This marine environment made of a part of the Sea Channel, 7 coastal rivers, 1 marine river and 7 estuaries, welcome numerous species, a fauna and a flora that must be preserved, living in different habitats of a great diversity.

The Park is split into several types of landscapes. First of all, it has 7 estuaries. From Ambleteuse to Le Tréport, the estuaries are as follows : Slack, Wimereux, Liane, Canche, Authie, Somme and Bresle. The Park coastline also hastwo types of cliffs which differ by their shape, their composition and their history : the Pays de Caux cliffs in the south, and the Boulonnais cliffs in the north.

As for the beaches, they are characterised by a specific morphology. The areas alternately covered and uncovered by the tides are called "estran" or "intertidal". These are mainly sandy beaches, but a few rocky beaches can be found over some thirty kilometres.

Coastal areas are essential for a great amount of fish species : this is where we can find their spawning ground, where females lay their eggs, and where they feed the juveniles. Offshore, we findsubmarine dunes into the depths of the sea, created by Atlantic currents. Numerous species inhabit the open sea, including sole, harbour porpoise and white-beaked dolphin. Breaking the sand dunes, theridens, these rocky shoals, rise up. There, a diverse range of fauna and flore settle : brush sponges, seaweeds, anemones etc. More than 250 plant species have been identified.

On the estran, a distinction is made between thebay mud and thesalt marsh. The bay mud is the area covered daily by seawater. This is where specific marine invertebrates live, as well as small fish, glasswort and shorebirds.

The salt marsh is the vegetated area of the estuary, made up of a number of plant divided up by level : low marsh, medium marsh and high marsh.

Several projects are managed by the Marine Nature Park to better know and preserve the species it shelters : marine mammal and macro-waste census, fish population and conservation status, estuary vegetation knowledge etc.

The foreshores tops and dunes of the Marine Nature Park are home to3 rare and threatened species : the Kentish plover, the Little ringed plover and the Common ringed plover. They breed and raise their chicks here from april to september. As their eggs are highly sensitive to trampling, temporary quiet zones are set up around their nests by the Park field staff.

Thewrack zone is a natural habitat composed of debris. Its preservation is a major challenge as well for the survival of these species and other shorebirds, these birds living and feeding on the mudflats, so that they can continue to find shelter and food there.

In the Marine Nature Park boundaries, we also findcolonies of harbor and grey seals. At high tide, the individuals are foraging. At low tide, these mammals rest on the sandbank. From June onwards, this is where they give birth and nurse their young. This resting period on the shore is therefore vital for the seals. Any behaviour causing them to flee can have great impacts, even leading to the death of the most fragile individuals, such as newborn.Best practice gestures are recommended : maintain a long distance from the animal, use binoculars and a camera with a powerful zoom lens to observe it, sail parallel to the coast in a kayak. Awareness-raising and monitoring operations are regularly carried out at sites that are home to seals, by the Park's field staff among others.

• The estuary : l'estuaire
• The cliff : la falaise
• The Harbour porpoise : le Marsouin commun
• The bay mud : la slikke
• The salt marsh : le schorre / la mollière / le pré salé
• The Common ringed plover : le Grand gravelot
• The Kentish plover : le Gravelot à collier interrompu
• The Little ringed plover : le Petit gravelot
• The wrack zone : la laisse de mer
• The shorebird : le limicole
• The Harbour seal : le Phoque veau-marin
• The grey seal : le Phoque gris
• The newborn seal : le blanchon