Caspian Seal Breeding Area IMMA
Size in Square Kilometres
56 504 km2
Qualifying Species and Criteria
Caspian seal – Pusa (Phoca) caspica
Criterion A, B(2), C(1)
Marine Mammal Diversity
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The winter ice field in the north-east Caspian is the only breeding site for the entire population of the Caspian seal (Pusa caspica) species. Current species population estimates are in the region of 168,000 with a maximum annual pup production of around 34,000. Pups are born and nursed on the ice surface until weaning, while mating takes place in the water. Stable pack ice in rubble fields is optimum habitat for pupping. The main birthing period is from the end of January, peaking in the first week of February and continuing through the end of February, while mating takes place either towards weaning of the pup or immediately after lactation. The location of the main breeding aggregations depends on the pattern of ice formation and the extent of the stable ice in any one year. Imminent threats to the ice-breeding habitat include a diminishing ice field, water depth loss, and the expansion of industrial shipping.
Description of Qualifying Criteria
Criterion A – Species or Population Vulnerability
The Caspian seal is endemic to the Caspian Sea and is listed as Endangered by IUCN (Goodman & Dmitrieva 2016), and in the Red lists of all 5 littoral states (Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan). Since it is landlocked within the Caspian Sea it has no possibility to migrate to alternate areas, and therefore is entirely dependent on the Caspian environment.
The IMMA encompasses the habitat (the winter ice field of the north-east Caspian) used by the entire breeding population of Caspian seals to give birth, raise pups to weaning and to mate. The winter ice-field is therefore crucial to the survival of the species. Unsustainable hunting of adults (mainly females) and pups on the ice field from the 19th century to the 1990s resulted in collapse of the species population (Badamnshin 1961), estimated at 1–1.6 million in the mid-19th century, to around 100,000 individuals by 2005 (Härkönen et al. 2012). This decline, 90% since the mid-19th century, demonstrates the extreme vulnerability of the species. The species’ long-term viability depends on the physical characteristics of the northern ice field and on the breeding seals being free from hunting, shipping, or other forms of anthropogenic disturbance.
Criterion B: Distribution and Abundance
Sub-criterion B2: Aggregations
The Caspian Seal breeding population on the ice was surveyed annually from 2005 to 2012 (Härkönen et al. 2008; Dmitrieva et al., 2015). The minimum estimate for the number of pups born on the ice has ranged from ~8,000–9,000 in years 2007–2008 and 2010 and between ~22,000 and 34,000 in years 2005–2006, 2009 and 2011–2012. These figures may be compared with estimates of pup production from the 1980s of 50,000–90,000 (Krylov, 1990), although the methodology for these earlier estimates is not clear (see Härkönen et al., 2012). The minimum estimate for the number of adults on the ice has ranged from ~14,000 in 2010, ~32,000 in 2008, ~40,000 in 2005–2006, 53,000 in 2011 to ~63,000–67,500 in 2005, 2009 and 2012 (Dmitrieva et al. 2015).
The boundaries of the IMMA were defined primarily on the maximum geographic extent of the distribution of breeding seals observed in transect based aerial surveys conducted between 2005 and 2012 (Dmitrieva et al. 2015). The ice coverage in these survey years ranged from above average to very poor and so the extent can be taken as representative of the current ice regime. The southern boundary was extended beyond the distributions observed by Dmitirieva et al. (2015) to allow for ice extent greater than occurred in the 2005-2012 period, but which is known to occur occasionally from remote sensing data. The north eastern boundary was extended to the coast to allow years with minimal sea ice cover, during which seals are forced to pup on remnants of land-fast ice. Such years are likely to be more frequent under projected climate heating.
Criterion C: Key Life Cycle Attributes
Sub-criterion C1: Reproductive Areas
The main area for reproduction is the north Caspian winter ice-field (Härkönen et al. 2008; Dmitrieva et al. 2015). A core area in the general location known as “the Saddle” (Figure 1) has been most often frequented by mother-pup pairs in years when stable ice has covered this sea area. In other years, females have given birth close to the ice edge or on ice floes (Wilson et al. 2017b).
Mating also takes place in the winter ice field from late lactation to the post-pupping period. Individual males have been observed approaching females accompanied on the ice by their well-grown young. Male-female pairs have also been observed on the edge of large polynias during the immediate post-pupping period (late February to early March). Mating appears to take place in the water, either beneath the ice or in polynias (Wilson et al. 2017b).
Badamshin, B.I. 1961. Resources of the Caspian seal and the means of its rational utilization. Zapasy Kaspiyskogo tyulenya i puti ikh ratsional’nogo ispol’zovaniya. Trudy Soveshchaniy Ikhtiologicheskoy Komissii, 12:170-179. Translation: M. Slessers, ed. K. Hollingshead; U. S. Naval Oceanographic Office, Washington, DC 20390; 1970. Transferred to electronic copy and edited by M. Uhen and M. Kwon, Smithsonian Institution, 2007.
Dmitrieva. L., Härkönen, T., Baimukanov, M., Bignert, A., Jüssi, I., Jüssi, M., Kasimbekov, Y., Verevkin, M., Vysotskiy, V., Wilson, S. and Goodman, S.J. 2015. Inter-year variation in pup production of Caspian seals Pusa caspica 2005–2012 determined from aerial surveys. Endangered Species Research, 28: 209–223.
Goodman, S. and Dmitrieva, L. 2016, Pusa caspica . The IUCN Red List of Threatened Species 2016: e.T41669A45230700. https://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T41669A45230700.en. Downloaded on 31 January 2020.
Härkönen, T., Jüssi, M., Baimukanov, M., Bignert, A., Dmitrieva, L., Kasimbekov, Y., Verevkin, M., Wilson, S. and Goodman, S. 2008. Pup production and breeding distribution of the Caspian seal (Phoca caspica) in relation to human impacts. Ambio, 37: 356-361.
Härkönen, T., Harding, K.C., Wilson, S., Baimukanov, M., Dmitrieva, L., Svensson, C.J. and Goodman, S.J. 2012. Collapse of a marine mammal species driven by human impacts. PLoS ONE 7(9): e43130. doi:10.1371/journal.pone.0043130.g002
Krylov, V.I. 1990. Ecology of the Caspian seal. Finnish Game Research, 47: 32–36.
Prange, M., Wilke, T. and Wesselingh, F.P. 2020. The other side of sea level change. Communications Earth and Environment, 1:69. https://doi.org/10.1038/s43247-020-00075-6 | www.nature.com/commsenv
Wilson, S.C., Dolgova, E., Trukhanova, I., Dmitrieva, L., Crawford, I., Baimukanov, M. and Goodman, S.J. 2017a. Breeding behaviour and pup development of the Caspian seal, Pusa caspica. Journal of Mammalogy, 98: 143–153.
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. 2017b. Assessment of impacts and potential mitigation for icebreaking vessels transiting pupping areas of an ice-breeding seal. Biological Conservation, 214: 213–222.
Wilson, S.C., Crawford, I., Trukhanova, T., Dmitrieva, L., Goodman, S.J. 2020. Estimating risk to ice-breeding pinnipeds from shipping in Arctic and sub-Arctic seas. Marine Policy, 111: 103694.