Grey seals live in cold-temperate coastal regions, sub-arctic environments and pack ice. The grey seal is found on both sides of the north-Atlantic, including Greenland and Iceland, western Russia, Norway, the British Isles, Ireland, France and the Baltic Sea (Jefferson et al, 2008).
The worldwide population of grey seals is estimated at about 380,000 (Jefferson et al, 2008).
The Atlantic population is healthy and growing. This is partly due to the human over-exploitation of an Atlantic shark species which is a predator to the seal. This has enabled the population to grow. However the Baltic seal population is still recovering from hunting in the early 1900s (Jefferson et al, 2008).
In the UK, seal populations are monitored by aerial photography and direct counts from boats or the shore (Sea Mammal Research Unit, 2010).