A long time ago set colonies of seals in the Baie d'Authie. A proof of it, is a sketch of Francis Tattegrain, dates back 1890.
Nowadays you can see up to 100 seals. Two species can be observed in Berck-sur-Mer grey seal and common seal.
How to destinguish the phocids ?
Common seal: its head is rounded, it has a pronounced concavity between the forehead and nose and its nostrils from a V-shape its fur is dotted with very fine lighter-coloured markings. It measures between 1,5 and 1,8 metres in length. The male weights approximately 110kg and the female about 80kg.
Grey seals: its muzzle is an extension of its forehead; its nostrils are parallel and it has a light mottled coat. It is twice the size of the common seal measuring between 1,95 meters.
Meet them in the bay 2:30 before low tide (until 2:30 after low tide)