Contributors and references


Tero Härkönen, Anders Galatius, Karin Hårding, Olle Karlsson, Markus Ahola, Lena Avellan, Petra Kääriä, Morten Tange Olsen.




This version of the HELCOM core indicator report was published in July 2018:

Distribution of Baltic seals HELCOM core indicator 2018 (pdf)

Earlier versions of this indicator are available at:

HOLAS II component - core indicator report July 2017 (pdf)



Anon (1895) Svensk fiskeritidskrift 1895.

Bäcklin, B.-M., Moraeus, C., Roos, A., Eklöf, E., Lind, Y. (2011) Health and age and sex distributions of Baltic grey seals (Halichoerus grypus) collected from bycatch and hunt in the Gulf of Bothnia. ICES Journal of Marine Science, 68: 183–188.

Bäcklin, B.-M., Moraeus, C., Kauhala, K., Isomursu. M. (2013) Pregnancy rates of the marine mammals - Particular emphasis on Baltic grey and ringed seals. HELCOM web portal.

Bergman, A., Olsson, M. (1985) Pathology of Baltic grey seal and ringed seal females with special reference to adrenocortical hyperplasia: Is environmental pollution the cause of a widely distributed disease syndrome. Finnish Game Res 44: 47-62.

European Commission (1992) Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora (Habitats Directive). Off. J. Eur. Union 206: 7–50.

European Commission (2008) Directive 2008/56/EC of the European Parliament and the Council establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive). Off. J. Eur. Union L 164: 19-40.

European Commission (2010) Commission Decision of 1 September 2010 on criteria and methodological standards on good environmental status of marine waters (2010/477/EU). Off. J. Eur. Union L232: 12-24.

European Commission (2017) Commission Decision of (EU) 2017/848 of 17 May 2017 laying down criteria and methodological standards on good environmental status of marine waters and specifications and standardized methods for monitoring and assessment, and repealing Decision 2010/477/EU. May 2017.

Galatius, A., Ahola, M., Härkönen, T., Jüssi, I., Jüssi, M., Karlsson, O., Verevkin, M. (2014) Guidelines for seal abundance monitoring in the HELCOM area 2014. Available at:

Goodman, S.J. (1998) Patterns of extensive genetic differentiation and variation among European harbor seals (Phoca vitulina vitulina) revealed using microsatellite DNA polymorphisms. Molecular Biology and Evolution 15(2): 104-118.

Fietz, K., A. Galatius, J. Teilmann, R. Dietz, A. K. Frie, A. Klimova, P. Palsbøll, L. Jensen, J. A. Graves, J. I. Hoffman and M. T. Olsen (2016). "Shift of grey seal subspecies boundaries in response to climate, culling and conservation." Molecular Ecology 25(17): 4097-4112.

Harding, K.C., Härkönen, T.J. (1999) Development in the Baltic grey seal (Halichoerus grypus) and ringed seal (Phoca hispida) populations during the 20th century. Ambio 28: 619-627.

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

Härkönen, T., Stenman, O., Jüssi, M., Jüssi, I., Sagitov, R., Verevkin, M. (1998) Population size and distribution of the Baltic ringed seal (Phoca hispida botnica). In: Ringed Seals (Phoca hispida) in the North Atlantic. Edited by C. Lydersen and M.P. Heide-Jørgensen. NAMMCO Scientific Publications Vol. 1: 167-180.

Härkönen, T., Harding, K.C., Goodman, S., Johannesson, K. (2005) Colonization history of the Baltic harbor seals: Integrating archaeological, behavioural and genetic data. Marine Mammal Science 21: 695-716.

Härkönen, T., Brasseur, S., Teilmann, J., Vincent, C., Dietz, R., Reijnders, P., Abt, K. (2007) Status of grey seals along mainland Europe, from the Baltic to France. NAMMCO Scientific Publications 6: 57-68.

