induced habitat change. Ecological Applications 18: 97–125.

Loseva A. V., Sagitov R. A. 2015. New Data On Distribution Of Spring And Autumn Haul-Out Sites Of The Baltic Ringed Seals (Pusa Hispida Botnica) In The Gulf Of Finland. Biological Communications, (1), 15-40.

Lydersen, C., and Kovacs, K.M. 1999. Behaviour and energetics of ice-breeding North Atlantic phocid seals during the lactation period. Mar. Ecol. Progr. Ser. 187: 265–281.

Lydersen, C. and Smith, T.G. 1989. Avian predation on ringed seal Phoca hispida pups. Polar Biology 9: 489-490.

Meier, H. E. M., Descher, R. and Halkka, A. 2004. Simulated distributions of Baltic Sea-ice in warming climate and consequences for the winter habitat of the Baltic ringed seal. AMBIO 33: 249-256.

Oksanen, S.M., Niemi, M., Ahola, M.P. et al. 2015. Identifying foraging habitats of Baltic ringed seals using movement data. Mov Ecol 3, 33.

Palo, J., Mäkinen, H., Helle, E. et al. Microsatellite variation in ringed seals (Phoca hispida): genetic structure and history of the Baltic Sea population. Heredity 86, 609–617 (2001).

Rezvov G. V. 1977. Diet of ringed seal and grey seal in the Baltic Sea. Rybnoe khoziaistvo [Fishery], 1977, no. 7, pp. 24–26. (In Russian)

Stenman O, Verevkin M, Dmitrieva L, Sagitov R. 2005. Numbers and occurrence of ringed seals in the Gulf of Finland in the years 1997-2004″. “Symposium on Biology and Management of Seals in the Baltic area, 15 –18 February 2005 Helsinki, Riistaja kalataloudentutkimuslaitos. P/ 55-57.

Sundqvist, L., Harkonen, T., Svensson, C.J. et al. 2012. Linking Climate Trends to Population Dynamics in the Baltic Ringed Seal: Impacts of Historical and Future Winter Temperatures. AMBIO 41, 865–872.

Tormosov D. D., Esipenko A. G. 1986. Th e abundance of ringed and grey seals in the Gulfs of Riga and Finland. Finnish Game Res., 1986, vol. 44, pp. 33–36

Trukhanova, I., Dmirtieva, L., Bodrov, S., Sagitov, R. 2013. Positive trends in two endangered ringed seal subspecies in the Eastern Baltic Sea and Lake Ladoga. 20th Biennial Conference on the Biology of marine mammals. Dunedin, New Zealand, December 9–13, 2013, pp. 211–212.

Trukhanova, I., Dmirtieva, L., Bodrov, S., Sagitov, R. 2015. The Baltic ringed seal (Pusa hispida botnica) population estimation in the Eastern part of the Gulf of Finland of the Baltic Sea in spring 2013. Marine Mammals of the Holarctic. 2015. Collection of Scientific Papers. Vol. 2. Moscow, 374 pages.

Verevkin, M. V., Sagitov, R. A. 1997. Modern status of the Baltic ringed seal population in the Gulf of Finland. Rare mammalian species of Russia and adjacent territories. Publication of international conference, April 11–19. Moscow. Moscow, 1997, p. 19. (In Russian)

Verevkin, M. V., Sagitov, R. 2004. The number and distribution of seals in the Gulf of Finland. Proceeding of Biological Research Institute. 2004, issue 48, pp. 35–39. (In Russian)

Verevkin, M. V., Vysotskii, V. G., Sagitov, R. A. 2012. Aerial survey of Baltic ringed seals (Pusa hispida botnica) in the Russian part of the Gulf of Finland. Vestn. S.-Peterb. un-ta, 2012, ser. 3: Biologiia, issue 1, pp. 38–46. (In Russian)

Wilson, S.C., Crawford, I., Trukhanova, I., Dmitrieva, L. and Goodman, S.J. 2020. Estimating risk to ice-breeding pinnipeds from shipping in Arctic and sub-Arctic seas. Marine Policy, 111.

Wilson, S.C., Trukhanova, I., Dmitrieva, L., Dolgova, E., Crawford, I., Baimukanov, M., Baimukanov, T., Ismagambetov, B., Pazylbekov, M., Jüssi, M. and Goodman, S.J., 2017. Assessment of impacts and potential mitigation for icebreaking vessels transiting pupping areas of an ice-breeding seal. Biological Conservation, 214, pp.213-222.

Wilson, D. E., Reeder, D. M., eds. 2005. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494


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