Kerguelen Region

a marine zoogeographic region located in the subantarctic zone. It comprises Kerguelen Island, Heard Island, the Crozet Islands, the Prince Edward Islands, Marion Island, and Macquarie Island, which lie on submarine ridges and are separated from one another and from the continents by great distances and great depths.

The average annual temperature of the surface water is 3°-4°C; at a depth of 200 m the water temperature is 2°-3°C; ice does not form. There is a well-developed algae belt on the littorals and sublittorals. Two species of fish from the genera Harpagifer and Notothenia are common on the littorals. Also characteristic are representatives of the shallow-water antarctic-subantarctic sea urchins of the genus Abatus. Although the islands of the Kerguelen region have similar climatic conditions, their shelf fauna is impoverished and specialized to a significant degree as a result of the isolation of each island. In the entire Kerguelen region there are 37 species (from 28 genera) of starfish, 149 species (from 55 genera) of gastropods and bivalves, 74 species of crustaceans from the orders Isopoda and Tanaidacea, and only 19 species (from ten genera) of fish. The fauna is distributed in a mosaic pattern and is characterized by a high degree of endemism. Three-quarters of the species of the starfish, gastropods, and bivalves are endemic (approximately one-third of the genera); of Isopoda and Tanaidacea, more than one-third of the species are endemic; and more than half the fish species are endemic. In addition, the fauna of the Kerguelen region is characterized by the lack of isopods of the family Idoteidae, which are widely distributed in the ocean, and some fish that are usually found in antarctic waters (the genus Trematomus and the majority of representatives of the families Bathydraconidae and Harpagiferidae).

On the whole, the fauna of the Kerguelen region is sharply different from that of the New Zealand region, but it has some features in common with that of the Patagonian region. The fauna of the Kerguelen region is most closely related to that of Antarctica; the fact that these two regions have many genera in common, given the high percentage of endemic species, testifies to the ancient character of these links (probably pre-Tertiary). The Kerguelen region is sometimes considered a subregion of the Antarctic region.