Härkönen, T., Harding, K., Rasmussen, T.D., Teilmann, J., Dietz, R. (2007) Age- and Sex-specific Mortality Patterns in an Emerging Wildlife Epidemic: the Phocine Distemper in European Harbour Seals. PLoS ONE 2(9): e887. doi: 10.1371/journal.pone.0000887 

Harkonen, T., Bäcklin, B.-M., Barrett, T., Bergman, A., Corteyn, M., Dietz, R., Harding, K., Malmsten, J., Roos, A., Teilmann, T. (2008) Mass mortality in harbour seals and harbour porpoises caused by an unknown pathogen. The Veterinary Record 162: 555-556.

Harkonen, 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 (Phoca hispida botnica). PLoS ONE 3(4): e2006.doi:10.1371/journal.pone.0002006

Harkonen, T., Isakson, E. (2011) Historical and current status of harbour seals in the Baltic proper. NAMMCO Scientific Publications 8: 71-76.

Heide-Jørgensen, M.-P., Härkönen, T. (1988) Rebuilding seal stocks in the Kattegat-Skagerrak. Marine Mammal Science 4(3): 231-246.

Helle, E. (1980) Lowered reproductive capacity in female ringed seals (Pusa hispida) in the Bothnian Bay, northern Baltic Sea, with special reference to uterine occlusions. Annales Zoologica Fennici 17: 147-158.

Hult, J. (1943) Sälen och säljakten i Östersjön under de senaste decennierna. Svenska Jägereförbundets tidskrift 81: 365-373.

Jüssi, M., Härkönen, T., Jüssi, I., Helle, E. (2008) Decreasing ice coverage will reduce the reproductive success of Baltic grey seal (Halichoerus grypus) females. Ambio 37: 80–85.

Meier, H.E.M., Döscher, R., Halkka, A. (2004) Simulated distributions of Baltic Sea ice in the 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., Kunnasranta, M. (2015) Identifying foraging habitats of Baltic ringed seals using movement data. Movement Ecology DOI 10.1186/540462:015-0058-1.

Olofsson, O. (1933) Om vikaresälens hispida annelata storlek och föda mm.  Fauna och Flora 1933: 17-28.

Olsen, M.T., Wesley Andersen, L., Dietz, R., Teilmann, J. Harkonen, T., Siegismund, H.R. (2014) Integrating genetic data and population viability analyses for the identification of harbour seal (Phoca vitulina) populations and management units. Molecular Ecology 23: 815-831.

Sundqvist, L., Harkonen, T. Svensson, C.J., Harding, K.C. (2012) Linking climate trends to population dynamics in the Baltic ringed seal - Impacts of historical and future winter temperatures. Ambio. DOI 10.1007/s13280-012-0334-x

Teilmann, J., Riget, F., Harkonen, T. (2010) Optimising survey design in Scandinavian harbour seals: Population trend as an ecological quality element. ICES Journal of Marine Science 67: 952–958.


Additional relevant publications

Bergman, A. (1999) Health condition of the Baltic grey seal (Halichoerus grypus) during two decades. Apmis 107(1‐6): 270-282.

Bigg, M.A. (1969) The harbour seal in British Columbia (No. 172). Fisheries Research Board of Canada.

Boulva, J., McLaren, I.A. (1979) Biology of the harbor seal, Phoca vitulina, in eastern Canada. Fisheries Research Board of Canada.

Caswell, H. (2001) Matrix population models: Construction, analysis, and interpretation. Second edition. Sinauer, Sunderland, Massachusetts, USA.

Dietz, R., Heide-Jørgensen, M.-P., Härkönen, T. (1989) Mass deaths of harbour seals  Phoca vitulina in Europe. Ambio 18(5): 258-264.

Harding, K.C. Härkönen, T., Caswell, H. (2002) The 2002 European seal plague: epidemiology and population consequences. Ecology Letters 5: 727-732.

Harding, K.C., Härkönen, T., Pineda, J. (2003) Estimating quasi-extinction risk of European harbour seals: a reply to Lonergan and Harwood. Ecology Letters 6: 894-897.

