Pinnipeds are marine predators. They hunt mainly fish. Spread out all over the world, there are many different species of marine predators, of which around 19 species of seals. Two of those species are found in the North Sea: the harbour seal and the grey seal. Every once in awhile, 'lost' species from northern regions are found in the North Sea, such as the walrus, the ringed seal, the harp seal and the hooded seal.