Patagonian Region

Patagonian Region 

a zoogeographical region of the ocean; sometimes considered a subregion of the Notalian region. The Patagonian region comprises the shelf and continental slope of the southern tip of South America and the adjacent islands. It is influenced by powerful cold currents, including the Peru (Humboldt) Current, the Cape Horn Current, and the Falkland Current. The surface temperature of the water in summer in the southern hemisphere is 8°-17°C, and in winter, 4°-13°C. The region’s biological productivity is high, with plentiful plankton and benthos, but the variety of species is significantly less than in the tropics. More than one-half of the species are endemic. The region has many species in common with the Antarctic region and somewhat fewer in common with the Kerguelen region.

The fauna of the Patagonian region is centered in the waters of Tierra del Fuego, in the Strait of Magellan, and in the waters off the southern tip of Chile. The fauna of the Chilean section, where the coast is precipitous and rocky, significantly differs from the fauna of the Argentinian section, which is a broad platform shelf. There are few species distributed throughout the entire Patagonian region. The benthos of the Patagonian region is dominated by large brown algae, mollusks, and echinoderms; there are few crabs or corals. Characteristic marine birds include albatrosses and king penguins. Marine mammals include southern fur seals (Arctocephalus australis), South American sea lions (Otaria byronia), and balaenids. Of commercial importance are the fishes hake, blue whiting Micromesistius australis, congrio, and sprat Sprattus fuegensis and such invertebrates as the stone crab Lithodes antarcticus, shrimp, the crab Munida gregaria, Argentinian squid (Illex argentinus), gastropods, bivalves, and sea urchins.

K. N. NESIS