Harding, K.C., Härkönen, T., Helander, B., Karlsson, O. (2007) Status of Baltic grey seals: Population assessment and risk analysis. NAMMCO Scientific Publications 6: 33-56.

Härkönen, T. Heide-Jørgensen, M.-P. (1990) Density and distribution of the ringed seal in the Bothnian Bay. Holarctic Ecology 13(2): 122-129.

Härkönen, T., Harding, K.C. (2001) Spatial structure of harbour seal populations and the implications thereof. Can. J. Zool. 79: 2115-2127.

Härkönen, T., Dietz, R., Reijnders, P., Teilmann, J., Harding, K., Hall, A., Brasseur, S., Siebert, U., Goodman, S., Jepson, P., Dau Rasmussen, T., Thompson, P. (2006) A review of the 1988 and 2002 phocine distemper virus epidemics in European harbour seals. Diseases of Aquatic Organisms 68: 115-130.

Harkonen, T., Harding, K.C.  (2011) Predicting recurrent PDV epidemics in European harbour seals. NAMMCO Scientific Publications 8: 275-284

Harwood, J., Prime, J.H. (1978) Some factors affecting the size of British grey seal populations. Journal of Applied Ecology: 401-411.

Heide-Jørgensen, M.-P., Härkönen, T. (1992) Epizootiology of seal disease. Journal of Applied Ecology 29: 99-107.

Heide-Jørgensen, M.-P., Härkönen, T. Dietz, R., Thompson, P. (1992) Retrospective of the 1988 European seal epizootic. Diseases of Aquatic Organisms 13: 37-62.

Hiby, L., Lundberg, T. Karlsson, O. Watkins, J., Jüssi, M., Jüssi, I., Helander, B. (2007) Estimates of the size of the Baltic grey seal population based on photo-identification data. NAMMCO Scientific Publications [S.l.] (6): 163-175. Oct. 2013. ISSN 2309-2491. Available at: <>. doi:

Karlsson, O., Härkönen, T., Bäcklin, B.M. (2008) Populationer på tillväxt. Havet 2008: 91-92.

Kokko, H., Helle, E. J., Ranta, E., Sipilä, T. (1999) Backcasting population sizes of ringed and grey seals in the Baltic and Lake Saimaa during the 20th century.  Annales Zoologici Fennici 36: 65-73.

Mortensen, P., Bergman, A., Bignert, A., Hansen, H.J., Härkönen, T., Olsson, M. (1992) Prevalence of skull lesions in harbour seals Phoca vitulina in Swedish and Danish museum collections during the period 1835-1988. Ambio 21: 520-524.

Olsen, M.T., Andersen, S.M., Teilmann, J., Dietz, R., Harkonen, T. (2010) Status of the harbour seal in Southern Scandinavia. NAMMCO Scientific Publications 8: 77-94.

Palo, J.U., Mäkinen, H.S., Helle, E., Stenman, O., Väinölä, R. (2001) Microsatellite variation in ringed seals (Phoca hispida): genetic structure and history of the Baltic Sea population. Heredity 86: 609–617. doi: 10.1046/j.1365-2540.2001.00859.x.

Sipilä (2003) Conservation biology of Saimaa ringed seal (Phoca hispida saimensis) with reference to other European seal populations. PhD Thesis.

Stenman, O., Halkka, A., Helle, E., Keränen, S., Nummelin, J., Soikkeli, M., ... Tanskanen, A. (2005) Numbers and occurrence of grey seals in the Finnish sea area in the years 1970-2004. In Symposium on Biology and Management of Seals in the Baltic area. Kala-ja riistaraportteja nro (346): 58-61.

Svensson, C.J., Hansson, A. Harkonen, T., Harding, K. (2011) Detecting density dependence in growing seal populations. AMBIO (2011) 40: 52–59. doi 10.1007/s13280-010-0091-7

Vanhatalo, J., Vetemaa, M., Herrero, A., Aho, T., Tiilikainen, R. (2014) By-Catch of Grey Seals (Halichoerus grypus) in Baltic.



HELCOM core indicator report,
ISSN 2343-2543