In addition to Alonissos itself, four smaller islands (Pelagos, Gioúra, Psathoura et Pipéri) to the north make up this national marine park, where visitors will see Audouin’s gulls, cormorants, dolphins and monk seals. The seals in particular have been under threat on account of pollution, over-fishing and other human activities, but the creation of this park and other initiatives have reversed the trend. There is a small resident colony of them for visitors to observe.