Fewer grey seals sighted in the Baltic Sea than last year

About 20,400 grey seals were sighted in the Baltic Sea this year. This is about 2,000 fewer than in 2008. The figures are based on the counts carried out by Sweden, Finland, Russia and Estonia this spring. The Finnish Game and Fisheries Research Institute was responsible for the counts carried out in Finnish sea areas.

The number of grey seals sighted during the counts has increased from about 10,000 at the start of the decade to more than 20,000. However, the number of seals sighted this year was almost two thousand smaller than in 2008. This does not necessarily mean that the populations are in decline. The fact that there have been few changes in the number of grey seals sighted during the past three years may simply indicate that the populations are no longer growing as rapidly as before. The results of the counts are influenced by such factors as the movements of the seals, weather conditions and, on some occasions, coincidence. The counts scheduled for the next few years will give a clearer indication of the population trends.

The weather conditions during the spring 2009 counts were very good. The counts were mostly carried out using aerial photography; only in Russia were the seals still counted from boats. This year, the largest grey seal populations were sighted in Swedish waters, while Finland came second. This is exactly the opposite to the situation last year. The changes can be explained by the fact that seals move from one place to another. The northern edge of the Baltic Sea main basin (the central Swedish archipelago and the south-western archipelago of Finland) still attracts the largest grey seal populations during the spring months. During the rest of the year, the distribution of the populations may, however, be different.

The counts are carried out during a period of two weeks in late May/early June in the main distribution area of the species. At this time, the seals are moulting, which means that the number of animals lying in highly visible places (on rocks and last ice floes) is at its peak. The counting period is kept short so that the risk of multiple counts of the same individuals moving from one place to another can be minimised. The number of animals sighted during the counts is smaller than the actual stock. This is because some of the seals are in the water and thus out of reach, even under optimum conditions. However, most of the populations can be counted, and as the count is carried out in the same manner each year, it gives a reliable picture of the overall trend.

Sightings of grey seals in late May/early June, by sea area and country. 1) Sandbäck – Södra Sandbäck , 2) Märket (Source: Baltic Sea international grey seal counting team 2009)

 

Grey seals observed during counts on the entire Baltic Sea (blue) in the last 9 years, the Finnish portion is marked in green.

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