Bogskar is a small group of islets, located 60 km from the nearest coast in the middle of the Baltic Sea, between Finland and Sweden. It is the southernmost point of Finland. The offshore islets are home to a colony of grey seals (Halichoerus grypus), which is currently listed as a protected species under the EU Habitats Directive. Grey seals are found throughout the Baltic Sea, but the northern part of the Baltic Proper is the most important place for the species, as the largest number of grey seals is found there. During winter the seals are in areas with open waters. The breeding season is in February and March and they breed preferable on ice, as breeding on land has a higher mortality. The grey seals in the Baltic Sea have had a tough time during the last century: in the beginning of the 20th century, they were hunted to extinction south of 59° northern latitude, and environmental pollution through the last three decades has caused low fertility rates. The recovery of the grey seal in the Baltic Sea has been slow and no established colonies have been described below in the Southern Baltic Proper. However, in the more northern areas of the Baltic Sea the annual increase of grey seals is positive, with an increase with up to 8% per year.
In 2012 Oceana conducted underwater recordings (with ROV and divers) around the small desolate island of Bogskär, and a grey seal colony was found at the skerry. Other species present were flounder (Platichthys flesus), two-spotted goby (Gobiusculus flavescens), red algae (such as Aglaothamnion roseum), and brown algae, such as bladder wrack (Fucus vesiculosus).
The Åland Island government has designated an area for protection near Bogskär.
