1) The general geomorphology of the area, including the archipelago and the northern coastal formation of the San Jorge Gulf, has unique characteristics in the Argentine coast, combining the features of the Marifil Formation with the profusion of islands and islets, coves, bays and inlets, and the presence of coastal ridges and pediments, exceptionally well preserved, which evidence the changes in sea level during the Quaternary. In particular:
a. The islands provide breeding habitats for numerous species of birds and marine mammals such as the southern giant petrel (Macronectes giganteus), the Olrog’s gull (Larus atlanticus), the white-headed steamer duck (Tachyeres leucocephalus), and for the two-hair sea lion (Arctocephalus australis).
b. The overall formation presents a subjugating scenic beauty, resulting in a potential resource for tourism development.
2) The sea and its oceanographic processes, including physical and biological fronts originated by the characteristic geomorphological features of the Marine Park’s coast, such as points, islands and reefs, which can influence sediment distribution, plankton aggregation and the distribution of organisms in benthic communities.
3) The coastal marine biodiversity of this sector, one of the most outstanding of the Argentine coast, which has a profuse list of animal and plant species.
4) The intertidal environments, including marshes with the presence of Salicornia Sarcocornia perennis, have their own exclusive species. Several beaches are important as resting and feeding sites for shorebirds, especially Bahía Bustamante and Caleta Malaspina, the coastal sector from Punta Tafor to Punta Ezquerra and from Chata and Larga Islands to Melo Bay, as well as the bays of Isla Tova and Viana. Stopover sites are scarce at the continental level and the survival of these species depends on these environments. In particular, Bustamante Bay stands out for sustaining populations of red sandpipers and sea bream, both species with high priority for conservation.
5) Macroalgae forests and meadows, especially the cachiyuyo forests and Gracilaria gracilis meadows. Subtidal macroalgae assemblages provide habitats for a great diversity of benthic invertebrates and several species of coastal fish, some of which are important prey for seabirds and marine mammals. Gracilaria gracilis meadows in Argentina are restricted to Chubut, the most important of which are found in PIMCPA waters.
6) Fish assemblages, particularly chondrichthyans and reef fish, the latter residents of rocky caves locally called “salmoneras”.
7) Seabird and shorebird assemblages. The area is used by 55 species of marine and coastal birds that nest, feed and/or rest in the area. Some of these species are vulnerable, near threatened or endangered, such as the black-browed albatross, royal albatross, black petrel, black-headed shearwater, southern flamingo, Antarctic pigeon, Cory’s plover and red shorebird.
8) White-headed steamer duck. Emblematic species of the park, endemic to Chubut and considered globally vulnerable. Fifty percent of the world’s breeding population is found within the PIMCPA.
9) The Magellanic penguin, the PIMCPA gathers 10% of the world’s breeding population.
10) Olrog’s gull. The northern sector of the gulf constitutes one of the only two breeding areas of this endangered species, which breeds only in Argentina.
11) The Southern Giant Petrel with breeding colonies on Arce and Gran Robredo islands. The islands and islets of the Marine Park are also home to 25% of the Imperial Cormorants and almost 40% of the Black-necked Cormorants in Argentina.
12) Sea lion rookeries: PIMCPA has 24 single-hair sea lion rookeries and one double-hair sea lion rookery on Arce Island.
13) Diversity of cetacean species, including the Commerson’s dolphin, Risso’s dolphin, dusky dolphin, Risso’s dolphin, killer whale and southern right whale.
14) The temperate grasslands and mallines and the associated fauna.
15) The range of steppe mammals, in particular the mara, a large endemic rodent with a peculiar social structure.