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Seal Monitoring
Monitoring Grey Seals on Craigleith
The island of Craigleith sits one kilometre off North Berwick’s coastline. It is but one in a rugged chain of several islands in the Firth of Forth, each of them unique in shape, size and their diversity of animal inhabitants. It is also one of the least accessible to humans. This makes it popular with a rich variety of seabirds and marine life, particularly breeding Grey seals (Halichoerus grypus).
The UK is home to roughly 40% of the world's Grey seal population, and about 90% of these breed in Scotland. The Firth of Forth supports one of the largest breeding colonies on the east coast with up to 4,000 pups born each autumn, mainly on the Isle of May but also in increasing numbers on Inchkeith and Craigleith.
_Greg_MacVean_(19).jpg "7 adult Grey seals lounge on a partly submerged rocky outcrop; the Bass Rock can be seen in the background, the sea is slightly rippled and slate-grey like the sky")
From October to December, female seals (cows) give birth to fluffy white pups at these breeding colonies, called “rookeries”. They will spend much more time on land compared to at other times of the year, making it easier to gain a better estimate of the population. As each female gives birth to one pup, which will remain on land for the first three or four weeks of its life, we can gain an understanding of how many breeding females there are and how the population is growing by counting the number of pups and their state of moult (pups begin to shed their white fur after around 12 days).
Every November and December, during rare respites between storms, a small group of two or three people venture onto Craigleith island to carefully carry out these population counts. This monitoring is achieved in partnership with the Fife Seal Group, who have been overseeing Grey seal pup counts in the inner Firth of Forth for many years. They work closely with the Forth Islands Heritage Group, and data is shared with the Sea Mammal Research Unit.
Great care must be taken when landing on Craigleith during the Autumn, as seals are very sensitive to disturbance. Counts are achieved from a distance with binoculars to avoid scaring the seals into the water. It is important that we all take the same care on the mainland around pupping or resting seals, as the presence of people and dogs can cause immense stress to both adults and pups. This goes for boats and kayaks too. Even when on the water, it is important to maintain a distance of at least 100m where possible.
Following the implementation of legislation to protect seal populations, which were severely dwindling by the 1960’s, Grey seals are now thriving in Scotland. Seals are limited by prey availability, so a vigorous seal population is also suggestive of a healthy population of the fish they feed on. By monitoring the number of seals in an area, we can therefore get a glimpse of the health of the local marine ecosystem as a whole.
See our Wildlife FAQs pages for information on what to do if you have seen a seal pup that you are concerned about on the beach.