Geography Reference
In-Depth Information
The Southern Ocean contains more than 250 species of fish. These include some fish such
as the Antarctic Ice Fish that possess an ability to survive sub-zero temperatures by produ-
cing anti-freeze glycopeptides in their blood. Other fish such as the Patagonian Toothfish
have grabbed the headlines in recent years due to their intense commercial exploitation.
This fish is found in cold temperate waters of the Southern Ocean, especially on seamounts
and continental shelves around the sub-Antarctic islands such as Prince Edward and South
Georgia. Patagonian Toothfish are slow-growing, but an adult can weigh about 10 kilo-
grams, and mature varieties might exceed 100 kilograms. They can survive for up to 50
years and have been sold worldwide under a variety of labels such as the Chilean Sea Bass
and Mero. Toothfish feed on krill, squid, and smaller fish.
Finally, we must recognize the humble 5-6-centimetre-long krill, a shrimp-like marine
crustacean. Krill feed on phytoplankton and zooplankton, and their collective estimated
biomass is thought to be around 500,000,000 tons. Krill is food for whales, seals, penguins,
squid a great deal en Peninsula, and fish, as it migrates up and down the water column.
Commercially, krill harvesting is carried out in the Southern Ocean, and something like
150,000 to 200,000 tons is harvested annually, mainly around the Scotia Sea. Krill is used
in aquaculture, pharmaceuticals, and in sport fishing as bait. Japanese and Russian con-
sumers also eat krill, but the volume consumed has declined since the 1980s and 1990s.
At their peak, something in the order of 400,000 tons of krill was harvested in the summer
season. Conservation measures were put in place in the early 1990s in order to stabilize
the total catch after fears were expressed that this was another living resource being over-
exploited by fishing vessels registered to the former Soviet Union and Japan. The latter
remains the most important exponent of krill harvesting both in the Southern Ocean and
the waters around Japan.
The geological and biological characteristics of the Antarctic are important to grasp.
Antarctica's historical evolution is one fundamentally shaped by mobility not rootedness.
Rather than being remote and isolated, scientists have over the last hundred years demon-
strated that the Antarctic is intimately connected to a series of physical systems including
the atmosphere, geology, sea level, and the evolution of planet Earth and the solar system.
One example that relates well this sense of inter-connectivity is the discovery of meteorites
in the Antarctic. The first meteorites were discovered in 1912, and since then more have
been discovered in a variety of locations. Some 25,000 discovered specimens are help-
ing us to better understand the creation and evolution of the solar system. The Allan Hills
region is particularly fecund because it is an area in which old ice is to be found, held
back by the mountains and kept snow-free by constant winds. These areas, in other words,
gradually end up revealing their meteorite hoards. Many others simply drift out towards
the Southern Ocean as ice sheets calve into icebergs.
